Chem Sem 2

What is the percentage yield if 200. g of Cl2 react with an excess of KBr to produce 410. g of Br2? Cl2 + 2KBr → 2KCl + Br2 The atomic masses are: Chlorine, Cl, 35.45 amu, Bromine, Br, 79.90 amu, Potassium, K, 39.10 amu Show or describe the calculations required to solve the problem Your Answer:

91% 2.8 moles = 450 grams of Bromine 410/450 = 915

Which of the following expressions relates the kelvin and Celsius temperature scales? K = 273.15°C °C + 273.15 K K= -273.15 + °C K = 273.15 + °C

K = 273.15 + °C

Br2 is _______________In the reaction represented by the equation 2Na + Br2 ⟶ 2NaBr

Reduced On the left side of the arrow, Br2 has an oxidation number of 0 and on the right side of the arrow, Br has an oxidation number of -1; since the oxidation number went down from the left to right, Br is being reduced.

The sequence of steps in a reaction process is called the____.

reaction mechanism

In the reaction represented by the equation 2Na + Cl2 → 2NaCl, the Cl is

reduced.

What is the role of Zn in the reaction represented by the equation 2 Zn + O2 ⟶ 2 ZnO

reducing agent Zn is going from 0 on the left to +2 on the right side; this means Zn is being oxidized and is therefore acting as the reducing agent.

A solution that can't dissolve any more solute at a given temperature is said to be

saturated

When the particles in a suspension and in a solution are compared, one difference is that particles in a suspension _________________

settle out of solution

Identify the type of reaction for this equation: Cl2(g) + 2KBr(aq) → 2KCl(aq) + Br2(l)

single-displacement

Bases feel

slippery or soapy

All of the following are homogeneous mixtures except which of the following? soil a salt water solution pure water a sugar water solution

soil

What type of solute-solvent combination is an alloy?

solid-solid

The substance dissolved in a homogeneous mixture is the .

solute

What type of chemical reaction is represented by the following word equation? iron + oxygen → iron(II) oxide

synthesis

To study the relationship between the pressure and volume of a fixed amount of gas, the ______________ must be held constant.

temperature

Reaction stoichiometry is based on chemical equations and ___________

the law of conservation of mass

When the entropy change of a system is positive,

the system becomes more random

Entropy increases as

the temperature of the system decreases.

If a chemist calculates the maximum amount of product that could be obtained in a chemical reaction, he or she is calculating the

theoretical yield.

Which of the following compounds would be most effective in lowering the melting point of ice on roads?

Na3PO4

Which of the following is not likely to precipitate out of solution in a double replacement reaction? CaCO3 All of these will precipitate out of solution CaSO4 NaCl

NaCl

What is the empirical formula for a compound that contains 27.14 g Na, 16.52 g N, and 56.48 g O?

NaNO3

Which of the following is a strong base? NaOH NH3 acetate ion aniline

NaOH

What element is required to be present for a combustion reaction to proceed?

Oxygen (gas)

Why do you write O2 when you see oxygen as part of an equation, rather than O or O3?

Oxygen must be written as O2 - it is a diatomic molecule O3 is ozone or You write oxygen as O2 in an equation because it takes two O to make an oxygen atom which is needed to make the formula happen. It also exsits as O2

To answer the following questions, use this equation which represents a reaction used commercially to produce elemental arsenic by heating arsenic(III) oxide with carbon. Show or describe your work in the space provided. 2As2O3 + 3C → 3CO2 + 4As a.If 4.0 mol of each reactant are available for the above reaction, the mixture remaining after the reaction should contain how many moles of Arsenic ? b. If 4.5 mol of each reactant are available for the above reaction, the mixture remaining after the reaction should contain how many moles of carbon dioxide?

Part A: We start with 4.0 mol of As2O3 and determine how many moles of As can be formed from that, so we multiply by the mole ratio: 4.0mol As2O3 x 4mol As/2mol As2O3 and we get 4mol As. Then, we take 4.0 mol of C, the other reactant, and multiply by the mole ratio with As: 4.0mol C x 4mol As / 3 mol C and we get 5.33 mol As. We choose the smaller answer, which is 4mol As. Part B: We do a very similar process to Part A, but this time, starting with 4.5 moles of each reactant and determining how much CO2 can be created. 4.5mol As2O3 x 3mol CO2/2mol As2O3 and we get 6.75 mol of CO2 4.5mol C x 3mol CO2 / 3 mol C and we get 4.5 mol CO2. We choose the smaller answer which is 4.5mol CO2.

Write the formula and give the name of the compound formed by the following ions in the space provided. Pb2+ and CrO4-

Pb(CrO4)2 lead (II) chromate If we criss-cross Pb+2 and CrO4-2, we get Pb(CrO4)2

In the expression 3CO2, the numbers 3 and 2 are, respectively,

a coefficient and a subscript.

The following formula can be described as which of these? C6H12O6

a molecular formula only.

