chem exam

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If Kc = 0.68 for this reaction 3H2(g) + N2(g) ⇔ 2NH3(g) what is the value for Kc for the following reaction at the same temperature? 6NH3(g) ⇔ 9H2(g) + 3N2(g)

3.2

How many grams of FeCl3 are produced when the reaction (unbalanced) occurs with 6.3 grams Fe2S3 being consumed? (assume excess HCl) Fe2S3(s) + HCl(g) → FeCl3(s) + H2S(g)

9.83 g

How many half-lives must pass to consume 90.7% of a radioisotope?

3.43

How many half-lives must pass to consume 90.9% of a radioisotope?

3.46

What is the hydronium concentration of a 0.4 M solution of NaCN?

3.5x 10^-12M

Considering only the half lives of uranium-238 and iodine-131, which would be more appropriate for internal usage (ingestion) for medical tests? Explain.

8.1 days

Exactly 47.0 mL of 0.2 M HNO2 are titrated with a 0.2 M NaOH solution. What is the pH at the equivalence point ?

8.2

how many moles of electrons flowed through the cell in 15 minutes using 5.50 A of current? A. 0.051 B. 4950 C. 82.5 D. 589.63 E. 0.163

A 4.00-L flask containing 2.0 mol of O2 and 1.0 mol of N2 is in a room that is 22.0 °C. What fraction of the total pressure in the flask is due to the N2? A. 0.25 B. 0.33 C. 0.50 D. 0.67 E. 0.75

B. .33

The hydronium ion concentration of a 0.30 M solution of a weak acid is 5.7 x 10-4 M. What is the value of Ka for this acid? A. 5.7 x 10-4 B. 1.1 x 10-6 C. 1.0 x 10-3 D. 4.3 x 10-10 E. 1.9 x 10-3

B. 1.1 x 10 ^-6

CTQ 3a Which acid will produce the highest [H3O+] in a solution of a given molarity of acid? CH3COOH (Ka = 1.75 x 10-5) H2CO3 (Ka = 4.5 x 10-7) HI(Ka =3.0x109) HNO3 (Ka = 28) HNO2 (Ka = 5.1 x 10-4)

HI(ka=3x10^9)

Which gas will have highest velocity at 300 K: Ne, He, H2, and O2?

molecular ion

radical cation that results from loss of an electron -mass of an electron= 9.1 x 10 ^-28 g = .0005 amu (very small)

What mass in grams of barium sulfate (Ksp = 1 x 10-10) will dissolve completely in 418.7 mL of aqueous solution?

.001 g

Nitrosyl bromide decomposes according to the chemical equation below. 2NOBr(g) ↔ 2NO(g) + Br2(g) When 0.260 atm of NOBr is sealed in a flask and allowed to reach equilibrium, 22% of the NOBr decomposes. What is the equilibrium constant, Kp, for the reaction?

.0023

What mass of iodine contains the same number of atoms as 25.0 grams of chlorine?

89.5 grams

What mass of MgF2 will dissolve in 125 mL of water if Ksp = 6.5 × 10-9?

9.19x 10^-3 g

Substance X melts at 80.5 °C and boils at 218 °C, and the solid form is more dense than it liquid. Which of the following phase diagrams represent the phase diagram of this substance?

Which is more soluble in water? A. Al(OH)3 (Ksp = 4.6 x 10-33) B. CdS (Ksp = 8.0 x 10-27)

Which is the strongest oxidizing agent? A. Ni2+ B. Cu2+ C. Cr3+ D. K+

Which Ka value should be used to calculate the Kb for NH3? A. Ka of NH2- B. Ka of NH3 C. Ka of NH4+ D. Ka of H2O

Which is stronger acid? A. CH3COOH B. CCl3COOH C. CF3COOH

Which mixture will not produce a precipitate? A. Pb(CH3CO2)2 and Na2CO3 B. CaCl2 and Na3PO4C. NH4Cl and CuSO4

Predict the pH of 1.00 M NaBr in aqueous solution? A. 14.00 B. 10.00 C. 5.11 D. 4.20 E. 7.00

Ka for HCN is 6.2 x 10-10, Calculate the pH of 0.15 M KCN solution. A. pH=0.82 B. pH = 2.81 C. pH = 4.69 D. pH = 7.00 E. pH = 11.19

E. 11.19

Q and K

Q<K proceed to right, forward rxn and vice versa

strong acids

Strong Acids: HCl, HBr, HI, HClO4, HClO3, H2SO4, HNO3

what do all isotopes of magnesium have in common

name number of protons

Calculate ΔG°for the reaction of iron(II) ions with one mole of permanganate ions. MnO4-(aq) + 8H+(aq) + 5e- → Mn2+(aq) + 4H2O(l); E° = 1.51 V Fe3+(aq) + e- → Fe2+(aq); E°= 0.77 V

-3.57x 10^5

What is the hydronium ion concentration of a 2.73 M benzoic acid solution?

.013 M

For a 1.000 M HNO3 solution, [H3O+] = [NO3-] = 0.967 M, Ka = 28What is [HNO3] at equilibrium?

.033 M

What is the number of carbon-13 atoms found in a sample containing 200 carbon atoms?

1.11/100 x 200 = 2.22

What is the hydroxide concentration of a 1.28 M benzoic acid solution?

1.1e-12 M

What is the hydroxide concentration of a 1.43 M benzoic acid solution?

1.1e-12 M

The pH of an aqueous 0.10 M basic solution is 9.09. What is the Kb of this base?

1.23x 10^-4

Calculate the molarity of a solution that is prepared by adding water to 18.22 g of KF to give a final volume of 250.0 mL.

1.254 M

Determine the boiling point of 1.45 kg of water (Kb = 0.51 C/m) when when 22.9 g of sodium chloride is added to it.

100.28

what is the pH of a 0.3 solution of a weak base Kb=1.8x10-5? p

11.37

What is the pH of a 2.0 M solution of a weak base with Kb= 0.000024?

11.84

A mixture containing 1.00e2 g of H2 and 1.00e2 g of O2 is ignited so that water is formed according to the reaction: 2H2 + O2 →2 H2O How many grams of water are formed? Need to answer with units on this question. For example if the answer is 111 grams you can write: 111 g 1.11e2 g

113 g

Calculate the volume of 525 g of O2 at 25.7 torr and 25 °C.

11871 L

Which compound will give a molecular ion having m/z = an odd number? Select one: a. CH3CH2OH b. CH2BrCl c. CH3CO2H d. CH3CH2NH2 e. (CH3)2NCH2C≡N

CH3CH2NH2

Which of the following aqueous solutions would have highest osmotic pressure? A. 0.10 M NaCl B. 0.01 M C6H6O6 C. 0.30 M Na2SO4 D. 1.0 M HBrE. 0.01 M MgCl2

D bc (1 x 2)=2 highest of all of them

Buffer is a mixture of a weak acid and its conjugate weak base (HF and NaF) a weak base and its conjugate weak acid (NH3 and NH4+Cl-) Buffer is a type of the common ion effect (the presence of the conjugate base inhibits the ionization of the weak acid) Buffer is resistant to large changes in the pH upon the addition of small amounts of hydronium (H3O+) or hydroxide (OH-) ions. o Any acid added to the mixture is reacted by the base of the buffer pair o Added bases are reacted by the conjugate acid

Exercise 1: Which of the following could be used as a buffering pair? A.NH4Cl/NH3 B.HCl/NaCl C.NaOH/H2O D.NaCN/HCN E.Two of these F.Three of these G.All of these A and D

A strong acid is one that is more than 95% dissociated in water.A weak acid is one that is only slightly dissociated in water, generally less than 20% dissociated and often less than 10% dissociated

HOCL is an acid

Indicate which are potential bases. Select one or more: a. F- b. Al3+ c. HPO42- d. H2O e. CH3NH3+ f. NH4+

HPO42-, F-, H2O

Which is the correct solubility constant expression for Cu3(PO4)2? Select one: a. Ksp = [Cu2+] [ PO43-] / [Cu3(PO4)2] b. Ksp = [Cu2+] [ PO43-] c. Ksp = [Cu2+]3 [ PO43-]2 d. Ksp = [Cu2+]3 [ PO43-]2 / [Cu3(PO4)2] e. Ksp = [Cu2+]2 [ PO43-]3 / [Cu3(PO4)2] f. Ksp = [Cu2+]2 [ PO43-]3

Ksp = [Cu2+]3 [ PO43-]2

Which is strongest reducing agent? A. Li B. Na C. Al D. Sn E. Cu F. I- G. Br-

How does the mass of the molecular ion compare to the mass of the neutral compound?

Molecular ion mass is about the same.

Select all the INSOLUBLE salts from the list below. Select one or more: a. NaCl b. NH4Br c. PbI2 d. Sr(OH)2 e. MgCO3

PbI2, Sr(OH)2, MgCO3

When is chemical equilibrium reached? Select one or more: a. the rates of the forward and reverse reactions become equal b. the reverse reaction stops c. the temperature becomes constant d. the forward reaction stops e. the concentrations of products and reactants become equal f. all reactions stop

The correct answer is: the rates of the forward and reverse reactions become equal

Select all conditions is/are met at the equivalence point of the titration of a monoprotic weak base with a strong acid? Select one or more: a. The pH of the solution is more than 7.00. b. The moles of acid added from the buret equals the initial moles of weak base. c. The concentration of acid added from the buret must equal the concentration of base titrated. d. The pH of the solution is less than 7.00. e. The pH of the solution is equal to 7.00. f. The volume of acid added from the buret must equal the volume of base titrated.

The moles of acid added from the buret equals the initial moles of weak base., The pH of the solution is less than 7.00.

Titanium (Ti) is a strong, lightweight metal that is used in the construction of rockets, jet engines, and bicycles. It can be prepared by reacting TiCl4 with Mg metal at very high temperatures. The products are Ti(s) and MgCl2. Provide a balanced chemical reaction for the reaction described above. How many grams of Ti metal can be produced from a reaction involving 3.54 × 104 g of TiCl4 and 6.53 × 103 g of Mg?

Ticl4 + 2Mg = Ti + 2MgCl2 6.4x10^3Ti

tha galvanic cell

When the switch is closed,•The mass of the Cu electrode increases.•The concentration of Cu2+(aq) decreases.•The mass of the Zn electrode decreases.•The concentration of Zn2+(aq) increases.•Electrons (e-) are observed to flow through the wire. •The voltage measured with the voltmeter is 1.10 V. •Nitrate ions flow through the salt bridge.

This reaction occurs in an automobile battery Pb(s) + 2HSO4- (aq) + PbO2(s) + 2H3O+ (aq) → 2 PbSO4 (s) + 4 H2O (l)

Which atom is reduced? → Pb, What is the reducing agent? → Pb(s), Which is the oxidizing agent? → PbO2(s), Which atom is oxidized? → Pb

A certain galvanic cell has for its spontaneous cell reaction: Zn + HgO ↔ ZnO + Hg Which is the half-reaction occurring at the anode? Select one: a. Zn →Zn2+ + 2 e- b. Zn2+ + 2 e- → Zn c. HgO + 2 e- → Hg + O2- d. ZnO + 2 e- → Zn

A compound X has a molecular ion peak in its mass spectrum at m/z 136. What information does this tell us about X? Select one: a. X has a molecular mass of 136. b. The molecular formula for X is C8H8O2. c. The empirical formula for X is C4H4O. d. Both A (X has a molecular mass of 136) and B (The molecular formula for X is C8H8O2) are true. e. Statements (X has a molecular mass of 136), (The molecular formula for X is C8H8O2), and (The empirical formula for Xis C4H4O) are all true.

Assuming ideal behavior, which of the following aqueous solutions should have the highest boiling point? Select one: a. 0.75 m K2SO4 b. 1.00 m LiBr c. 0.50 m Ca(NO3)2 d. 0.75 m NaCl e. 1.25 m C6H12O6

Calculate the cell potential, at 25 °C, based upon the overall redox reaction below if [Zn2+] = 1.50 ´ 10-4 M, [Fe3+] = 0.0200 M, and [Fe2+] = 0.0100 M. Zn2+(aq) + 2 Fe2+(aq) Zn(s) + 2 Fe3+(aq)The standard reduction potentials are as follows: Zn2+(aq) + 2 e- Zn(s)E° = -0.763 V Fe3+(aq) + e- Fe2+(aq)E° = +0.771 V Select one: a. -1.665 V b. -1.534 V c. -1.439 V d. -0.008 V e. +0.008 V

Given the following system at equilibrium: N2(g) + 2O2(g) ↔ 2NO2 (g) + heat What is the effect on the equilibrium if you increase the concentration of oxygen? Select one: a. The equilibrium will shift toward reactants. b. The equilibrium will shift towards products. c. The equilibrium will not shift.