In a chemical equation, what could be one interpretation if the formula of a substance is followed by the symbol (s)? a precipitate has formed Many molecules have been produced The substance is in the s phase The substance is plural

a precipitate has formed

How would you classify HCl, in the equation? HCl + H2O --> H3O + Cl-

a strong acid,

Which of the following equations represents a synthesis or combination reaction? a. 2Sb(s) + 3I2(g) --> 2SbI3(s) b. 2HgO(s) --> 2Hg(l) + O2(g) c. FeS(s) + 2HCl(aq) --> H2S(g) + FeCl2(aq) d. Zn(s) + H2SO4(aq) --> ZnSO4(aq) + H2(g)

a. 2Sb(s) + 3I2(g) --> 2SbI3(s)

Write the formulas for the following compounds in the space provided. Be sure to use the three line format to include the ions present, when necessary a. Carbon tetriodide b. Hydrogen gas

a. CI4 b. H2

Complete the following equations. Balance them in the space provided. If the reaction is re-dox, identify the entities that are oxidized and reduced in each of the re-dox reactions." a. Zn(s) + HCl(aq) → b. Mg(s) + steam

a. Zn + 2HCl --> ZnCl2 + H2 Zinc is oxidized and hydrogen is reduced b. Mg + H2O --> MgO + H2 magnesium is oxidized and hydrogen is reduced

Balance the following equations in the space provided. If the reaction is re-dox, identify the entities that are oxidized and reduced in each of the re-dox reactions. If the reaction is a precipitation reaction, identify the precipitate in each of the precipitate reactions. a. . Zn(OH)2 + CH3COOH → Zn(CH3COO)2 + H2O b. PbO2 --> PbO + O2

a. Zn(OH)2 + 2CH3COOH → Zn(CH3COO)2 + H2O b. 2PbO2 --> 2PbO + O2 Pb on the left is reduced oxygen on the left is oxidized

Identify each chemical equation as a synthesis, decomposition, single-displacement, or double-displacement reaction. a. MgO(s) + H2O(l) → Mg(OH)2(s) b. H2 + O2 --> H2O

a. synthesis b. synthesis Part A and B both represent a synthesis reaction since we are taking 2 things and combining them to make 1 thing.

Determine the rate law equation for the following reaction, given the experimental data shown below. 3A→B

Your Answer: R=k[A]2

Write a word equation for 2NaI + Cl2 → 2NaCl + I2

Your Answer: Sodium Iodide + Chlorine = sodium chloride + iodine

What is the oxidation number of Mn in MnO4-? +4 +7 +5 +6 +8

+7 The Oxygens are each -2 and since there are 4 of them, that gives us a total of -8. If the ion is overall -1 charged, that means the Mn must be +7 so that +7 and -8 leaves us with -1.

The formation of a solid product in a chemical reaction is represented by the symbol

(s)

For the reaction represented by the equation H2(g) + \frac{1}{2} 1 2 O2(g) \longrightarrow ⟶ H2O(g), Use the data in the following table to calculate the \Delta Δ H Standard Enthalpies and Entropies Substance Standard enthalpy of formation (kJ/mol) Standard entropy (J/mol) H2(g) 0 130.7 O2(g) 0 205.1 H2O(g) 242 188.7 CO2(g) 393 213.8 C(s) (graphite) 0 5.7

-242 kJ Q # 21: The equation here for enthalpy of the reaction is enthalpy of products - enthalpy of reactants. Our product is H2O which has an enthalpy value of 242 kJ/mol and reactants are H2 and O2 which both have enthalpy values of 0. So we have 242 - 0 which gives us 242 kJ/mol.

Use the following chemical equation to answer the question. Mg(s) + 2H3O+(aq) +Cl-(aq)→Mg2+(aq) + 2Cl-(aq) + H2(g) + H2O(l) If 0.060 g of magnesium completely react in 25 s, what is the average reaction rate in moles/second over that time interval? (The atomic mass of Mg is 24.3 amu.) Show and describe your work

.060 g mg x (1mol/24.3 g Mg) = 2.469 x 10-3 mol mg average rate = delta(mol mg) / delta T = 9.9 x 10-5 mol / s Start with 0.060g Mg and convert to moles by multiplying by 1mol Mg /24.3 g Mg which gives us 0.002469moles and then we want to find the average reaction rate in "moles/second" so we would divide the 0.002469moles by 25 seconds to get the correct answer.

What is the molarity of a solution composed of 8.210 g of potassium chromate, K2CrO4 (molar mass = 194.20 g/mol), dissolved in enough water to make 0.500 L of solution?

.0846 M

How many grams of MgCl2 (molar mass = 95.20 g/mol) will be formed from 25.6 mL of a 0.100 M HCl solution reacting with excess magnesium metal? (The other product is hydrogen gas). You will need a balanced equation to solve this problem. Show or describe all of the calculations used to solve this problem, including conversion factors.

.1218 grams I think but the equation could differ but I think the one half should be added due to the balanced form of the equation 0.122 g

What is the mass of a sample that absorbs 32 J of energy when it is heated from 214 K to 284 K and has a specific heat of 0.20 J/(gK)?

2.3 g

Convert 725 mm Hg to atm. Be sure to show or describe your calculations including conversion factors in the space provided.

.953 ATM 760 mm HG = 1 atm so 725 divded by 760 = .953

A glass column is filled with mercury and inverted in a pool of mercury. The mercury column stabilizes at a height of 729 mm above the pool of mercury. What is the pressure of the atmosphere?

.959 726/760mmhg

A gas sample is heated from -20.0°C to 57.0°C and the volume is increased from 2.00 L to 4.50 L. If the initial pressure is 0.140 atm, what is the final pressure?

0.0811 atm

What will be the molarity of a solution if 25.0 mL of water is added to 125 mL of a 0.15 M NaOH solution ?

0.125 M

What is the molarity of a 1.68 L solution containing 25.00 g KCl?

0.200 M

What is the molarity of an NaOH solution if 4.37 mL is titrated by 11.1 mL of 0.0904 M HNO3?

0.230 M

What is the molarity of a solution of H2SO4 if 49.0 mL of it are neutralized by 68.4 mL of 0.333 M NaOH solution? Show or describe all work for full credit.

0.232 M

What is the volume of 2.0 g of CS2 vapor (molar mass = 76.15 g/mol) at 70.°C and 726 mm Hg? Show or describe all of the work required to solve this problem including any conversion factors (with units) in the space provided. (R = .0821 L\cdot ⋅ atm / mol\cdot ⋅ Kelvin).

0.77 L I was a bit confused on your work where you got the 96.558 attached to the V from? To find P, we should take 726mm Hg and divide by 760 mm Hg to get to atm which would be 0.955atm. On the right side where we have nRT, we should have 0.026 moles (0.0821) (343K) and I am seeing 8.314 next to the 0.026 moles? Since you had some of the work correct, I gave you partial credit.

What is one correct interpretation of the chemical equation : P4O10 + 6H2O ⟶ 4H3PO4

1 mol of P4O10 + 6 mol of H2O reacts to form 4 mol of H3PO4

What would be the conversion factor for deriving the number of moles of salicylic acid, C7H6O3, from a given number of grams of salicylic acid ?

1 mole C7H6O3 / /137 grams C7H6O3

Calculate the [H3O+] and [OH-] for the solution and show or describe all work for full credit: 1 x 10-4 M NaOH

1 x 10 -10 hydronium 1 x 10 -4 hydroxide

What is the hydronium ion concentration of an aqueous solution that has a pH of 5.0? Show or describe all work for full credit.

1 x 10-5

Write the formula for each of the following acids in the space provided: hydrosulfuric acid Phosphoric acid Nitric acid

1) H2S 2) H3PO4 3) HNO3

Write the name of each of the following acids in the space provided. HClO H3PO4 HCl

1) Hyphochlorus 2) Phosphoric acid aka the classic 3) Hydcrochloric also a classic acid

Calculate the [H+] in a solution that has a pH of 9.88.

1.3 x 10-10 M

How many moles of Li2S can be obtained from the following chemical equation if there are 3 moles of each reactant available? Na2S + 2LiNO3 ⟶ 2NaNO3 + Li2S

1.5 We start with 3 mol of Na2S and multiply by the mole ratio with Li2S so times 1mol Li2S / 1 mol Na2S which gives us 3 mol Li2S. Then, we start with 3 mol of the other reactant LiNO3 and multiply by the mole ratio with Li2S so times 1mol Li2S / 2 mol LiNO3 which gives us 1.5 mol Li2S. Since 1.5 mol Li2S is the smaller answer, that is the one we choose.

One mole of NaCl was found in a 345g sample of lakewater. How salty is this water in parts per million? The molar mass of NaCl = 58.44g/mol

1.7 x 105 ppm We take the 1 mol NaCl and change it to grams by multiplying 1mol NaCl x 58.44g / 1mol which gives us 58.44g NaCl. We take 58.44g NaCl / 345g lakewater x 10^6 to get 169391ppm, or 1.7x10^5 ppm

Calculate the pH of solution with a [OH-] of 1.0 x 10-4

10 In Q # 10, we are given the [OH-] but are asked to find the pH - there is no 1 step way to correlate these 2 values. We must first find the pOH by taking -log (1.0x10^-4) which is a pOH of 4. Then, we take 14-4 to get the pH of 10.

A physics experiment is conducted at a pressure of 14.4 kPa What is this pressure in mm Hg? Reminder: 1.00 atm = 101,325 Pa = 101.325 kPa =14.69 psi

108 mmHg

Exactly 15.0 g of a substance can be dissolved in 150.0 g of water. What is the solubility of the substance in grams per 100 g of water? Show or describe all of the calculations used to solve this problem, including conversion factors.

10g / 100g water You want to express the solubility in terms of grams dissolved per 100 g of water (instead of 10%).. but, if we have 10% solubility, then in 100 g of water, we know only 10 g should dissolve.

Which of the following would represent the greatest pressure? Show or describe all of the work required to solve this problem. Reminder: 1.00 atm = 101,325 Pa = 101.325 kPa =14.69 psi = 760 mm Hg A. 0.680 atm B. 517 mm Hg C. 11.4 psi D. 62106Pa E. 14.1 in Hg

11.4 psi

Consider a sample of gas in a container on a comfortable spring day. The Celsius temperature suddenly doubles, and you transfer the gas to a container with twice the volume of the first container. If the original pressure was 12 atm, what is a good estimate for the new pressure? Explain your answer.

12 Atm If the volume and temperature both double, these changes essentially cancel each other out, and the pressure would remain the same as it was before (12 atm).