How does the volume of a gas (at constant n and T) change as the pressure is increased? Select one: a. no change b. decreases c. increases

The Ksp value for the slightly soluble salt AX is 2.3 x 10-7 The Ksp value for the slightly soluble salt BX2 is 5.0 x 10-14 Which salt is more soluble? Select one: a. BX2 b. AX

Which gas has the lowest density at 25 °C and 1 atm? Select one: a. O2 b. Ar c. N2 d. F2 e. C3H8

Which is stronger acid? Select one: a. CH3COOH b. CCl3COOH c. CF3COOH

nitrogen rule

even number= no N or even number of N odd number= odd number of N

Cu2+(aq) + Hg(l) → Hg2+(aq) + Cu(s) ∆G° = 65.3 kJ Is this reaction spontaneous? A. YES B. NO

The Ksp of Ag2SO4 is 1.4 × 10-5. Will a precipitate form when 250 mL of 0.12 M AgNO3 is mixed with 500 mL of 0.0050 M Na2SO4?

Which of these is the empirical formula for the unknown compound containing 30.4% N and 69.6 % O?

no2 n: 30.4g/14=2/17 mol/2.17: 1 o: 69.6g/16=4.35 mol/2.17: 2

Write the name for the following compound:SF2

sulfur difluoride

Equal masses of gaseous N2 and Ar are placed in separate flasks of equal volume at the same temperature. Tell whether the following statements is true or false. Statement: The N2 molecules collide more frequency with the wall of the flask than do the Ar atoms. Select one: True False

true

For both voltaic and electrolytic cells, electrons flow from the anode to the cathode. Select one: True False

true

In a redox reaction, electrons are transferred from the reducing agent to the oxidizing agent. Select one: True False

true

The following reaction is spontaneous at standard conditions. O2(g) + 4H+ (aq) + 4Ag(s) → 2 H2O(aq) + 4Ag+ (aq) Select one: True False

true

The following reaction is spontaneous at standard conditions. PbO2 (s) + 4H+ (aq)+ Sn(s) → Pb2+ (aq) + 2H2O (l) + Sn2+ Select one: True False

true

in a redox reaction, electrons are transferred from the reducing agent to the oxidizing agent. Select one: True False

true

By what (single step) process does caesium(Cs)-137 change to Barium(Ba)-137? A. α particle emission B. β particle emission C. gamma ray emission D. electron capture E. neutron capture

The standard reduction potentials for Ag+(aq) and Au+(aq) are shown in the table below. Which ion, Ag+(aq) or Au+(aq), exhibits the stronger pull on electrons? A. Ag+ B. Au+

Identify which of the following result in buffer solutions when equal volumes of the two solutions are mixed. a) 0.1 M KNO3 and 0.1 M HNO3 b) 0.1 M NaNO2 and 0.1 M HNO2 c) 0.1 M HCl and 0.1 M NH3 d) 0.2 M HCl and 0.1 M NH3 e) 0.1 M HCl and 0.2 M NH3

B and E

Boyle's Law (1660): V & P Charles' Law (1887): V & T Avogadro's Hypothesis (1812): V & n

Boyle: v=kb (1/p) at constant n and t Charles: v=kcT at constant n and p avogadros: v=kAn at constant t and p

Select all acids that would have a negative ΔG. Select one or more: a. HClO3 b. HClO4 c. H2SO4 d. HI e. H2O f. HF g. HNO2 h. HCl i. HBr j. HSO4- k. HNO3

HCl, HBr, HI, HNO3, HClO3, HClO4, H2SO4

Which combination would be best to buffer an aqueous solution at a pH of 3.0? Select one: a. H3PO4 and H2PO4- b. HNO2 and NO2- c. CH3CO2H and CH3COO- d. H2PO4- and HPO42- e. NH4+ and NH3

HNO2 and NO2-

Assign oxidation numbers to each atom in the following compound. HClO4

Oxidation number for Hydrogen → +1, Oxidation number for Chlorine → +7, Oxidation number for Oxygen → -2

Assign oxidation numbers to each atom in the following compound. Na2SO3 Oxidation number for Sulfur Oxidation number for Sodium Oxidation number for Oxygen

Oxidation number for Sulfur → +4, Oxidation number for Sodium → +1, Oxidation number for Oxygen → -2

Use 1.0 L of the buffer from Exercise 1. What is the change in pH after the addition of 0.020 moles of HCl (assume no change in total volume)?

-.05

Determine the freezing point of 1.9 kg of water (Kf = 1.86 degC/m) when 21.6 g of sodium chloride is added to it.

-.723

Determine the freezing point of 1.7 kg of water (Kf = 1.86 degC/m) when 26.6 g of sodium chloride is added to it.

-1.0

2.055 liters of steam at 100°C at 1 atm was collected and stored in a cooler container. What was the amount of heat involved in this reaction? The ΔHvap of water = 44.0 kJ/mol.

-2.95

Identify which of the following results in buffer solutions when equal volumes of the two solutions are mixed. Select one or more: a. 0.1 M NaOH and 0.2 M CH3COOH b. 0.2 M HCl and 0.3 M NH3 c. 0.1 M KNO2 and 0.1 M HNO2 d. 0.1 M KClO4 and 0.1 M HClO4 e. 0.2 M NaOH and 0.2 M CH3COOH f. 0.2 M HCl and 0.1 M NH3 g. 0.3 M NaCN and 0.1M HCN h. 0.2 M NaOH and H2O

0.1 M KNO2 and 0.1 M HNO2, 0.1 M NaOH and 0.2 M CH3COOH, 0.3 M NaCN and 0.1M HCN, 0.2 M HCl and 0.3 M NH3

how much energy (in joules) is needed to change 55.0 g ice at -5°C to steam at 110°C?

167.6 kj

What mass of CuI will dissolve in 1.00 liter of water if Ksp = 1.1 × 10-12?

2.0 X 10 ^-4 g

What is the pH of 0.1 M HNO2? Ka of HNO2 = 4.5 x 10-4 A. 11.83 B. 13.00 C. 7.00 D. 1.00 E. 2.17

2.17

Determine pH of a solution of 0.50 M HF and 0.20 M NaF.

2.77

What is the average mass of the atom from the given mass spectrum? Select one: a. 206.5 b. 207.2 c. 206.25 d. 207.8 e. 208.9

207.2

What mass of solid NaCH3CO2 should be added to 2.3 L of 0.4 M CH3CO2H to make a buffer with a pH of 5.21?

207.9 g

43.6 mL of 0.175 M calcium chloride reacts with 0.225 M sodium phosphate to produce solid calcium phosphate and aqueous sodium chloride.What volume of sodium phosphate is necessary to completely react with the calcium chloride?

22.6 mL

For the galvanic cell, Zn(s) + Cu2+(aq) ↔ Zn2+(aq) + Cu(s), which species is reduced? Select one: a. Cu(s) b. Cu2+(aq) c. Zn(s) d. Zn2+(aq)

A compound used as a dry-cleaning fluid was analyzed and found to contain 18.00% C, 2.27% H, and 79.73% Cl. Determine the empirical formula of the fluid.

c2h3cl3

What is always different among isotopes of an element? Select one or more: a. protons b. electrons c. charge d. neutrons e. mass number

d, e

The density of a gas is typically given as: 𝐷𝑒𝑛𝑠𝑖𝑡𝑦 = 𝑑 = 𝑔𝑟𝑎𝑚𝑠 (𝑔)𝑙𝑖𝑡𝑒𝑟 (𝐿) Use this definition of density and the ideal gas law to derive an equation that has only the density on the left-hand side and the other variables (P, T, MW) on the right-hand side.

d=p(mw)/rt

A metal, M, forms an oxide having the formula MO2 containing 59.93% metal by mass. Determine the atomic weight of the metal (M). Select one: a. 53.96 g/mol b. 58.93 g/mol c. 55.85 g/mol d. 63.55 g/mol e. 47.87 g/mol

Based on the information provided below: Moog 39 Table 1: The results (after equilibrium has been established) of adding solid Mg(OH)2 to 10.0 L of water at 25 °C. When 0.09700 grams of Mg(OH)2 are added to 10.0 L of water, how many grams dissolve? Select one: a. 0.09700 g b. 0.00070 g c. 1.66 x 10-3 g d. 1.65 x 10-4 g e. 0.09630 g

Calculate ΔG° for the oxidation of 3 moles of copper by nitric acid.Cu2+(aq) + 2e- → Cu(s); E° = 0.34 VNO3-(aq) + 4H+(aq) + 3e- → NO(g) + 2H2O(l); E° = 0.957 V Select one: a. -120 kJ b. -180 kJ c. -240 kJ d. -300 kJ e. -360 kJ

Uranium-235 has a half-life of 7.04 x 108 years. How many years will it take for 99.9% of a U-235 sample to decay? Select one: a. 7.0 x 105 yr b. 1.0 x 106 yr c. 4.7 x 109 yr d. 4.9 x 109 yr e. 7.0 x 109 yr

What particle(s) are produced in the following reaction? Select one: a. b. c.4-0-+1 d.4-2-he e.41-0-n

mass spectrum of nickel

# isotopes=5 add amounts of all peaks up= 1500, then each amount/1500 x 100= percent abundance average mass= (mass x mass number) + (mass x mass number).... /1500

Determine the mass in grams of lead (II) iodide that will dissolve in 500.0 mL of a solution containing 1.47 grams of lead (II) nitrate. Ksp of lead (II) iodide is 1.4 x 10-8. Hint: Think about common ion effect.

0.14 g

Steps to interpret a mass spectrum

1. Determine possible molecular formulas (see detail in part IV)2. Determine unsaturation number = [2C+2+N-(H+X)]/23. Look for fragmentation pattern4. Postulate the molecular structure consistent with molecular weight and m/z of fragments.

How many moles of oxygen atoms are there in 6.02 x 1024 atoms of CO?

10.0 mol

Isotopic abundances are different in other parts of the universe. Suppose that on planet Krypton we find the following stable isotopes and abundances for boron: What is the value of the average atomic mass of boron on planet Krypton in amu? 10B 10.013. 65.75% 11B. 11.009. 25.55% 12B. 12.014. 8.70%

10.442

If 21.2 mL of 1.4 M C2H5NH2 are titrated with 0.9 M HCl, what is the pH at 14.2 mL?

10.8

Determine the boiling point of 1.61 kg of water (Kb = 0.51 C/m) when when 28.6 g of sodium chloride is added to it.

100.31

Determine the boiling point of 1.40 kg of water (Kb = 0.51 C/m) when when 29.1 g of sodium chloride is added to it.

100.36

Determine the boiling point of 1.04 kg of water (Kb = 0.51 C/m) when when 24.5 g of sodium chloride is added to it.

100.41

What is the pH of 0.1 M NaOH? A. 14 B. 13 C. 7 D. 1 E. 2

What is the number of boron-10 atoms found in a sample containing 10,000 boron atoms?

1978 19.78/100 x 10000= 1978

What is the equilibrium constant for the reaction below at 25 °C? Fe2+ (aq) + 2Ag (s) ↔ Fe (s) + 2Ag+ (aq) A. 1.28 x 10-42 B. 7.80 x 1041 C. 1.45 x 1012 D. 6.88 x 10-13

Which do you expect to be the strongest acid? A. NH4+ B. PH4+

B. ph4+-bigger atom/longer bond

peak at 79 (m) and 81 (m+2) on mass spectrum

Which do you expect to be the strongest acid? A. HF B. HCl C. HBr D. HI

D. HI longest bond/largest size

The bond strength decreases as the bond length increases The longer and the weaker the bond to H, the stronger the acid

For molecules with more than one hydrogen atom, the hydrogen atom with the largest partial positive charge tends to be the acidic hydrogen.

The reaction below is used to product iron from iron ore: FeO(s) + CO(g) → Fe(s) + CO2 (g)

Which atom is reduced? → Fe, Which is the oxidizing agent? → FeO, Which atom is oxidized? → C, What is the reducing agent? → CO

Provided a heating curve for 1.00 mole of substance X below, what is specific heat capacity of liquid X? Molecular weight of this substance is 1.00 g/mole. a. 0.3 kJ/g·°C b. 0.5 kJ/g·°C c. 1 kJ/g·°C d. 2 kJ/g·°C e. 3 kJ/g·°C f. 4.184 J/g·°C

36.6 L of He gas at STP is pumped into a 10.0-L tank containing 1.0 atm of O2 at 25 °C. What is the total pressure in a tank at 25 °C? Select one: a. 2.0 atm b. 5.0 atm c. 5.4 atm d. 8.0 atm e. 8.8 atm

The values of Ksp for the slightly soluble salts MX and QX2 are each equal to 4.0x10-18. Which salt is more soluble? Select one: a. MX b. QX2

The volume of a sealed container with an ideal gas is increased by a factor of 10. Assuming the temperature is held constant, what happens to the pressure? a. Increases by a factor of 10 b. Decreases by a factor of 10 c.No change d. Impossible to determine

What is the cell potential for the spontaneous reaction between Zn/Zn2+(1M) and Cu/Cu2+(1M)? Select one: a. 0.34 V b. 1.10 V c. -1.10 V d. -0.42 V e. -0.34 V f. -0.76 V g. 0.76 V h. 0.42 V

What is the qualitative effect that the addition of solute has on the freezing point of a solvent? Select one: a. increases freezing point b. decreases freezing point c. no effect

What molecule is most likely to give a fragment ion at m/z = 43? Select one: a. cyclohexene b. 2-bromopropane c. propanoic acid d. toluene e. carbon dioxide

Which compound has the lowest pKa? Select one: a. H2O b. H2S c. NH3 d. CH4

Which concept can be used to explain the difference in acidity between ethanol (CH3CH2OH) and 2-fluoroethanol (FCH2CH2OH)? Select one: a. Size b. Inductive effect c. Resonance d. Hybridization

What nucleus is produced if thorium(Th)-225 decays by electron capture?

b. 225-89-Ac

AgCl does not dissolve well in aqueous solution with most of the compound precipitating to the bottom of the container and small amounts dissolving in the solution. If the chloride ions that are present in solution could be removed selectively, what would happen to the concentration of the silver ion in the solution? Select one: a. nothing b. impossible to determine without knowing the initial concentrations c. increase d. decrease

Assuming the reaction proceeds in the forward direction, what is reducing reagent?2 Fe3+(aq) + Co(s)→ 2 Fe2+(aq) + Co2+(aq) Select one: a. Fe3+(aq) b. Fe2+(aq) c. Co(s) d. Co2+(aq)

For electrolytic cells, which is true for E°? Select one: a. E° > 0 b. E° = 0 c. E° < 0

Given the following system at equilibrium: N2(g) + 2O2(g) ↔ 2NO2 (g) + heat What is the effect on the equilibrium if you increase the reaction vessel volume? Select one: a. The equilibrium will not shift. b. The equilibrium will shift towards products. c. The equilibrium will shift towards reactants.

Lead(Pb)-200 has a half-life of 21.5 hours. Starting with 3.77 mg of this isotope, how much would remain after 72 hours? Select one: a. 0.0 mg b. 0.098 mg c. 0.37 mg d. 0.47 mg e. 1.1 mg

Radioactive iodine-131 is used to treat thyroid cancer. A patient is given 20.0 mg of iodine-131 in the form of NaI, and after 8 days only 10 mg remains. How long, from the time of initial dose, do you think it will take until only 2.5 mg remain? Select one: a. cannot be determined from the information given b. 12 days c. 24 days d. 20 days e. 16 days

Sulfur exists in many forms with the general molecular formula Sn. If 1.00 g of sulfur is added to 500.0 g of carbon tetrachloride, and the freezing point of CCl4 is depressed by 0.156 degrees C, what is the molar formula of the sulfur molecule? Kf of CCl4 is 30 degrees C/m a. S8 b. S7 c. S12 d. S16

The Ksp of Ca(OH)2 is 5.5 x 10-6 at 25 °C. What is the concentration of OH-(aq) in a saturated solution of Ca(OH)2(aq)? Select one: a. 1.4 x 10-2 M b. 2.3 x 10-3 M c. 2.2 x 10-2 M d. 1.1 x 10-2 M e. 4.7 x 10-3 M

What mass of Na2SO4 must be dissolved in 238.5 grams of water to lower the freezing point by 2.40 ºC? The freezing point depression constant, Kfp, of water is 1.86 ºC/m. Assume the van't Hoff factor for Na2SO4 is 2.85. Select one: a. 15340.32 b. 0.00 c. 15.34 d. 0.27

What mass of Na2SO4 must be dissolved in 466.3 grams of water to lower the freezing point by 4.02 ºC? The freezing point depression constant, Kfp, of water is 1.86 ºC/m. Assume the van't Hoff factor for Na2SO4 is 2.85. Select one: a. 50237.30 b. 0.23 c. 50.24 d. 0.00

What mass unit is used to report the mass of atoms in the mass spectrum? Select one: a. gram b. no unit c. amu

Which concept can be used to explain the difference in acidity between acetic acid (CH3COOH) and ethanol (CH3CH2OH)? Select one: a. Hybridization b. Electronegativity c. Resonance d. Size

f an element has several isotopes, what single value for the mass could be used to characterize atoms of that element? Select one: a. Mass number b. Atomic number c. Average mass

Which is not spontaneous under standard conditions? A. Cu(s) + Ag+(aq) → Cu2+(aq) + Ag(s) B. Pb(s) + Cu2+(aq) → Pb2+(aq) + Cu(s) C. Cr2O72-(aq) + MnO2(s) → MnO4-(aq) + Cr3+(aq)

c I think??

Which is the weakest acid? Select one: a. HCl b. HI c. HBr d. HF

You want to purchase a salt to melt snow and ice on your sidewalk. Which would best accomplish your task using the least amount? A. NaClB. CaCl2C. MgSO4D. Na3PO4E. Mg(OH)2F. All are equally effective

na3po4 bc highest I value

s the overall photosynthesis reaction a redox reaction? 6 CO2(g) + 6 H2O(l) ↔ C6H12O6(aq) + 6 O2(g) A. Yes B. No

yes

mass percent comp for o In this molecule c20h14o4

(4 x 16/ 316) x 100 =20.1% mw=318

calculating average mass

(mass x abundance) + (mass x abundance)......

Use 1.0 L of the buffer from Exercise 1. What is the change in pH after the addition of 0.020 moles of NaOH (assume no change in total volume)?

+.05

mass spectra

-y axis- abundance or relative intensity x axis- m/z (mass to charge ratio) tallest peak-base peak

Factors Affecting Acid Strength (Stability of conjugate base (A-))

1. Electronegativity (Elemental Effect: occurs with elements in the same period) conjugate base acid 2. Bond Strength (bond length: occurs with elements in a different period) 3. Resonance (stabilization of conjugate base (anion))4. Inductive effect (effect of electronegative atoms or electron withdrawing group nearby)

When 79.3 g of a particular compound is dissolved in 0.878 kg of water at 1 atm pressure, the solution freezes at -1.34 °C. If the compound does not undergo ionization in solution and is nonvolatile, determine the molecular mass of the compound.

1.25x10^2 g/mol

hen a certain amount of HBr is dissolved in water, [Br-] = 1.2 × 10-3 M. What is [H3O+]? 1.2×10-3M 2.4×10-3M 6.0×10-4M 55M Cannot be determined

1.2x10^-3M

1.00 g of benzene, 1.30 g of acetyl chloride, 0.3 g of aluminum chloride were all added to a round bottom flask and heated to form acetophenone. What is the theoretical yield in grams of acetophenone for this reaction? Need to answer with units on this question. For example if the answer is 111 grams you can write: 111 g 1.11e2 g

1.53 g

What is the cell potential for this redox reaction? Zn(s) + 2Ag+(aq) → Zn2+(aq) + 2Ag(s) A. 0.04 V B. 0.76 V C. 0.80 V D. 1.10 V E. 1.56 V

1.56

Calculate the mass of Ag2CO3(s) produced by mixing 125 mL of 0.315 M Na2CO3(aq) and 75.0 mL of 0.155 M AgNO3(aq) and calculate the number of moles of the excess reactant remaining in solution. (molar mass of Ag2CO3 = 275.8 g/mole)

1.6 g

The hydronium ion concentration of a sample of lemon juice at 25 °C is 6.3 x 10-3 M. What is the hydroxide ion concentration?

1.6 x 10 ^-12 M

Determine the mass in grams of lead (II) iodide that will dissolve in 500.0 mL of a solution containing 1.78 grams of lead (II) nitrate. Ksp of lead (II) iodide is 1.4 x 10-8.

1.61x10^-4g

A solution of lithium carbonate, Li2CO3, reaches equilibrium with its solid after 0.0742 moles of the solid have dissolved in 1.00 liter. A student suggests that the value of Ksp for lithium carbonate is (0.0742)2(0.0742). Explain why the student is not correct and then calculate the correct value of Ksp for lithium carbonate.

1.63x10^-3

Two gases are added to a 1.00 L container: 2.0 moles of A; 4.0 moles of B. These gases react as follows: A(g) + 3 B(g) ⇔ C(g) + 2 D(g) At equilibrium the container contains 0.6 moles of D. Calculate the concentration of A at equilibrium.

1.7 M

Calculate the molar solubility of AgI in .0045 M KI(aq) at 25 C (Ksp of AgI=8.3x10^-7)

1.84x10^-4 M

Ammonia gas is synthesized according to the balanced equation below. N2(g) + 3 H2(g) → 2 NH3(g) If 2.77 L N2 react with 2.83 L H2, what is the theoretical yield (in liters) of NH3 at STP?

1.89 L

How many grams of solid Ca(OH)2(s) would be required to neutralize (react completely) with 103.4 mL of 0.503 M HCl(aq) (molar mass of Ca(OH)2(s) = 74.08 g/mole) 2HCl(aq) + Ca(OH)2(s) → CaCl2(aq) + 2H2O(l) Note: HCl(aq) → H+(aq) + Cl-(aq) Ca(OH)2(s) → Ca2+(aq) + 2OH-(aq)

1.93 g

What is the pH after 20.2 mL of 1.2 M NaOH have been added to 9.1 mL of 1.4 M HF?

13.6

What is the pH of a 0.20 M Ca(OH)2 solution?

13.60

What is the pH of a 0.20 M Ca(OH)2 solution? Select one: a. 7.00 b. 13.60 c. 0.60 d. 13.40 e. 0.40

13.60

Suppose that 0.50 grams of barium-131 are administered orally to a patient. Approximately how many milligrams of the barium would still be radioactive two months later

13.9

Ammonia gas is synthesized according to the balanced equation below. N2(g) + 3 H2(g) → 2 NH3(g) If 1.62 L N2 react with 3.19 L H2, what is the theoretical yield (in liters) of NH3 at STP? Include units in your answer.

2.13 L

he density of air at 1.000 atm and 25 °C is 1.186 g/L. a. Calculate the average molecular mass of air. From this value, and assuming that air contains only molecular nitrogen and molecular oxygen gases, calculate the mass % of N2 and O2 in air.

29 g/mol n2= 75% o2=25%

how many isotopes magnesium naturally occur on earth

Calculate the average molar mass of polyethylene when 4.50 g of the polymer is dissolved in benzene to produce 300.0 mL of solution, and the osmotic pressure is found to be 7.60 torr at 25 °C.

3.67 x 10^4

What is the hydroxide concentration of a 0.426 M acetic acid solution?

3.7e-12 M

Provided a heating curve for 1.00 mole of substance X below, what is molar heat of vaporization (ΔHvap) of the substance x? a. 10 kJ/mol b. 20 kJ/mol c. 30 kJ/mol d. 40 kJ/mol e. 50 kJ/mol f. 80 kJ/mol

30 kj/mol

Using these physical constants, calculate the final temperature if 8.11 kJ are added to 15.9 g ice at 0°C

41.9 celsius

Given the balanced chemical reaction:2NO (g) + O2(g) → 2NO2(g)Calculate the mass of nitrogen dioxide that can be made from 30.0 grams of NO and 30.0 grams of O2

46g NO2

What is the oxidation number of N in NaNO3?

Calculate pH of solution C, Kb for NH3 is 1.8 x 10-5

5.13

What is the pH of solution C, Kb for NH3 is 1.8 x 10-5 ?

5.13

What is the pH of the solution in the flask at the equivalent point of the titration of 25.0 mL 0.1 M HCl with 0.1 M NH3? Kb for NH3 is 1.8 x 10-5

5.28

What is the pH of a 0.0000013 M solution of hydrochloric acid?

5.9

At 90 degrees C, the following equilibrium is established:H2(g) + S(s) ↔ H2S(g) Kc = 6.8 X 10-2If 0.49 mol of hydrogen and 0.1 mol of sulfur are heated to 90 degrees C in a 1 L vessel, what will be the partial pressure of H2S at equilibrium?Give your answer with units as atm

9 atm double check this one

The atomic mass of rhenium is 186.2. Given that 37.1% of natural rhenium is rhenium-185, what is the other stable isotope? Select one: a. rhenium-187 b. rhenium-186 c. rhenium-188 d. rhenium-184

if the ratio of base to acid in a buffer increases by a factor of 10, the pH of the buffer Select one: a. increases by 1. b. decreases by 1. c. remains unchanged. d. increases by 10. e. decreases by 10.