For the reaction represented by the equation SO3 + H2O → H2SO4, what is the percentage yield if 250 g of sulfur trioxide reacts with excess water to produce 365 g of sulfuric acid? The molar masses of the elements are: Hydrogen, 1.01 g/mol Oxygen, 16.00 g/mol Sulfur, 32.07 g/mol

120%

A 10.2-L canister of oxygen gas contains 58.6 mol of gas at a temperature of 25.0°C. What is the pressure of the gas? (R = 0.0821 L atm / mol K)

141 atm

The volume of a gas at 7.00°C is 49.0 mL. If the volume increases to 74.0 mL and the pressure is constant, what will the temperature of the gas be? Show or describe all of the work required to solve this problem including any conversion factors (with units) in the space provided.

150 degrees You have the correct equation (Charles Law) and you solved it for T2: T1V2/V1 but plugging in to that would give us 280K (74mL) / 49mL and I didn't see that in your work, so I am not sure where you got your answer from?

What is the total enthalpy of formation of the reactants if the enthalpy of reaction is -520 kJ/mol and if the total enthalpy of formation of the products is -670 kJ/mol (adjusted for the coefficients)?

150 kJ/mol Full credit requires the equation \Delta Δ H\circ ∘ = sum of ( \Delta Δ Hf of products) - sum of (\Delta Δ Hf of reactants) OR \Delta Δ H\circ ∘ = sum of [( \Delta Δ Hf of products) x (mol products)] - sum of [(\Delta Δ Hf of reactants) x (mol of reactants)] = 670-520 Question 14 0 / 1 pts The specific heat of a substance is dependent on the energy lost or gaine On # 13, we have the total enthalpy of the reaction at -520 and that equals products - reactants which would be -670 - x. To solve for x (enthalpy of reactants), we would take -520 + 670 which is +150 = -x, or x = -150.

What is the correct formula mass for tin (II) hydroxide, Sn(OH)2?

152.7 g

Write the answers to the questions below, and show your work in the space provided. Use the table below to answer the questions. Element Symbol Atomic mass (AMU) Bromine Br 79.90 Carbon C 12.01 Chlorine Cl 35.45 Hydrogen H 1.01 Iodine I 126.90 Iron Fe 55.85 Lead Pb 207.2 Nitrogen N 14.01 Oxygen O 16.00 Potassium K 39.10 Sodium Na 22.99 Sulfur S 32.07 If cyclohexanol is burned as a fuel according to the following equation, how many moles of oxygen are needed to produce 13.7 mol of carbon dioxide? 2C6H12O + 17O2 ⟶ 12CO2 + 12H2O

19.4 mol O2 Show work as to how the answer was found O2:CO2 17:12 Unknown- O2 (mol) Known- CO2(13.7mol) 17molO2/12molCO2 13.7CO2 x 17mol O2/12 mol CO2 =19.4 mol O2

What is the mole ratio of water to oxygen In the equation 6CO2 + 6H2O → C6H12O6 + 6O2,

1:1

What is the mole ratio of iron (III) oxide to iron in the chemical reaction described by the equation: 4Fe(s) + 3O2(g) ⟶ 2Fe2O3(s)

1:2 figure out why

You have two samples of the same gas in the same size container, with the same pressure. The gas in the first container has a Kelvin temperature four times that of the gas in the other container. What is the ratio of the number of moles of gas in the first container compared to that in the second ?

1:4

Which of the following expressions is not a legitimate conversion factor?

1g C / 6.022x10-23 atoms c

Which expression represents the concentration of H3O+ions in solution? 1x10-14 [OH-] [OH-] ÷ 10-14 1x10-14 - [OH-], 1x10-14 [OH-],

1x10-14 [OH-]

For a gas, which two variables are directly proportional to each other (if all other conditions remain constant)? I. T and n II. V and n III. V and T

2 and 3 only

Which set of coefficients will balance the equation below? LiOH + Ba(NO3)2 --> Ba(OH)2 + LiNO3 2, 1, 1, 2 1, 1, 1, 1 1, 2, 2, 1 2, 1, 2, 1

2,1,1,2

Which coefficients correctly balance the formula equation below? KClO3(s) → KCl(s) + O2(g)

2,2,3

A solution is made by dissolving 100. g of CoCl3 (cobalt(III)chloride) in 250. g of water. Calculate the molality of the solution

2.42 m

A balloon has a volume of 2.32 liters at 24.0°C. The balloon is heated to 48.0°C. Calculate the new volume of the balloon.

2.51 L

Solid calcium hydroxide is dissolved in water until the pH of the solution is 11.44. What is the hydroxide ion concentration [OH-] of the solution?

2.8 x 10-3 M In Q # 7, we are given the pH of 11.44. In order to find the [OH-] we are being asked for, we should find the pOH since [OH-] = 10^-pOH. We can do 14-11.44 to find the pOH of 2.56. Then we take 10^-2.56 to find the concentration of OH

When calcium carbonate is heated, it produces calcium oxide and carbon dioxide. The equation for the reaction is CaCO3(s) --> CaO(s) + CO2(g). How many grams of calcium carbonate (molar mass = 100.09 g/mol) must be decomposed to produce 5.00 L of carbon dioxide at STP? Show or describe all of the work required to solve this problem including any conversion factors (with units) in the space provided. (R = .0821 L\cdot ⋅ atm / mol\cdot ⋅ Kelvin).