What is the property of CH3CH2NH3+Cl- in an aqueous solution? A. AcidicB. BasicC. Both acidic and basic D. Neutral

A. acidic

The Ksp value for the slightly soluble salt AX is 2.3 x 10-7 The Ksp value for the slightly soluble salt BX2 is 5.0 x 10-14 Which salt is more soluble?

solubility rules

All group 1A are soluble. All NH4+ are soluble. NO3-, CH3COO- are soluble. Cl-, Br-, I- are soluble EXCEPT with Ag+, Pb2+ and Hg22+ SO4- are soluble EXCEPT Ba2+, Pb2+, Ca2+ and Sr2+ OH- are insoluble EXCEPT group 1A. S2- are insoluble EXCEPT group 1A & 2A and NH4+ CO32-, PO43- are insoluble EXCEPT group 1A and NH4+

R = gas constant = 0.08206 L•atm/mol•KV = volume of the gas (L) T = temperature (K) PV = nRT Volume Gas constant n = amount (moles)P = pressure (atmospheres or atm) (1 atm = 760 torr)

Always use Temperature in Kelvin for Gas Law calculationsT (K) = Kelvin or absolute temperature = T(°C) + 273.15 T (K) is always > 0

Calculate the Kb for A- (Ka of HA is 1.0 x 10-5) ? Kb = 1.0 x 10-5 Kb = 1.0 x 10-14 Kb = 1.0 x 10-9 Kb = 1.0 x 1019 Kb = 1.0 x 109

Select pair(s) of compounds that would give a precipitate when aqueous solutions of them are mixed. Select one or more: a. Na2CO3 and H2SO4 b. CoCl2 and Na2SO4 c. AgNO3 and KCl d. CuBr2 and K2CO3 e. HNO3 and NH4I f. KCl and KNO3 g. CdSO4 and K2S h. BaCl2 and KClO4 i. NaOH and MgCl2

CuBr2 and K2CO3, CdSO4 and K2S, NaOH and MgCl2, AgNO3 and KCl

In which equilibrium system(s) will an increase in the pressure cause the reaction to shift to the right? Select one or more: a. H2(g) + F2(g) 2 HF(g) b. N2(g) + 3 H2(g) 2 NH3(g) c. CaCO3(s) CaO(s) + CO2(g) d. 2 NOBr(g) 2 NO(g) + Br2(g) e. 2 H2O(g) + O2(g) 2 H2O2(g)

N2(g) + 3 H2(g) 2 NH3(g), 2 H2O(g) + O2(g) 2 H2O2(g)

Identify 0.1 M solutions of each compound is acidic, basic, or neutral. NaNO3

NaNO3 → Neutral, NaHCO3 → Basic, NH4Cl → Acidic, KNO2 → Basic, HCl → Acidic, H2S → Acidic, NaF → Basic, LiF → Basic, Na2S → Basic, KCN → Basic, Na3PO4 → Basic, LiClO4 → Neutral, CH3COONa → Basic, NaCl → Neutral, NH4NO3 → Acidic

Select all the INSOLUBLE salts from the list below. Select one or more: a. AgBr b. Na2S c. CaCO3 d. NaOH e. Na2CO3 f. NaCl g. PbCl2 h. CuS i. NH4Cl j. Mg(OH)2

PbCl2, Mg(OH)2, CaCO3, AgBr, CuS

pH Calculations 𝑝𝐻 = −𝑙𝑜𝑔[𝐻3𝑂+] 𝑝𝑂𝐻 = −𝑙𝑜𝑔[𝑂𝐻−] 𝑝𝐻 + 𝑝𝑂𝐻 = 14

Strong acid (100% dissociation): HCl, HBr, HI, HClO4, HClO3, H2SO4, HNO3 [HA] = [H3O+] and pH = -log[H3O+] Strong Base (100% dissociation): NaOH, LiOH, KOH, RbOH, CsOH, Ca(OH)2, Sr(OH)2, Ba(OH)2 [B] = [OH-] and pOH = -log[OH-] pH = 14 - pOH

Determine the % ionization of 1 M hydrocyanic acid (HCN), Ka = 4.0 x 10-10 Select one: a. 0.002 % b. 0.2 % c. 0.4 % d. 0.004 % e. 1 %

Estimate the value of the equilibrium constant from the graph. a. 2.333 b. 0.070 c. 0.048 d. 0.030 e. 0.43

For electrolytic cells, which is true for ΔG°? Select one: a. ΔG° > 0 b. ΔG° = 0 c. ΔG° < 0

For the reaction: PCl3(g)+Cl2(g) ⇌ PCl5(g), Kc=1.00×103 A 5.00-liter box at 25 °C has 0.1100 moles of PCl3(g), 0.0200 moles of Cl2(g), and 0.200 moles of PCl5(g). Is the system now at equilibrium? Select one: a. No b. Yes c. Cannot be determined

Given the following system at equilibrium: N2(g) + 2O2(g) ↔ 2NO2 (g) + heat What is the effect on the equilibrium if you add a catalyst? Select one: a. The equilibrium will not shift. b. The equilibrium will shift towards products. c. The equilibrium will shift towards reactants.

Given the following system at equilibrium: N2(g) + 2O2(g) ↔ 2NO2 (g) + heat What is the effect on the equilibrium if you increase the N2 concentration? Select one: a. The equilibrium will shift towards products. b. The equilibrium will not shift. c. The equilibrium will shift towards reactants.

If Q > K, which direction will a reaction proceed to reach equilibrium? Select one: a. reverse b. impossible to determine without knowing the equilibrium constant value c. forward d. no change in direction

What reaction occurs when a zinc bar in a 1M zinc nitrate solution correctly connected to a lead bar in a 1M lead (II) nitrate solution to form a voltaic cell. You will need to refer to a chart of standard reaction potentials Select one: a. more Zn+2 and more Pb are formed b. more Zn and more Pb+2 are formed c. more Zn+2 and more Pb+2 are formed d. more Zn and more Pb are formed

Which of these substances has an abundant and distinctive molecular fragment in its mass spectrum at m/z = 93 and 95? Select one: a. 1-bromobutane b. (2,2-dimethylpropyl)benzene c. (3-methylbutan-2-yl)benzene d. 4-methylhexan-3-one e. 3-methylhexan-2-one

which has more atoms? 1.008 g H 12.011 g C 24.305 g Mg 39.95 g Ar

all have same number ( 1.008 g H x 1 mol H/1.008g H)

Assuming ideal behavior, which of the following solutions should have the lowest freezing point? Select one: a. 1.0 m RbBr(aq) b. 1.0 m MgCl2(aq) c. 1.0 m NH3(aq) d. pure H2O e. 1.0 m C6H12O6(aq)

The pH of an aqueous 0.10 M basic solution is 9.09. What is the Kb of this base? Select one: a. 8.0 x 10-10 b. 1.5 x 10-9 c. 9.0 x 10-6 d. 1.6 x 10-5 e. 1.2 x 10-5

What is [OH-] in a 1.5 M solution of CH3NH2? Kb of CH3NH2 = 4.4 x 10-4 A. 4.4 x 10-4 B. 6.6 x 10-4 C. 2.6 x 10-2 D. 2.9 x 10-4 E. 1.7 x 10-2

c. 2.6

What is the molar mass of an ideal gas if a 0.622 g sample of this gas occupies a volume of 300. mL at 35 °C and 789 torr? a 44.8 g/mol B. 48.9 g/mol C. 50.5 g/mol D. 54.5 g/mol

c. 50.5 g/mol

In the following mass spectrum, which fragment could account for the loss between the molecular ion and m/z 135?

ch(ch3)2

238Bi decays with emission of an α particle. The resulting nuclide is unstable and emits a β- particle. What is the symbol of the element formed from decay.

check pics

peak at 35 (m) and 37 (m+2) on mass spectrum

An important endothermic gas phase reaction for the commercial production of hydrogen is CH4(g) + H2O(g) ↔ 3H2(g) + CO(g) What will happen to the number of moles of hydrogen at equilibrium when carbon monoxide is removed? Select one: a. no change b. need the equilibrium constant to determine if a change occurs c. decreases d. increases

Which process occurs at the cathode in a voltaic cell? Select one: a. neutralization b. oxidation c. proton transfer d. reduction

Which species is the conjugate acid of ammonia, NH3? Select one: a. H4N b. H3N+ c. H2N- d. H4N+

Correctly spell the chemical name of N2O4.

dinitrogen tetroxide

A voltaic cell consists of an Au/Au3+ electrode (E° = 1.50 V) and a Cu/Cu2+ electrode (E° = 0.34 V). Calculate [Au3+] if [Cu2+] = 1.20 M and Ecell = 1.13 V at 25°C. Select one: a. 0.001 M b. 0.002 M c. 0.01 M d. 0.02 M e. 0.04 M

For the reaction: Zn(s) + Cu2+(aq) ---> Zn2+(aq) + Cu(s), which species is oxidizing agent? Select one: a. Cu(s) b. Zn(s) c. none d. Zn2+(aq) e. Cu2+(aq)

Which quantity can be used to calculate equilibrium constants (Kc)? A. Initial concentrationsB. Initial molesC. Equilibrium concentrations D. Equilibrium molesE. Any given concentrations F. Twooftheabove

equilibrium concentrations

If ΔG < 0, what condition is true? Select one: a. K < 0 b. K = 0 c. K = 1 d. K > 0 e. K < 1 f. K > 1

A mixture containing 9 mol of F2 and 5 mol of S is allowed to react as follows: 3F2 + S → SF6 What is the limiting reactant?

You add X g NaCl to Y g H2O and the freezing point is depressed by Z °C. How much would the boiling point change for this same solution?

less than z Celsius

What is the formula of the compound corresponding to the combination of magnesium and nitrogen

mg3n2

What is the definition of molarity?

mol solute/L of solution

Which of these is the empirical formula for the unknown compound containing 36.8% N and 63.2 % O?

n2O3

dissociation rxn

na2so4 (s) =(h20)= 2 na+ (aq) + so42- (aq) nacl (s) =(h20)= na+ (aq) + cl- (aq)

n an electrolytic cell, reduction occurs at the ________ oxidation occurs at the ________

reduction occurs at the ________ → cathode, oxidation occurs at the ________ → anode

if you select 1000 carbon atoms at random, the total mass will most likely be

slightly more than 12000 amu

Calculate the density of NH3 at 850 torr and 100 °C.

.62 g/l

What is oxidation number of Cr atom in Cr2O72-?

Why does [HOCl]0 = [HOCl]eq? HOCl is a weak acid Coefficients are the same Equilibrium concentrations are always equal HOCl did not dissociate any Two of the above

A and D

How many grams of zinc were plated onto the cathode in 15 minutes using 5.50 A of current? A. 0.026 g B. 1.67 g C. 0.102 g D. 3.34 g

Percent dissociation is the percentage of the original acid molecules that have reacted to produce the conjugate base and H3O+. Which has higher percent dissociation? 0.5 M solution of HA has [H3O+] = 1 × 10-4 M 0.5 M solution of HX has [H3O+] = 1 × 10-3 M

The relative strength of an acid is determined by the relative concentration of H3O+ produced at equilibrium for a given molarity of the acid. Which is stronger acid? 0.5 M solution of HA has [H3O+] = 1 × 10-4 M 0.5 M solution of HX has [H3O+] = 1 × 10-3 M

What is the oxidizing agent in the reaction below? Ni(s) + H2O2(aq) + 2H+(aq) → 2H2O(l) + Ni2+(aq) A. Ni(s)B. H2O2(aq) C. H+(aq) D. H2O(l)E. Ni2+(aq) F. NiG. HH. O

What is the oxidizing agent in this reaction? Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g) A. Na(s)B. H2O(l)C. NaOH(aq) D. H2(g)

Which type of titration will produce an acidic solution at the equivalence point? A. strong acid / strong base B. strong acid / weak base C. weak acid / strong base

Why does [H3O+] = [OCl-]? HOCl is a weak acid Coefficients are the same Equilibrium concentrations are always equal HOCl did not dissociate any Two of the above

Zn2+(aq) + 2e- → Zn(s) Cu2+(aq) + 2e- → Cu(s) A. Zn2+(aq) B. Cu2+(aq) C. Cu(s)D. Zn(s) E°red = -0.76 V E°red = +0.34 V

Calculate E°cell for the reaction of nickel(II) ions with cadmium metal at 25°C. K = 1.17 × 105Ni2+(aq) + Cd(s) → Cd2+(aq) + Ni(s) Select one: a. 0.075 V b. 0.10 V c. 0.12 V d. 0.15 V e. 0.30 V

Which is strongest reducing agent? Zn2+(aq) + 2e- → Zn(s) Cu2+(aq) + 2e- → Cu(s) A. Zn2+(aq) B. Cu2+(aq) C. Cu(s)D. Zn(s)

140Ba decays by β- emission. What is the symbol for the element that results from this decay process?

Calculate the ratio [NH4+]/[NH3] needed in an ammonia/ammonium chloride buffer to produce a pH of 8.45.

6.46

Consider a sample of iodine-131.a. How many half-lives would it take for the sample to decay until less than 1% of the original isotope remained?a. How many days would this be?

6.6, 56.7 days

What is the pH of a buffer made by combining 0.10 mol of H2CO3 (Ka = 4.5 × 10-7) and 0.20 mol of NaHCO3 in a 3.0 L vessel. A. 7.35 B. 6.65 C. 6.05 D. 7.95

6.65

The base imidazole (Im) has a Kb of 9.8 x 10-8. Calculate the ratio of imidazole (Im) and its conjugate acid (HIm+) needed to prepare a pH 7.84 buffer solution?

7.1

The active ingredient in Milk of Magnesia, a commonly used laxative, is magnesium hydroxide. A 2.0-teaspoon sample of Milk of Magnesia was analyzed and required 18.26 mL of a 1.50 M hydrochloric acid for complete neutralization. Calculate the mass percent concentration of magnesium hydroxide in Milk of Magnesia given that the density of Milk of Magnesia is 1.1 g/mL

7.1 %

What is oxidation number of Cl atom in HClO?

max number of hydrogens + halogens= 2C+N+2

2C+N+2

Which combination will produce a precipitate? lead (II) acetate and sodium chloride sodium sulfate and potassium hydroxide ammonium nitrate and magnesium bromide calcium sulfide and sodium iodide two of the above three of the above All of the above

Which is stronger acid? A. HCOOHB. CH3CH2OH

Which is the most important factor in determining relative acid strength? A. Bond strength/bond length to H B. Partial charge on HC. Both are equally important

electrolytes

An aqueous solution of a strong electrolyte conducts electricity well. An aqueous solution of a nonelectrolyte does not conduct electricity. An aqueous solution of a weak electrolyte conducts electricity poorly.