22.3 g You had the right set-up for PV = nRT and we use that to find n, but there is an additional step needed in order to find the molar mass of the gas (grams/mole). Once we use PV=nRT, we should get 0.089 moles for n. To find the molar mass, we need to take the given 0.716g divided by the 0.089 moles to get 8g/mol.

For a reaction involving reactants or products in the gas phase at STP, the molar ratios can be used for stoichiometry if the volume of any gas is given. This is because it was determined that 1 mole of gas at STP is exactly

22.4 L

Mrs. Jones Environmental Science class collected water samples from a nearby river. They found that in a container containing 138 grams of water, 3.45 mg of Mercury could be detected. What is the parts per million (ppm) of the mercury in that water sample? Show or describe all of the calculations used to solve this problem, including conversion factors.

25 ppm

What mass of Al is expected from the reaction of 52.5 g of Al2O3? 2Al2O3(l) → 4Al(s) + 3O2(g) The molar masses are: Aluminum, 26.98 g/mol Oxygen, 16.00 g/mol

27.8 g Al

What is the balanced equation for the conversion of hydrogen peroxide to water?

2H2O2 → 2H2O + O2

What is the balanced equation for the conversion of hydrogen peroxide to water? 8H+ + 3O22-⟶ 4H2O + O2 H2O2⟶ H2O + O2 2H2O2 ⟶ 2H2O + O2 4H2O2⟶ 4H2O + O2

2H2O2 ⟶ 2H2O + O2

For the equation P4(s) + 5O2(g) → P4O10(s), if 3 mol of phosphorus react with 10 mol of oxygen, the theoretical yield of tetraphosphorusdecoxide will be

2mol

A useful pH range for an indicator in neutralizations involving strong acids and weak bases is

3.1 to 4.6.

How many moles of potassium chloride are produced from 119 g of chlorine gas when KBr is in excess in the following equation? Cl2 + 2KBr → 2KCl + Br2 The masses are: Chlorine, Cl, 35.45 amu, Bromine, Br, 79.90 amu, Potassium, K, 39.10 amu Show or describe your work in the space provided Your Answer:

3.36 mol On Q # 8: Start with 119g Cl2 x 1molCl2/70.9g Cl2 and then by the mole ratio of 2mol KCl/1mol Cl2.

Use the reaction E + F ⇔ 2G and the equilibrium concentrations 0.60 mol/L for E, 0.80 mol/L for F, and 1.30 mol/L for G to calculate the equilibrium constant. E, F, and G are all gases.

3.5 We start by writing a Keq for the reaction which would be: Keq = [G]^2 / [E]{F] and then we plug in the given values for [G], [E], and [F] and solve.

What is the percentage of iron in iron(III) chloride, FeCl3? The molar mass of FeCl3 is 162.2 g/mol.

34.43%

For the reaction represented by the equation N2 + 3H2 → 2NH3, how many moles of nitrogen are required to produce 8 mol of ammonia?

4

How many total moles of oxygen atoms are there in one mole of silver(I) phosphate, Ag3PO4?

4

If [H3O+] = 8.26 10-5M, what is the pH of the solution?

4.083

The gas in an aerosol container is at a pressure of 3.50 atm at 24.0°C. The caution on the container warns against storing it at temperatures above 95°C. What would the gas pressure in the container be at 95°C?

4.34 atm

What is the mass of 0.240 mol glucose, C6H12O6? The atomic masses are: Carbon, C, 12.01 amu, Hydrogen, H, 1.01 amu, Oxygen, O, 16.00 amu. Show or describe the work required to calculate the answers in the space provided

43.2G .240(6x12)+(12)+(6x16) = 43.2

In the equation 2Al2O3 → 4Al + 3O2, what is the mole ratio of aluminum to oxygen?

4:3

Which of the following equations represents the balanced equation for the reaction of iron and oxygen? Fe + 3O2 → 2Fe2O3 Fe + O2 → Fe2O2 Fe + O → FeO 4Fe + 3O2 → 2Fe2O3

4Fe + 302 --> 2Fe2O3

Which of the following equations represents the word equation? Solid iron is oxidized to produce iron (III) oxide. 2Fe + 3O ⟶ Fe2O3 4Fe + 3O2 ⟶ 2Fe2O3 3Fe + 3H2O ⟶ Fe3(OH2)3 3Fe + O2 ⟶ Fe2O3

4Fe + 3O2 ⟶ 2Fe2O3

How many moles of Sodium Nitrate can be obtained from the complete reaction of 2.5 moles of sodium sulfide in the following chemical equation? Na2S + Cd(NO3)2 ⟶ 2NaNO3 + CdS

5 We start with the given 2.5mol Na2S and multiply by the mole ratio so 2mol NaNO3 / 1mol N2S so we get 5mol NaNO3.

Zinc metal is added to hydrochloric acid to generate hydrogen gas, which is collected over a liquid whose vapor pressure is the same as pure water at 20.0°C (18 torr). The volume of the gas mixture is 1.7 L and its total pressure is 0.810 atm. Determine the partial pressure of the hydrogen gas in this mixture. (R = .0821 L\cdot ⋅ atm / mol\cdot ⋅ Kelvin).

598 torr

What mass of water must be used to make a 1.35 m solution that contains 8.20 mol NaOH? Show or describe all of the calculations used to solve this problem, including conversion factors.

6.07L or 6.07KG

What is the percent by mass of ethanol (C2H5OH) in a 1.5-m aqueous solution? Show or describe your work.

6.5 % We start with 1.5 molality which means 1.5 moles of ethanol per 1 kg of solvent. 1.5mol C2H5OH x 46.07g / 1mol C2H5OH to get 69g of ethanol. We plug this in to the mass % equation: (69g ethanol / 69g ethanol + 1000g water ) x 100

One mole of Lithium atoms has a mass of

6.94 g.

Calculate the pH of solution with a [H+] of 1.0 x 10-7

7

What is the actual yield if the theoretical yield for a chemical reaction is 100. g and the percentage yield is 70.0%? Show or describe the calculations required to solve the problem

70g

The specific heat of silver is 0.234 J/(g\cdot ⋅ K). Calculate the amount of energy that is needed to raise the temperature of 175 g of silver from 22.5°C to 40.0°C.

717J

What is the value of G at 182.0 K for a reaction in which H = +85 kJ/mol and S = -3.50 kJ/(mol\cdot ⋅ K)? Show or describe all of the calculations needed to solve this problem.

722 KJ / mol Good job on your Module 11 test - for Q # 11, you had all the work and equation set-up correctly, but just had a negative sign and the answer should have been positive - I gave you 2.5/3 pts.

The mass of a 2.0 L sample of a gas is 0.716 g at STP. What is the molar mass of the gas? Show or describe all of the work required to solve this problem including any conversion factors (with units) in the space provided.

8g / mol

What is the pH of a 10-5 M KOH solution?

9

A 5.12 molal solution of NaCl is prepared. How many grams of NaCl are present in a sample containing 3.24 kg of water?

969 g We set up the molality equation which is m = moles of solute / kg of solvent. 5.12 m = x / 3.24 kg Cross-multiply to get 16.59 moles NaCl. To find the grams of NaCl, we take 16.59mol x 58.44g / 1 mol to get 969g.

synthesis reaction/Combination Reaction

A + B --> AB

Single Replacement

A + BC --> B + AC

Explain the role of a catalyst in terms of activation energy.

A catalyst lowers the activation energy by changing the reaction pathway

single-displacement reaction

A+BC->AC+B

double replacement reaction

AB + CD --> AD + CB

decomposition reaction

AB --> A + B

Which of these explains why the grass might be covered in dew on a morning? The air was cooled as heat energy was released Heat energy was transferred from the air All of these are contributing factors to the collection of dew on the grass The gaseous water within the air was converted to liquid because the temperature decreased

ALl are correct

Which of the following can act as a Lewis acid? Cl (aq) NH3(aq) BF(aq) Ag+(aq)

Ag+(aq)

In order to calculate the enthalpy change for a reactions, one must Know the individual steps involved in the reaction Be given the enthalpy values for each step of the reaction Add the enthalpy values for each step of the reaction All of these are needed according to Hess's Law

All of these are needed according to Hess's Law

Which of the following is true regarding double-displacement reactions? All of these are true about double displacement reactions Two products are formed. A precipitate may form. The ions of the two reactants must be exchanged.

All of these are true about double displacement reactions

The ideal gas law combines Boyle's law, Charles's law, Gay-Lussac's law, and .

Avagadro's Law

Equal volumes of gases at the same temperature and pressure contain equal numbers of molecules.

Avogadro's Law

Identify the following as true of acidic or basic solutions at 25C. OH-1 = 1 x 10 -4

Basic

If calcium is listed above magnesium in the activity series, and magnesium is listed above zinc, which of the following reactions is possible? a. Ca(s) + MgCl2(aq) ⟶ b. Zn(s) + MgCl2(aq) ⟶ c. Zn(s) + CaCl2(aq) ⟶ d. Mg(s) + CaCl2(aq)

Both b and d

The volume of a fixed mass of gas varies inversely with the pressure at constant temperature.

Boyles Law

Whose theory of acids and bases do conjugate acids and bases belong to?

Brønsted-Lowry

The volume of a fixed mass of gas varies directly with the kelvin temperature at constant pressure.

Charles Law

The empirical formula for a compound is C2H5 and its formula mass is 58 amu. What is its molecular formula? The atomic masses are: Carbon, C, 12 amu, Hydrogen, H, 1.01 amu. Show or describe your calculations in the space provided

C4H10

combustion reaction

CH + O2 --> H2O (Oxygen is needed)

Which of the following is not a strong acid?

CH3COOH

Write the balanced chemical equation for calcium hydroxide → calcium oxide + water

Ca(OH)2 --> CaO + H2O

The law that relates the temperature and volume of a gas to each other is known as

Charles's law.

The relationship between pressure, volume, and temperature is expressed by this law.

Combined Gas law

What two things are required for a collision to be effective?

Correct orientation and enough energy or enough energy, a favorable orientation a favorable orientation, enough energy

Which of the following equations represents a single-displacement reaction? a. FeS(s) + 2HCl(aq) --> H2S(g) + FeCl2(aq) b. 2HgO(s) --> 2Hg(l) + O2(g) c. 2Sb(s) + 3I2(g) --> 2SbI3(s) d. Zn(s) + H2SO4(aq) --> ZnSO4(aq) + H2(g)

D. Zn(s) + H2SO4(aq) --> ZnSO4(aq) + H2(g)

The total pressure of a mixture of gases is equal to the sum of the partial pressures of the component gases.