Which is (are) a possible molecular formula(s) with valid Lewis structure(s) for a compound with a molecular ion peak at m/z 60? Maximum numbers of carbons in the molecules = [molecular weight - 14(N) - 35(Cl) - 79(Br)] / 12 Select one or more: a. C2H8N2 b. C3H8O c. C5 d. C4H12 e. C2H4O2

C3H8O, C2H4O2, C2H8N2

Which compound will give an M+ and M+2 peak with an intensity ratio of 1:1? Select one: a. CH3CH2Cl b. CH3NH2 c. CH3CO2H d. CH3CH2Br e. (CH3)2NCH2C≡N

CH3CH2Br

equilibrium

Equilibrium reaction is a reversible reaction.Equilibrium is dynamic because the forward and reverse reactions are occurring continuously. Equilibrium is reached when the rate of the reverse reaction equals the rate of forward reaction. Reaction quotient (Q) used at any time of the reactionEquilibrium constant, K only used when the reaction is at equilibrium.

Select all conditions is/are met at the equivalence point of the titration of a monoprotic weak base with a strong acid? Select one or more: a. The volume of acid added from the buret must equal the volume of base titrated. b. The concentration of acid added from the buret must equal the concentration of base titrated. c. The pH of the solution is less than 7.00. d. The pH of the solution is more than 7.00. e. The moles of acid added from the buret equals the initial moles of weak base. f. The pH of the solution is equal to 7.00.

The moles of acid added from the buret equals the initial moles of weak base., The pH of the solution is less than 7.00.

Oxidation numbers are generally written above the atomic symbol. For ionic substances, the oxidation number and the charge on the atomic ion are the same. The oxidation number is 0 in any neutral substance that contains atoms of only one element. (Al, Fe, H2, O2, O3, P4, and S8) The oxidation number is equal to the charge on the ion for ions that contain only a single atom. (Na+, Cl-) The oxidation number of H is +1 when it is combined with a more electronegative element. (CH4, NH3, H2O, and HCl) The oxidation number of H is -1 when it is combined with a less electronegative element. (LiH, NaH, CaH2, and LiAlH4) The elements of Groups 1 and 2 form compounds in which the metal atoms have oxidation numbers of +1 and +2, respectively.

The species that loses electrons is oxidized. This species is often referred to as the reducing agent. The species that increases in oxidation number. • The species that gains electrons is reduced. This species is often referred to as the oxidizing agent. The species that decreases in oxidation number.

What is the definition of molality?

mol solute/kg of solvent

Indicate whether each of the following statements is true or false A certain mass of solid Na contains fewer atoms than the same mass of gaseous Ne.Answer 1Choose...TrueFalse On average, one Li atom weighs 6.941 grams.Answer 2Choose...TrueFalse Every H atom weighs 1.008 amu.Answer 3Choose...TrueFalse The average atomic mass of an unknown monatomic gas is 0.045 g/mol.Answer 4Choose...TrueFalse A certain mass of solid Na contains fewer atoms than the same mass of gaseous Ar.Answer 5

true false false false false

solute qualitative effects-addition of solute to solvent

vapor pressure-reduces boiling point-increases freezing point/melting-decreases osmotic pressure- increases

Which combinations would produce a buffer solution? Select one or more: a. strong acid and its conjugate base b. weak base and its strong base c. weak acid and its conjugate base d. weak acid and its strong acid e. weak base and its conjugate acid f. strong base and its conjugate acid

weak acid and its conjugate base, weak base and its conjugate acid

The limiting reactant in a particular reaction can be recognized because it is the reactant that

would be used up first

Zinc, Zn, and iodine, I2, react to form zinc(II) iodide, ZnI2 (the reactants and the product are all solids at room temperature). Write a balanced chemical reaction for this process. Suppose that 50.0 g of zinc and 50.0 g of iodine are used to form zinc(II) iodide. Assuming that the reaction goes to completion, which element will be totally consumed in the formation of the zinc(II) iodide? What is the limiting reagent? How many grams of zinc(II) iodide can be produced? How many grams of the excess element remain unreacted?

zn + I2 =ZnI2 totally consumed=I2=limiting reagent 62.9 g ZnI2 produced unreacted: 37.12 g

Which temperature unit(s) can be used in boiling point and freezing point colligative property calculations? Select one or more: a. oC b. K c. oF

a, b

If Kc = 0.78 for the first reaction (K1), what is the Kc for the second reaction (K2) (at the same temperature)?

a. k1=.78 k2= .883 b. 1.13

Two tablespoons of table salt (34.12 g of sodium chloride) are added to 1.00 L of water (Kb = 0.51 °C/m and Kf = 1.86 °C/m). a. boiling point b. freezing point

a. 100.59 b.-2.17

Given a heating curve for 1.00 mole of substance Z below, what is molar heat of vaporization (Hvap) of the substance Z?

a. 400 kj/mol

Consider 500 mL of a sodium acetate/acetic acid buffer in which the concentration of sodium acetate is 0.50 M and that of acetic acid is 0.10 M. (Ka acetic acid = 1.7 × 10-5) What is the pH of this buffer? If 0.010 mol of strong base (NaOH) was added to the prepared buffer, how would the pH change? If 0.010 mol of strong acid (HCl) was added to the prepared buffer (ignore the changes which were made in question b), how would the pH change?

a. 5.47 b. 5.58 +.11 c. 5.37, -.10

Which is TRUE about equivalent point for titration of 0.1 M HCl with 0.1 M NaOH? A. mole of HCl = mole of NaOHB. volume of HCl = volume of NaOH C. pH = 7D. Two of the aboveE. All of the above

all the above

Which gas will have lowest average kinetic energy at 300 K: Ne, He, H2, and O2? Ne He H2 O2 All gases will have the same average kinetic energy

all will have same bc only depends on temp

conversions

amu/atom= g/6.022 x 10^23 atoms= g/mol -1 mol is 6.022 x 10^23 atoms/particles in grams -average mass of one atom in amu to average mass of one atom in grams= ____amu x 1.66054 x 10^-24g/1amu

Calculate the volume in mL of a 3.91 M KF (aq) solution that should be used to prepare 250. mL of 0.150 M KF(aq).

9.59 mL

The following reaction is spontaneous at standard conditions. I2(s) + 2Br- (aq) → Br2(l) + 2I- (aq) Select one: True False

false

Determine the freezing point of 1.4 kg of water (Kf = 1.86 degC/m) when 26.4 g of sodium chloride is added to it.

-1.2

information obtained by mass spectrometry

-exact mass of atoms -present of isotopes -proportion of each isotope -number of atoms or molecules present in a sample

What is the hydronium ion concentration of a 0.370 M acetic acid solution?

.0025 M

Kc = 150.0 at a certain temperature for the reaction: 2NO (g) + O2 (g) = 2NO2(g) What is the concentration of NO2 if the equilibrium concentration of NO and O2 are 1.00 × 10-3 and 5.00 × 10-2, respectively?

.0027 M or 2.7 x 10^-3 M

What is the hydronium ion concentration of a 0.487 M acetic acid solution?

.0029 M

AgCl is essentially insoluble in water. If a solution containing Ag+ ions is mixed with a solution containing Cl- ions, the following reaction occurs: Ag+(aq) + Cl-(aq) → AgCl(s) producing a solid precipitate of AgCl. How many moles of solid AgCl can be produced when 25.0 mL of a 0.125 molar NaCl solution is mixed with 35.0 mL of a 0.100 molar AgNO3 solution?

.003125 mol or 3.125 mol

Based on the information provided below: Moog 39 Table 1: The results (after equilibrium has been established) of adding solid Mg(OH)2 to 10.0 L of water at 25 °C. What is the maximum mass in g of Mg(OH)2 that can be dissolved in 1.00 L of water?

.00963 g

Calculate the mass of Ag2CO3(s) produced by mixing 125 mL of 0.315 M Na2CO3(aq) and 75.0 mL of 0.155 M AgNO3(aq) and the number of moles of the excess reactant remaining in solution.

.0336 mol

Determine the value of Kc for the following reaction A + 2B ↔ 2C if the equilibrium concentrations are found to be: A = 1.76 M B= 3.20 M C = 1.51 M

.127

Determine the number of moles of He if the temperature is 27.5 oC, the volume of the container is 4.25 liters, and the pressure of He is 594.5 torr. PV = nRT 1 atm = 760 torr R = 0.08206 L*atm / K*mol T (K) = T (oC) + 273.15 Include units and answer to 3 decimal places.

.135 moles

Determine the value of Kc for the following reaction A + 2B ↔ 2C if the equilibrium concentrations are found to be: A = 1.42 M B= 3.68 M C = 1.67 M

.145

A voltaic cell consists of a Ag/Ag+ electrode (E° = 0.80 V) and a Fe2+/Fe3+ electrode (E° = 0.77 V) with the following initial molar concentrations: [Fe2+] = 0.30 M; [Fe3+] = 0.10 M; [Ag+] = 0.30 M. What is the equilibrium concentration of Fe3+? (Assume the anode and cathode solutions are of equal volume, and a temperature of 25°C.) Select one: a. 0.030 M b. 0.043 M c. 0.085 M d. 0.11 M e. 0.17 M

.17 M

Determine the mass in grams of lead (II) iodide that will dissolve in 500.0 mL of a solution containing 1.03 grams of lead (II) nitrate. Ksp of lead (II) iodide is 1.4 x 10-8. Hint: Think about common ion effect.

.17 g

Calculate the molarity (M) of the excess reactant remaining in solution when mixing 103.7 mL of 0.364 M Na2CO3(aq) and 73.7 mL of 0.200 M AgNO3(aq) (molar mass of Ag2CO3 = 275.8 g/mole)

.171 M

Calculate the molarity (M) of the excess reactant remaining in solution when mixing 145.8 mL of 0.366 M Na2CO3(aq) and 79.6 mL of 0.138 M AgNO3(aq) (molar mass of Ag2CO3 = 275.8 g/mole)

.212 M

How many moles of sulfuric acid are found in 24.5 g of H2SO4?

.250

What is the hydronium concentration of a 0.27 M solution of sulfuric acid?

.27

Given the equilibrium reaction PCl5 (g) ↔ PCl3 (g) + Cl2 (g) Calculate the number of moles of Cl2 produced at equilibrium when 1.00 mol of PCl5 is heated at 287.2 deg celsius in a vessel having a capacity of 10.0L. At 287.2, K = 0.029 for this dissociation.

.413

Determine the value of Kc for the following reaction A + B ↔ 2C if the equilibrium concentrations are found to be: A = 0.840 M B= 1.338 M C = 0.69 M

.42

What is the hydronium concentration of a 0.43 M solution of sulfuric acid?

.43

If 21.5 mL of 2.1 M HCl are titrated with 1.9 M NaOH, what is the pH at 16.7 mL?

At 90 degrees C, the following equilibrium is established: H2(g) + S(s) ↔ H2S(g) Kc = 6.8 X 10-2 If 0.39 mol of hydrogen and 0.5 mol of sulfur are heated to 90 degrees C in a 1 L vessel, what will be the partial pressure of H2S at equilibrium? Give your answer with units as atm

.74 atm

Given the concentrations below, calculate the cell potential at 25 °C. 14H+ (aq) + Cr2O72- (aq) + 6I-(aq) → 3I2 (s) + 2Cr3+ (aq) + 7H2O(l)

.897 v

what percentage of chlorine atoms has a mass of 35.453 amu

0- this is just the average, none will be exactly this

What is the hydronium concentration of a 4.3E-6 M solution of hydrochloric acid?

0.00

Based on the information provided below: Moog 39 Table 1: The results (after equilibrium has been established) of adding solid Mg(OH)2 to 10.0 L of water at 25 °C. What is the maximum number of moles of Mg(OH)2 that can be dissolved in 1.00 L of water?

0.000165 or 1.65E-4 g

What mass in grams of barium sulfate (Ksp = 1 x 10-10) will dissolve completely in 401.4 mL of aqueous solution?

0.001 g

What is the hydroxide ion concentration of a 3.9 M NH3 solution?

0.0084 M

What is the pH of 0.1 M HCl? A. 14 B. 13 C. 7 D. 1 E. 2

Which are standard conditions for an electrochemical cell?1. Solutes in aqueous solution have a concentration of 1 M.2. Gaseous reactants or products have a pressure of 1 bar ≈ 1 atm.3. Solids are present in quantities of 1 mole. 4. Temperature is 298 K. Select one or more: a. 1 b. 2 c. 3 d. 4

1,2

The base imidazole (Im) has a Kb of 9.8 x 10-8. Calculate the ratio of imidazole (Im) and its conjugate acid (HIm+) needed to prepare a pH 7.37 buffer solution?

2.4

In a galvanic cell, the reduction potentials of two standard half-cells are 0.70V and -0.56 V. The predicted cell potential of the galvanic cell constructed from these two half-cells is Be sure to include the sign (- or +) and proper units in your answer.

1.26 V

How many moles of nitrogen gas, N2, are there in 35.7 g of nitrogen atoms? Answer with 3 significant figures with no unit

1.28

In an experiment you determined solubility of lead(II) sulfate in water is 0.037 g/L. Calculate the solubility product constant of lead(II) sulfate.