Dalton's Law

Consider the reaction represented by the equation 2NO(g) + O2(g) ⇔ 2NO2(g). If the volume of the reaction chamber is decreased, then the

Decreasing the volume of the reaction chamber would increase the pressure. Increasing the pressure would shift to the side with fewer moles of gas which is the right (forward).

For the reaction 2 A(g) + B(g) → C(g) + D(g) + energy,

DeltaS is negative and Delta H is negative.

How would you determine the empirical formula for benzene, C6H6? Correct!

Divide the subscripts by the smallest common divider

The reaction Pb(NO3)2(aq) + 2KI(aq) --> PbI2(s) + 2KNO3(aq) is classified as which type of reaction? syntheses combustion double-displacement decompoition single-displacement

Double displacement

You have just opened a new box of cereal. When you try to open the bag, you notice that the bag looks sort of collapsed. Which of these is responsible for the bag looking collapsed?

Effusion

What is the name for the following? H+

Either a proton or a hydrogen ion

Explain why the activation energy is important in endothermic chemical reactions.

Energy is needed to create the activated complex for the reaction to move forward

Explain how entropy change influences the tendency for a reaction to occur. Be very specific and detailed in your answer.

Entropy is a measure of the degree of randomness of the particles in a system. In nature, processes tend to proceed in the direction that increases the randomness of a system. Therefore, a reaction in which entropy increases is more likely to occur than one in which entropy decreases.

Consider three 1-L flasks at STP. Flask A contains NH3 gas, flask B contains NO2 gas, and flask C contains N2 gas. In which flask do the molecules have the highest average velocity?

Flask A

Which of the following may be visible even though a chemical reaction has not occurred? energy is released as heat energy is released as heat and a precipitate has formed a precipitate has formed gas bubbles are released

Gas bubbles are released

The rates of effusion of gases at the same temperature and pressure are inversely proportional to their molar masses.

Graham's Law

At constant temperature and pressure, the volumes of gaseous reactants and products can be expressed as ratios of small whole numbers.

Guy Lussac's law of combining volumes

The pressure of a fixed mass of gas varies directly with the kelvin temperature at constant volume

Guy-Lussac Law

Which equation is not balanced? H2 + 2O2 → 2H2O 2Cs + Br2 → 2CsBr 2AlN → 2Al + N2 2H2 + O2 → 2H2O

H2 + 2O2 → 2H2O

The substances produced when NaOH(aq) neutralizes HI aq) are

H2O and NaI

List the conjugate acid-base pairs for the following equation: H2O(l) + NH3(g) ⇔ NH4+ (aq) + OH-1 (aq)

H2O and OH NH3 and NH4+

In which of the following reactions does the H2PO4- ion act as an acid?

H2PO4- + H2O ⟶ H3O+ + HPO4-2

Which of the following is a diprotic acid?

H2SO4 or sulfuric acid

What is a conjugate acid-base pair In the reaction represented by the equation HF + H2O --> <-- F- + H3O+

H3O+ and H2O.

An example of a good buffer solution is one that contains

HNO2 and NaNO2.

Which of the following is amphoteric? Hpo4 -2 PO4-3 H+, H3PO4,

Hpo4-2

Pressure times volume equals molar amount times 0.0821 L atm/(mol K) times temperature in kelvins.

Ideal Gas law

How do the enthalpy of products and reactants differ in endothermic and exothermic reactions?

In an endothermic reaction, energy is absorbed as heat, and the enthalpy of the reactants is lower than the enthalpy of the products. Therefore, the enthalpy change is positive. In an exothermic reaction, energy is released as heat, and the enthalpy of the products is less than the enthalpy of the reactants. Therefore, the enthalpy change is negative.

To conduct electricity, a solution must contain which of the following?

Ions

When the volume of solvent increases, what happens to the mass of solute that can dissolve in a saturated solution at a given temperature?

It increases

In a chemical equation, the upward arrow used instead of a letter after a product will indicate what about the product?

It is a gas

Which of the following is not true regarding a properly written chemical equation? It must contain proper chemical formulas It should represent known data It must be balanced It must show the formation of a precipitate or a gas

It must show the formation of a precipitate or a gas

Give the equilibrium expression for the reaction CaF2(s) \Longleftrightarrow ⟺ Ca+2(aq) + 2(aq)

K = [Ca+2][F-]2 The Keq expression is equal to the [products] / [reactants] but we leave out solids and pure liquids. For this reaction, the Keq would just be: [Ca+2][F-1].

In the space provided, write a word equation for the chemical reaction indicated below: 2LiI + Cl2⟶ 2LiCl + I2

Lithium and chlorine combine to produce lithium chloride and iodine

What is the percent by mass of Nitrogen in Nitrogen dioxide, NO2? The masses for the elements are: Nitrogen, N, 14.01 amu, Oxygen, O, 16.00 amu. Show or describe your work in the space provided.

N = 30.44% 14.01 32.00 ------- 46.01

What is the molecular formula for the compound with an empirical formula of NO2 and a formula mass of 92.02 amu?

N2O4

In the reaction represented by the equation the conjugate acid of NH3 is

NH+4

In the following reaction, which substance acts as a Brønsted-Lowry base? HCl + NH3 ⟶ NH4+ + Cl-

NH3

Which of the following is a conjugate acid/base pair?