1.5e-8

When 1.0 g of AgCl is placed in a beaker containing 2.00 liters of water at room temperature, only a small amount of AgCl(s) is observed to dissolve. In fact, only 8.0 × 10-5 moles of AgCl are found to dissolve.Calculate the equilibrium constant, Ksp

1.6 x 10 ^-9

From the mass spectrum of Krypton (atomic number = 36) shown, determine the fractional abundance (%) of the isotope with mass of 82 amu. enter your answer as a percent e.g. 100% or 100 % peaks at 82, 82, 84, 86

10%

What is the pH of 0.1 M NH3? Kb of NH3 = 1.8 x 10-5 A. 11.13 B. 13.00 C. 7.00 D. 1.00 E. 2.87

11.13

Identify the atom from the given mass spectrum. a. Sm b. Eu c. B d. Br e. Cl

151 and 153 peaks both close to 100, Eu

Calculate the mass of Ag2CO3(s) produced by mixing 39.4 mole of CO32- (aq) and 11.6 mole of Ag+ (aq) and calculate the number of moles of the excess reactant remaining in solution. (molar mass of Ag2CO3 = 275.8 g/mole)

1599.4 g 33.6 mole in excess co32-

You are about to go on a trip for spring break, and you want to capture pictures of all your adventures. Before the trip your iPhone has 8.3 Gigabytes of free space. Each picture you take is 5.13 Megapixels. How many pictures can you take of your excellent adventure before your phone memory is full? (assume 1 pixel = 1 byte, and you can't upload your pictures to iCloud) You do not neet to enter units. Make sure to answer with 2 significant figures.

1600

How many grams of aluminum chloride can be produced from 1.82 moles of Cl2 and 2.39 moles of Al? The chemical equation is 3Cl2 + 2Al → 2AlCl3

162 g

How many grams of N2 (28.01 g/mole) can be obtained by reacting 24.5 g of NH3 (17.03 g/mole) with 30.8 g of O2 (MW = 32.00 g/mole)? 4NH3(g) + 3O2(g) →2N2(g) + 6H2O(l)

17.97 g

What mass of solid NaCH3CO2 should be added to 1.5 L of 0.6 M CH3CO2H to make a buffer with a pH of 5.14?

173.1 g

A 4.00-L flask containing 2.0 mol of O2 and 1.0 mol of N2 is in a room that is 22.0 °C. What is the total pressure? A. 3 atm B. 6 atm C. 12atm D. 18atm E. 24atm

18 atm

How many grams of aluminum chloride can be produced from 2.12 moles of Cl2 and 2.15 moles of Al? The chemical equation is 3Cl2 + 2Al → 2AlCl3

188 g

A mixture containing 9 mol of F2 and 5 mol of S is allowed to react as follows: 3F2 + S → SF6 How many moles of the excess reactant remains after the limiting reactant is consumed?

A voltaic cell employs the redox reaction: 2Fe3+(aq) + 3Mg(s) → 2Fe(s) + 3Mg2+ (aq) Calculate the cell potential at 25 deg C when the initial concentration of iron ions is 1.85 M and the initial concentration of magnesium ions is 0.00152 M.

2.419 V

Ammonia gas is synthesized according to the balanced equation below. N2(g) + 3 H2(g) → 2 NH3(g) If 1.35 L N2 react with 3.65 L H2, what is the theoretical yield (in liters) of NH3 at STP? Include units in your answer.

2.43 L

What is the pH of a buffer made from 0.50 M HF (Ka = 6.8 × 10-4) and 0.20 M NaF? A. 2.77 B. 11.23 C. 3.56 D. 10.43 E. 7.00

2.77

After an organism dies, it stops taking in radioactive carbon-14 from the environment. If the carbon-14:carbon-12 ratio (14C/12C) in a piece of petrified wood is one sixteenth of the ratio in living matter, how old is the rock? (Hint: How many half lives have elapsed?)

22920

What mass of solid NaCH3CO2 should be added to 1.7 L of 0.5 M CH3CO2H to make a buffer with a pH of 5.34?

259.1 g

A metal, M, forms an oxide having the formula M2O3 containing 52.92% metal by mass. Determine the atomic weight in g/mole of the metal (M). Please provide your answer in 2 decimal places.

26.98

When 1.000 mole of Na2SO4 is dissolved in water to make exactly one liter of solution: a. howmanymolesofsodiumionsarefoundinthesolution? how many moles of sulfate ions are found in the solution? what is the molarity of sodium ions in the solution? what is the molarity of sulfate ions in the solution?

2Na+ + 1so42- a. 2 moles na+ b. 1 mole so42- c. 2 moles na+/1l= 2M Na+ d. 1 mole so42/1l=1m so42-

Aqueous solutions of calcium chloride and sodium phosphate react to produce solid calcium phosphate and aqueous sodium chloride.When the chemical reaction is balanced, what is the coefficient in front of the calcium chloride?

In a galvanic cell, the reduction potentials of two standard half-cells are 2.61V and -0.60 V. The predicted cell potential of the galvanic cell constructed from these two half-cells is Be sure to include the sign (- or +) and proper units in your answer.

3.21 V

In a mixture of gases the total pressure, P , is the sum of the pressures of the individual gases, CTQ 3: Consider a mixture that has partial pressures of 525 torr of He and 363 torr of Ar. What is the total pressure of this mixture in torr and in atm? CTQ 6: Determine the number of moles of He and the number of moles of Ar present in the mixture from CTQ 3 given that the temperature is 27.5 °C and the volume of the container is 4.25 liters.

3: 1.17 atm 6: .119 mol He, .0823 mol Ar

If 25.7 mL of 2.6 M CH3COOH are titrated with 0.7 M NaOH, what is the pH at 14.8 mL?

4.0

If 27.3 mL of 1.3 M CH3COOH are titrated with 0.7 M NaOH, what is the pH at 12.8 mL?

4.3

What is the pH of the buffer that results when 20.6 g sodium acetate (NaCH3CO2) is mixed with 431.8 mL of 1.6 M acetic acid (CH3CO2H) and diluted with water to 1.0 L?

4.33

What is the pH of the buffer that results when 20.6 g sodium acetate (NaCH3CO2) is mixed with 459.4 mL of 1.4 M acetic acid (CH3CO2H) and diluted with water to 1.0 L

4.34

Two gases are added to a 1.00 L container: 2.0 moles of A; 4.0 moles of B. These gases react as follows: A(g) + 3 B(g) ⇔ C(g) + 2 D(g) At equilibrium the container contains 0.4 moles of D. Calculate the value of the equilibrium constant for this reaction.

4.5 x 10-4

What is the pH of the buffer that results when 25.8 g sodium acetate (NaCH3CO2) is mixed with 335.3 mL of 1.7 M acetic acid (CH3CO2H) and diluted with water to 1.0 L?

4.51

What is the pH of the buffer that results when 47.1 g sodium acetate (NaCH3CO2) is mixed with 655.4 mL of 1.3 M acetic acid (CH3CO2H) and diluted with water to 1.0 L?

4.60

A solution was prepared by dissolving 0.0217 mole of propionic acid and 0.0194 mole of sodium propionate in 1.00 L? What would be the pH of the solution in beaker after 1.68 mL of 0.0196 M HCl were added to 10.0 mL of the prepared solution?

4.70

A solution was prepared by dissolving 0.0195 mole of propionic acid and 0.0170 mole of sodium propionate in 1.00 L? What would be the pH of the solution in beaker after 1.93 mL of 0.0106 M HCl were added to 10.0 mL of the prepared solution?

4.73

A solution was prepared by dissolving 0.0215 mole of propionic acid and 0.0194 mole of sodium propionate in 1.00 L? What would be the pH of the solution in beaker after 1.22 mL of 0.0193 M HCl were added to 10.0 mL of the prepared solution?

4.74

What is the pH of the buffer that results when 42.0 g sodium acetate (NaCH3CO2) is mixed with 392.2 mL of 1.1 M acetic acid (CH3CO2H) and diluted with water to 1.0 L?

4.84

A rancher protesting in Oregon is looking for the U.S. government to give him a piece of land that is 3 miles long by 2 miles wide. How many acres is the rancher expecting to receive? 1.00 acre = 43560 square feet You do not neet to enter units. Make sure to answer with 1 significant figures.

4000

For the reaction: N2 + 3 H2 → 2NH3 Calculate the number of grams of NH3 formed when 2.79 mol of N2 is treated with 3.77 mol H2.

42.8 g

The combustion of 0.0272 mole of a hydrocarbon produces 1.9609 g H2O and 3.5927 g CO2. What is the molar mass of the hydrocarbon in g/mole unit? Please answer with 2 significant figures.

titanium has five naturally occuring elements. The reported mass of all the isotopes are: % natural abundance Atomic mass 7.930 45.96 7.280 46.95 73.94 47.95 5.510 48.95 5.340 49.95 Based on this data, what is titanium's average atomic mass? (make sure to answer with 2 decimal places and unit

47.88 amu

Calculate the pH of a solution 0.250 M in acetic acid and 0.500 M in sodium acetate.

5.07

Consider a 100-gram sample of radioactive cobalt-60. How much time will it take before half the sample has decayed? Approximately how many grams of radioactive cobalt-60 will remain after 11 years?

5.3 years 23.7 g

Calculate the equilibrium constant for the following reaction at 25.4 °C, 2 IO3-(aq) + 5 Hg(l) + 12 H+(aq) → I2(s) + 5 Hg2+(aq) + 6 H2O(l)

5.5e68

Chromium has four naturally occuring elements. The reported mass of all the isotopes are: fractional abundance Atomic mass 0.04350 49.9461 0.8379 51.9405 0.09500 52.9407 0.02360 53.9389 Based on this data, what is chromium's average atomic mass? (make sure to answer with 2 decimal places and unit)

51.99 amu

What mass of solid NaCH3CO2 should be added to 2.0 L of 0.8 M CH3CO2H to make a buffer with a pH of 5.39?

546.94 g

An equilibrium mixture of PCl5, PCl3, and Cl2, at a certain temperature in a 5.0 L container consists of 0.80 mole PCl5, 0.55 mole PCl3, and 1.2 mole Cl2. Calculate Kc for the reaction:

6.06

A 0.600 mol sample of Cu2S is roasted in excess oxygen to yield copper metal and sulfur dioxide. Calculate the mass of copper metal produced. Cu2S + O2 → 2Cu + SO2 Need to answer with units on this question. For example if the answer is 111 grams you can write: 111 g 1.11e2 g

76.3 g

Exactly 13.4 mL of 0.4 M HNO2 are titrated with a 0.4 M NaOH solution. What is the pH at the equivalence point ?

8.3

Exactly 71.4 mL of 0.5 M HNO2 are titrated with a 0.5 M NaOH solution. What is the pH at the equivalence point ?

8.4

Exactly 31.0 mL of 0.2 M HNO2 are titrated with a 0.2 M NaOH solution. What is the pH at the equivalence point ?

8.67

The first step in the manufacturing process of phosphorous is the reaction below: 2Ca3(PO4)2(s) + 6SiO2(s) → 6CaSiO3(s) + P4O10(g) The MW of Ca3(PO4)2(s) is 310.2 g/mole and the MW of SiO2(s) is 60.1 g/mole. If 20.0 g of Ca3(PO4)2(s) and 20.0 g of SiO2(s) are reacted, how many grams of P4O10(g) can be produced?

9.14 g

Calculate the equilibrium constant for the following reaction at 24.4 °C, 2 IO3-(aq) + 5 Hg(l) + 12 H+(aq) → I2(s) + 5 Hg2+(aq) + 6 H2O(l)

9.4e68

What is the Ksp of MX2 if its solubility in water is 1.6 x 10-4 M? A. 1.6 x 10-11 B. 2.6 x 10-8 C. 3.2 x 10-4 D. 4.1 x 10-12

A. 1.6

Based on the titration curve of 0.12 g of acid in 50 mL water, what is the molecular weight and identity of the acid in this titration with 0.1 M NaOH? a. Acetic acid (CH3COOH)b. Nitrous acid (HNO2)c. Benzoic acid (C6H5COOH) d. Hydrocyanic acid (HCN) e. Hydrofluoric acid (HF)

A. acetic acid

The half-life for metastable Barium-137 is about 2.5 minutes. After 15 minutes of generating Barium-137, what percentage of gamma radioactivity is left in a sample? A. 50% B. 25% C. 12.5% D. 6.25% E. 2.78% F. 1.56%

Which of the following 1.0 m aqueous solutions would cause the largest change in freezing point? A. Na2SO4 B. KC2H3O2 C. C12H22O11 D. Mg(NO3)2

a and d bc I=3

If the ratio of base to acid in a buffer increases by a factor of 10, the pH of the buffer Select one: a. increases by 1. b. decreases by 1. c. remains unchanged. d. increases by 10. e. decreases by 10.

If the volume of a confined gas is expanded to four times the original volume while its temperature remains constant, what change will be observed? Select one: a. The pressure of the gas will decrease to 1/4 its original value. b. The pressure of the gas will decrease to 1/2 its original value. c. The pressure of the gas will remain unchanged. d. The pressure of the gas will increase to twice its original value. e. The pressure of the gas will increase to four times its original value.

Magnesium hydroxide [ Mg(OH)2 ] is a common component of antacids. Mg(OH)2 is often known as milk of magnesia, because of its milk-like appearance as a suspension. What would you expect the solubility of Mg(OH)2 to be in patient stomach at pH 1.5-3.5? Select one: a. Solubility of Mg(OH)2 increases b. Solubility of Mg(OH)2 decreases c. Solubility of Mg(OH)2 will be the same

One kind of battery used in watches contains mercury(II) oxide. As current flows, the mercury(II) oxide is reduced to mercury.HgO(s) + H2O() + 2 e- → Hg() + 2 OH-(aq)If 2.3 x 10-5 amperes flows continuously for 1200 days, what mass of Hg() is produced? Select one: a. 2.5 g b. 5.0 g c. 9.9 g d. 13 g e. 15 g

The following reaction occurs spontaneously.2 Fe(s) + 3 Cl2(aq) → 2 Fe3+(aq) + 6 Cl-(aq)Write the balanced oxidation half-reaction. Select one: a. Fe(s) → Fe3+(aq) + 3e- b. Fe(s) + 3 e-→ Fe3+(aq) c. Fe(s) + 3/2 Cl2(aq) → FeCl3(aq) d. Cl2(aq) → 2 Cl-(aq) + 2 e- e. Cl2(aq) + 2 e- → 2 Cl-(aq)

What is the pH of a 0.20 M Ca(OH)2 solution? Select one: a. 13.60 b. 0.40 c. 13.40 d. 7.00 e. 0.60

What is the temperature and presure at STP? Select one: a. 0°C and 1 atm b. 25°C and 1 atm c. 0°C and 0 atm d. 25°C and 0 atm e. 273.15 °C and 1 atm

What mass of Na2SO4 must be dissolved in 430.3 grams of water to lower the freezing point by 3.59 ºC? The freezing point depression constant, Kfp, of water is 1.86 ºC/m. Assume the van't Hoff factor for Na2SO4 is 2.85. Select one: a. 41.40 b. 41400.02 c. 0.22 d. 0.00

When 3.00 moles sodium sulfate is dissolved in water to make exactly ten liters of solution, what is the molarity of the sodium ions in the solution? Select one: a. 0.600 M b. 6.00 M c. 3.00 M d. 0.300 M

Which compound will give an M+ and M+2 peak with an intensity ratio of 3:1? Select one: a. CH3CH2Cl b. CH3NH2 c. CH3CO2H d. CH3CH2Br e. (CH3)2NCH2C≡N

Which compound will give an M+2 peak? Select one: a. CH3CH2Cl b. CH3NH2 c. CH3CO2H d. CH3CH2NH2 e. (CH3)2NCH2C≡N

Which do you expect to be the strongest acid? Select one: a. PH4+ b. NH4+

Which is more concentrated with respect to sodium ions: A. 0.30 M Na2SO4 B. 0.50 M NaCl

Which is more concentrated with respect to sodium ions: A. 50.0 g of NaCl in 500.0 mL of solutionB. 50.0 g of Na2SO4 in 500.0 mL of solution

Which isotope has the shortest half-life? Select one: a. A-closest- blue line b. B green c. C red d. D purple furthest

Which pair of compounds gives a precipitate when aqueous solutions of them are mixed? Assume that the concentrations of all compounds are 1.0 M immediately after mixing. Select one: a. NiBr2 and K2CO3 b. HNO3 and NH4I c. BaCl2 and KClO4 d. Na2CO3 and H2SO4 e. KCl and KNO3

Which statement explains why HBr is a stronger acid than HF? Select one: a. Br- is more stable than F- because Br- is larger than F-. b. Br- is less stable than F- because Br- is larger than F-. c. Br- is more stable than F- because Br- is less electronegative than F-. d. Br- is less stable than F- because Br- is less electronegative than F-.

hich of these expressions is a constant? Select one: a. [H3O+] x [OH-] b. [H3O+] - [OH-] c. [H3O+]/[OH-] d. [H3O+] + [OH-]

A certain galvanic cell has for its spontaneous cell reaction: Zn + HgO ↔ ZnO + Hg Which is the half-reaction occurring at the cathode? Select one: a. Zn2+ + 2 e- → Zn b. HgO + 2 e- → Hg + O2- c. ZnO + 2 e- → Zn d. Zn →Zn2+ + 2 e-

A solution was prepared by dissolving 0.0200 mole of propionic acid and 0.0100 mole of sodium propionate in 1.00 L of water. Calculate pH of the solution after 10.00 mL of 0.100 M HCl were added to the prepared solution.

A solution was prepared by dissolving 0.0200 mole of propionic acid and 0.0100 mole of sodium propionate in 1.00 L of water.Calculate pH of the solution after 10.00 mL of 0.100 M HCl were added to the prepared solution. Select one: a. 4.585 b. 4.518 c. 4.886 d. 4.645 e. 5.254 f. 5.123

Al3+ is reduced to Al(s) at an electrode. If a current of 2.75 ampere is passed for 36 hours, what mass of aluminum is deposited at the electrode? Select one: a. 9.2 x 10-3 g b. 3.3 x 101 g c. 9.9 x 101 g d. 1.0 x 102 g e. 3.0 x 102 g

For the reaction: Zn(s) + Cu2+(aq) ---> Zn2+(aq) + Cu(s), which species is oxidizing agent? Select one: a. none b. Cu2+(aq) c. Cu(s) d. Zn2+(aq) e. Zn(s)

If 0.50 L of a buffer containing 1.0 mol H2PO4- and 1.0 mol HPO42- is diluted to a volume of 5.0 L, the pH Select one: a. decreases by 10. b. remains unchanged. c. increases by 1. d. increases by 10. e. decreases by 1.

If 0.50 L of a buffer containing 1.0 mol H2PO4- and 1.0 mol HPO42- is diluted to a volume of 5.0 L, the pH Select one: a. increases by 1. b. remains unchanged. c. increases by 10. d. decreases by 10. e. decreases by 1.

Nitric oxide is made from the oxidation of ammonia. What mass of nitric oxide can be made from the reaction of 8.00 g NH3 with 17.0 g O2?4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(g) Select one: a. 4.54 g b. 12.8 g c. 14.1 g d. 15.9 g e. 25.0 g

The equilibrium constant reaction (Kc) for the reaction below is 0.12. 2 SO3(g) 2 SO2(g) + O2(g)If a flask is filled with 0.1 M SO3, 0.08 M SO2, and 0.16 M O2, predict the direction of the equilibrium as the reaction is reaching equilibrium by using Q, the reaction quotient. Select one: a. Forward because Q > K. b. Forward because Q < K. c. Reverse because Q < K. d. Reverse because Q > K. e. The reaction is at equilibrium because Q = K.

The metal molybdenum, Mo(s), reacts to form MoO2(s). The half-reaction equation that explains the change in oxidation state of molybdenum can be written as Select one: a. Mo2+(aq) → Mo4+(aq) + 2e- b. Mo(s) → Mo4+(aq) + 4e- c. Mo2+(aq) + 2e- → Mo(s) d. Mo4+(aq) + 4e- → Mo(s) e. Mo(s) + 2e- → Mo2+(aq)

The rate constant for the decay of copper-66 is 5.1 minutes-1. What is the half-life of this isotope? Select one: a. 5.1 min b. 0.14 min c. 10.2 min d. 0.20 min e. 2.6 min

What is the change in mass number when a beta particle is emitted from a nuclide? Select one: a. -2 b. 0 c. +1 d. -4 e. -1

What is the coefficient for HCl(g) when the chemical reaction is balanced? Fe2S3(s) + HCl(g) → FeCl3(s) + H2S(g) Select one: a. 3 b. 6 c. 5 d. 2 e. 1 f. 4

What is the effect of adding carbon on the system described below? 2C(s) + O2(g) ↔ 2CO(g) Select one: a. Shifts towards products b. remains unchanged c. Shifts towards reactants

What is the mole fraction of calcium chloride in 3.35 m CaCl2(aq)? The molar mass of CaCl2 is 111.0 g/mol and the molar mass of water is 18.02 g/mol. Select one: a. 0.000866 b. 0.0569 c. 0.271 d. 37.2 e. 59.2

What is the qualitative effect that the addition of a solute has on the boiling point of a solvent? Select one: a. no effect b. increases boiling point c. decreases boiling point

Which is the symbol for positron emission? Select one: a. 0-1e or β b. 0+1e or β+ c. 42He or α d. γ e. 10n

Which is true for an electrolytic cell? Select one: a. The reaction is at equilibrium. b. The reaction is non-spontaneous. c. The reaction is spontaneous.

Which of the following statements about the base peak of a mass spectrum is always true? Select one: a. The base peak corresponds to the molecular ion. b. The base peak corresponds to the most abundant ion. c. The base peak corresponds to the lowest m/z. d. None of the above.

Which salt is more soluble? Select one: a. AgCl (Ksp = 1.8 x 10-10) b. Ag2CrO4 (Ksp = 1.1 x 10-12)

You have two flasks of equal volume. Flask A contains H2 at 0 ºC and 1 atm pressure. Flask B contains CO2 gas at 25 ºC and 2 atm pressure. Which flask contains gas molecules with higher average kinetic energy per molecule? Select one: a. Both flasks have the same average kinetic energy. b. Flask B c. Flask A

A 1.367 g sample of an organic compound was combusted in a stream of air to yield 3.002 g carbon dioxide and 1.640 g water. If the original compound contained only C, H and O, what is its empirical formula? provide your answer as: C#H#O#

c3h8o

presence of Br or Cl

br-79 and 81, 1:1 ratio cl 35 and 37, 3:1 ratio -2 peaks, one molecule

A balloon is filled with He gas to a volume of 2.10 L at 35 °C. The balloon is placed in liquid nitrogen until its temperature reaches -196 °C. Assuming the pressure remains constant, what is the volume of the cooled balloon? Select one: a. -0.375 L b. 0.375 L c. 0.525 L d. 0.00909 L e. 8.40 L

A tightly sealed 4.0-L flask contains 884 torr of N2 at 94.0 °C. The flask is cooled until the pressure is reduced 442 torr. What is the temperature of the gas? Select one: a. -47.0 °C b. 47.0 °C c. -89.5 °C d. 184 °C e. 188 °C

Calculate the energy in the form of heat (in kJ) required to change 75.0 g of liquid water at 27.0 °C to ice at -20.0 °C. Assume that no energy in the form of heat is transferred to the environment. (Heat of fusion = 333 J/g; heat of vaporization = 2256 J/g; specific heat capacities: ice = 2.06 J/g·K, liquid water = 4.184 J/g·K) Select one: a. -13.4 kJ b. -17.7 kJ c. -36.5 kJ d. -10.2 kJ e. -30.3 kJ

Calculate ΔG°for the reaction of iron(II) ions with one mole of permanganate ions.MnO4-(aq) + 8H+(aq) + 5e- → Mn2+(aq) + 4H2O(l); E° = 1.51 VFe3+(aq) + e- → Fe2+(aq); E°= 0.77 V Select one: a. -71.4 kJ b. -286 kJ c. -357 kJ d. -428 kJ e. None of these choices is correct.

For the galvanic cell, Zn(s) + Cu2+(aq) ↔ Zn2+(aq) + Cu(s), which species is the anode? Select one: a. Cu(s) b. Zn2+(aq) c. Zn(s) d. Cu2+(aq)

For the reaction: Zn(s) + Cu2+(aq) ---> Zn2+(aq) + Cu(s), which species is reduced? Select one: a. Zn(s) b. Cu(s) c. Cu2+(aq) d. none e. Zn2+(aq)

The half-life for Barium-137 is 2.5 minutes. How much Barium-137 in μCi would you have in your sample after 2 min if you are starting with 1 μCi of Barium-137? A. 2.00 μCi B. 0.50 μCi C. 0.57 μCi D. 0.67 μCi E. 1.00 μCi

The solubility of PbI2 in water is 0.62 g in 1.0 L of water at 25 °C. What is the value of Ksp for PbI2? Select one: a. 8.4 x 10-10 b. 2.4 x 10-9 c. 9.7 x 10-9 d. 1.8 x 10-6 e. 0.95

What is the effect of reducing the volume on the system described below? 2C(s) + O2(g) ↔ 2CO(g) Select one: a. Remains unchanged b. Shifts towards products c. Shifts toward reactants.

What is ΔGo for this reaction? (ΔGo = -nFEo, where F = 96,485 C/mol) Pb2+(aq) + Cu(s) → Pb(s) + Cu2+(aq) Select one: a. 40.7 kJ b. -40.7 kJ c. 89.3 kJ d. -89.3 kJ

Which one of the following metals would be most likely to oxidize if a clean surface of the metal were exposed to the atmosphere? Select one: a. iron b. gold c. aluminum d. zinc e. silver

Which species is the conjugate base of the hydronium ion, H3O+? Select one: a. H3O b. H2O- c. H2O d. HO-

Acetylene gas, HCCH, is commonly used in high temperature torches. Write a chemical equation for the reaction of acetylene with hydrogen gas (H2) to form ethane (C2H6). How many grams of ethane can be produced from a mixture of 30.3 grams of HCCH and 4.14 grams of H2?

c2h2 +2h2=c2h6 31.8 g

The empirical formula for a molecule is C19H36NO6 and its molar mass is 748.51 g/mol. What is the molecular formula?

c38h72n2o12

Propose three possible molecular formulas for a compound with a molecular ion at m/z 73.

c4h11n c3h7no c2h3no2

2. An aliphatic chiral compound gave a mass spectrum shown below in which the molecular ion appears in low intensity peaks at m/z = 92 & m/z = 94. Small fragment ion peaks are seen at m/z = 77 & 79 and at m/z = 63 & 65 (in the intensity of 3:1 ratio). Large fragment ions are seen at m/z = 57 (base peak). Suggest a molecular formula and name for this compound.

c4h9cl

Which compound(s) will be insoluble in water? Select one or more: a. lead (II) carbonate b. lead (II) acetate c. sodium carbonate d. calcium phosphate e. ammonium sulfate

calcium phosphate, lead (II) carbonate

Hydroxyurea (CH4O2N2) is a useful molecule. A single hydroxyurea molecule can be formed from the reaction of: 1 carbon dioxide molecule (CO2) 1 nitrogen molecule (N2)2 hydrogen molecules (H2) Provide a balanced chemical reaction for the production of hydroxyurea. Calculate the mass of hydroxyurea that can be produced from 416 grams of carbon dioxide, 142 grams of nitrogen molecules, and 58.2 grams of hydrogen molecules.

ch4o2n2 385.22 g of ch2o2n2

Which is strongest oxidizing agent? A. Ni2+B. Fe3+C. I2D. O2E. Cr2O72- F. Cl2

cl2

While running a new reaction, a chemist notices the evolution of a gas. A sample of this gas gave a mass spectrum in which the molecular ion (m/z = 44) was the largest ion peak. The only other significant peaks were observed at m/z = 28 & m/z = 16. What is this gas?

co2

If you have HOCN, what other component is necessary to make a buffer? A. NaOCN B. NH4OCN C. HClD. HCNE. NaCN F. NH4CN

conjugate base, A

Assuming ideal behavior, which of the following aqueous solutions should have the highest boiling point? Select one: a. 0.50 m Ca(NO3)2 b. 0.75 m NaCl c. 1.00 m LiBr d. 0.75 m K2SO4 e. 1.25 m C6H12O6

Assuming ideal behavior, which of the following solutions should have the lowest freezing point? Select one: a. 1.0 m RbBr(aq) b. 1.0 m NH3(aq) c. pure H2O d. 1.0 m MgCl2(aq) e. 1.0 m C6H12O6(aq)

By what (single step) process does osmium(Os)-185 change to rhenium(Re)-185? Select one: a. α particle emission b. β particle emission c. gamma ray emission d. electron capture e. neutron capture

For the reaction: PCl3(g)+Cl2(g) ⇌ PCl5(g), Kc=1.00×103 A 5.00-liter box at 25 °C has 0.0500 moles of PCl3(g), 0.0200 moles of Cl2(g), and 0.200 moles of PCl5(g). Predict which of the following will happen to the moles of PCl5 after injection of more moles of PCl3 into the system. Select one: a. No change in the moles of PCl5 because the system is at equilibrium. b. PCl5 will be consumed to form more PCl3 and Cl2. c. Cannot be predicted d. PCl3 and Cl2 will be consumed to form more PCl5.

Identify the atom from the given mass spectrum. 79% 10% 11%, 24 25 26 Select one: a. Mn b. Al c. Fe d. Mg e. Cr

If 5.00 g Br2 and 1.10 g NH3 react according to the equation below, what is the maximum mass of ammonium bromide produced?3 Br2() + 8 NH3(g) ® 6 NH4Br(s) + N2(g) Select one: a. 3.06 g b. 6.13 g c. 12.9 g d. 4.74 g e. 8.43 g

If Q > K, which direction will a reaction proceed to reach equilibrium? Select one: a. no change in direction b. forward c. impossible to determine without knowing the equilibrium constant value d. reverse

The base peak in a mass spectrum corresponds to the most stable fragment. Propose a structure for a compound that is consistent with the following data.a) The molecular ion peak has m/z = 116b) The base peak is at m/z = 59.c) The compound is composed of C, H and O atoms.d) The IR spectrum shows a strong absorbance at 3257 cm-1. Select one: a. I b. II c. III d. IV

The half-life of carbon-14 is 5730 years. If a sample initially contains 2.67 mg carbon-14, what mass remains in the sample after 2.40 x 104 years? Select one: a. 0.0 mg b. 0.17 mg c. 0.92 mg d. 0.15 mg e. 0.64 mg

What is Eocell for this reaction? Pb(s) + Cu2+(aq) → Pb2+(aq) + Cu(s) Standard Reduction Potentials Pb2+(aq) + 2e- → Pb(s) Eored = -0.126 V Cu2+(aq) + 2e- → Cu(s) Eored = 0.337 V Select one: a. -0.211 V b. -0.463 V c. 0.211 V d. 0.463 V

What is the molar solubility of AgCl in 0.033 M KCl(aq) at 25 °C? Ksp of AgCl = 1.8 x 10-10 Select one: a. 7.4 x 10-5 mol/L b. 1.8 x 10-10 mol/L c. 1.3 x 10-5 mol/L d. 5.5 x 10-9 mol/L e. 5.9 x 10-12 mol/L

What is the oxidation number of chromium in CrO42-? Select one: a. -2 b. -6 c. +2 d. +6 e. 0

What is the pH after 25.2 mL of 3.5 M NaOH have been added to 25.00 mL of 4.2 M HF? Select one: a. 7.00 b. 13.5 c. 1.76 d. 3.89 e. 14.5

What is the pH of a 0.75 M NaF solution? Select one: a. 5.48 b. 1.73 c. 12.27 d. 8.52

What is the pH of a solution that results from diluting 0.20 mol acetic acid (CH3CO2H) and 0.30 mol sodium acetate (NaCH3CO2) with water to a volume of 1.0 L? Select one: a. 4.35 b. 4.59 c. 4.77 d. 4.95 e. 5.14

What is the value of the constant for the expression that you chose in question 1? Select one: a. 1.0 × 10-7 b. 1.0 × 107 c. 1.0 × 1014 d. 1.0 × 10-14

What mass of Na2SO4 must be dissolved in 342.2 grams of water to lower the freezing point by 4.04 ºC? The freezing point depression constant, Kfp, of water is 1.86 ºC/m. Assume the van't Hoff factor for Na2SO4 is 2.85. Select one: a. 0.32 b. 37050.68 c. 0.00 d. 37.05

What mass of iron can be produced from the reaction of 175 kg Fe2O3 with 385 kg CO? Fe2O3(s) + 3 CO(g) → 2 Fe(s) + 3 CO2(g) Select one: a. 2.19 kg b. 30.6 kg c. 61.2 kg d. 122 kg e. 512 kg

When mixed in appropriate amounts, each of the following mixtures can produce an effective buffer solution EXCEPT Select one: a. NaHCO3 and Na2CO3 b. NaH2PO4 and Na2HPO4 c. HCl and NaH2PO4 d. NaOH and NaF e. Na2HPO4 and Na3PO4

Which compound is the weakest acid? Select one: a. H2S b. PH3 c. HCl d. SiH4

Which element or ion is the best reducing agent? Select one: a. Pd2+(aq) b. Pd(s) c. Br2(aq) d. H2(g) e. NO3-(aq)

Which statement about acid strength is true? Select one: a. The stronger the acid, the further the equilibrium lies to the left. b. The stronger the acid, the smaller the Ka. c. The stronger the acid, the larger the pKa. d. The stronger the acid, the smaller the pKa.

Which statement explains why H2O is a stronger acid than CH4? Select one: a. H2O can form hydrogen bonds while CH4 cannot. b. H2O forms a less stable conjugate base, HO-. c. CH4 forms a more stable conjugate base, CH3-. d. H2O forms a more stable conjugate base, HO-.

Which combination would be best to buffer an aqueous solution at a pH of 7.0? Select one: a. H3PO4 and H2PO4- b. HNO2 and NO2- c. CH3CO2H and CH3COO- d. H2PO4- and HPO42- e. NH4+ and NH3

d H2PO4- and HPO42-

The following reaction is spontaneous at standard conditions. I2(s) + 2Br- (aq) → Br2(l) + 2I- (aq)

false

If 0.10 M aqueous solutions are prepared of each of the acids, which produces the solution with the lowest pH? Select one: a. formic acid b. nitrous acid c. hydrocyanic acid d. hydrogen sulfite ion e. phosphoric acid

The compound P4S3 is used in matches. It reacts with oxygen to produce P4O10 and SO2. The unbalanced chemical equation is shown below.P4S3(s) + O2(g) → P4O10(s) + SO2(g)What mass of SO2 is produced from the combustion of 0.401 g P4S3? Select one: a. 0.134 g b. 1.20 g c. 0.0389 g d. 0.117 g e. 0.350 g

What is the mass percent of acetic acid in 12.3 m CH3CO2H(aq)? The molar mass of CH3CO2H is 60.03 g/mol and the molar mass of water is 18.02 g/mol. Select one: a. 0.718% b. 7.17% c. 11.5% d. 30.3% e. 42.4%

What is the pH of a buffer made from 0.50 M HF (Ka = 6.8 × 10-4) and 0.20 M NaF? Select one: a. 10.43 b. 3.56 c. 11.23 d. 7.00 e. 2.77

Which element or ion is the best oxidizing agent? Select one: a. Pd2+(aq) b. Pd(s) c. Br2(aq) d. H2(g) e. O3(g)

Which gas has the greatest density at 25 °C and 1 atm? Select one: a. O2 b. Ar c. N2 d. F2 e. C3H8

Select all conditions is/are met at the equivalence point of the titration of a monoprotic weak base with a strong acid? Select one or more: a. The pH of the solution is equal to 7.00. b. The pH of the solution is more than 7.00. c. The concentration of acid added from the buret must equal the concentration of base titrated. d. The volume of acid added from the buret must equal the volume of base titrated. e. The pH of the solution is less than 7.00. f. The moles of acid added from the buret equals the initial moles of weak base.

e, f

What would happen to the equilibrium reaction if temperature was increased : 2 NH3(g) ⇌ N2(g) + 3 H2(g) ΔH = + 92.2 kJ

eq. shifts to produce more products

T/F: The M peak in a mass spectrum is always the base peak.

false

equal masses of gaseous N2 and Ar are placed in separate flasks of equal volume at the same temperature. Tell whether the following statements is true or false. Statement: The Ar atoms have a greater speed than the N2 molecules. Select one: True False

false

Which acid will produce the lowest [H3O+] in a solution of a given molarity of acid? CH3COOH (Ka = 1.75 x 10-5) H2CO3 (Ka = 4.5 x 10-7) HI(Ka =3.0x109) HNO3 (Ka = 28) HNO2 (Ka = 5.1 x 10-4)

h2co3

In a redox reaction, the species whose oxidation number increases: Select one or more: a. is referred to as the reducing agent. b. is being reduced. c. is referred to as the oxidizing agent. d. is being oxidized.

is being oxidized., is referred to as the reducing agent.

A compound gave on analysis the following percent composition:K = 26.57%Cr= 35.36%O= 38.07% What is the emperical formula for this compound?

k2cr2o7

Under which conditions does a gas behave most ideally?

low pressure high temp

An antiseptic solution contains hydrogen peroxide, H2O2, in water. The solution is 0.907 m H2O2 and has a density of 1.03 g/mL. Calculate the other concentrations (mass percent, mole fraction, molarity, and ppm) of H2O2 in this solution.

mass %=3% mole fraction: .0161 molarity: .906 mole/L ppm: 30,840 mg/L or ppm

Which quantity unit(s) can be used for initial amounts of chemicals in the RICE table? A. moleB. molarity (M)C. atmD. Two of the above E. All of the above

mole and molarity

A student determines experimentally that the molar mass of the unknown compound in Model 2 is 92 grams/mole. What is the molecular formula of the compound?

n2o4 empirical forumla: NO2 mass of empirical formula: 46 molecular mass: 92 n=92/46=2 2xNO2= n2o4

Calculate the cell potential, at 25 °C, based upon the overall redox reaction below if [Zn2+] = 1.50 ́ 10-4 M, [Fe3+] = 0.0200 M, and [Fe2+] = 0.0100 M. Zn2+(aq) + 2 Fe2+(aq)Zn(s) + 2 Fe3+(aq) The standard reduction potentials are as follows: Zn2+(aq) + 2 e-Zn(s) E° = -0.763 V Fe3+(aq) + e-Fe2+(aq) E° = +0.771 V

n=2e-

A 5.00-liter box at 25 °C has 0.0500 moles of PCl3(g), 0.0200 moles of Cl2(g), and 0.200 moles of PCl5(g). A needle is inserted into the box described above and an additional 0.0600 moles of PCl3 are injected into the reaction mixture. Calculate the equilibrium concentrations of PCl3, Cl2, and PCl5.

pcl3- .0201 cl2- .0021 pcl5- .0419 M

Write systematic nomenclature for the following molecule HClO4

perchloric acid

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