NH4+/NH3 In Q # 3, to identify a conjugate acid/base pair, we want to see which pair has one H+ missing. For example, if we remove 1H+1 from NH4+, we would get NH3. However, if we remove 1H+1 from H2SO4, it would be HSO4-1, not SO4-2 (that is missing 2 hydrogens instead of just 1).

Which of these gases effuses the slowest under the same conditions?

NO2

What is the half-reaction of Na in the reaction 4 Na(s) + O2⟶ 2 Na2O Na(s)⟶ Na+1 Na(s) ⟶ Na+ + 1e- Na(s) ⟶ Na+2 + 2e- Na(s)⟶ Na+2 + 1e-

Na(s)⟶ Na+1

Which equation below violates the law of conservation of mass? 2Fe2O3 + 3C → 4Fe + 3CO2 2KCl + Br2 → 2KBr + Cl2 Na2CO3 + 2HCl → 2NaCl + CO2 2H2 + O2 → 2H2O

Na2CO3 + 2HCl → 2NaCl + CO2

For the reaction represented by the equation 2Fe+ O2 → 2FeO, how many moles of iron oxide will be produced from 8.00 mol of iron when O2 is in excess? The molar masses are : Iron, Fe, 55.85 amu, Oxygen, O, 16.00 amu

Show or describe your work in the space provided. Your Answer: 8 mol FeO

In the formation of silicon carbide represented by the chemical equation SiO2(s) + 3C(s) → SiC(s) + 2CO(g), 8 mol of each reactant are available for the reaction. What substance is the excess reactant?

SiO2

You mix solution A with solution B in a beaker. Which of the following observations does not help you prove that a chemical reaction has occurred?

Solution A, solution B, and the mixture are all yellow.

Compare the properties of solutions, suspensions, and colloids. Be specific and give examples.

Solutions= sugar and water, when you mix them together the sugar disappears and the drink looks the same suspensions= mud and water the mud collects at the bottom becuase the particles are to large so they settle at the bottom. colloids= milk the particles are self-suspended so the solution seems constantly mixed and together small enough to be suspended constantly

What type of chemical reaction generally results in the formation of a single product? double-displacement single-displacement decomposition synthesis combustion

Synthesis

Describe in detail one factor that affects the solubility of a solution. Give an example that illustrates this. Be very specific

Temperature affect solubility of a solution for example if you are making tea you would want hot water to dissolve the sugar not cold water

How does temperature differ from heat? Get specific. Use terms and information from the unit.

Temperature is a measure of the average kinetic energy of a substance. Heat is the total thermal energy of the substance.

Which of the following is true about the Brönsted -Lowry definition of acids and bases?

The Brönsted -Lowry acids and bases also have conjugate acids and bases.

How does the energy of the activated complex compare with the energies of reactants and products?

The energy of the activated complex is greater than the energy of the reactants and products.

What does the small whole number that appears in front of a formula in a chemical equation represent?

The number of moles The ratio of chemicals

Which of the following indicates that a chemical equation is balanced?

The numbers of atoms of each element are the same on both sides of the equation.

Which graph represents Charles's Law?

The one with a strait line that shows a largest increase

How many grams of hydrogen are produced if 120 g of Na and 80.0 g of H2O are available for the reaction represented by the equation 2Na + 2H2O → 2NaOH + H2 The molar masses are: Sodium, Na, 22.99 amu, Hydrogen, H, 1.01 amu, Oxygen, O, 16.00 amu. Show or describe all of the calculations required in the space provided.

Your Answer: 4.5g 4.48 g H2 gas

What does the symbol delta or a triangle above the arrow in a chemical equation mean?

The reactions are heated

You have an unknown metal, X. You conduct two experiments. The results are shown in the table below. Procedure Result X(s) + NaCl(aq) no reaction X(s) + ZnCl2(aq) reaction of metal Which of the following statements is a logical conclusion based on the experimental data?

The unknown metal is higher on the activity series than zinc, but below sodium.

What does Boyle's law state?

The volume of a fixed amount of gas is inversely proportional to its pressure at constant temperature.

Explain the meaning of the phrase "like dissolves like" in terms of polar and non-polar substances. Be sure to include examples in your explanations.

The way that i understand this phrase is when oil and water are put together. I believe water is polar but oil is nonpolar so they will not combine or dissolve one another. same goes with sugar and water but they are both polar.

According to the equation C3H8 + 5O2 → 3CO2 + 4H2O, when O2 is in excess, how many grams of carbon dioxide are produced from the combustion of 250 g of ethane, C3H8? Use the table below and show or describe your work in the space provided Element Symbol Atomic mass (AMU) Carbon C 12.01 Chlorine Cl 35.45 Hydrogen H 1.01 Iodine I 126.90 Iron Fe 55.85 Lead Pb 207.2 Nitrogen N 14.01 Oxygen O 16.00

Your Answer: 748.299(g) of CO2

Write the general equation for a decomposition reaction.

Your Answer: ABC --> A + BC

Distillation is an important method for separating mixtures based which of the following?

Volatility

Which of the following is a product that can be formed by double displacement reactions? water nitrogen gas precipitation oxygen gas

Water

Write the answers to the questions below, and show your work in the space provided. Use the table below to answer the questions. Element Symbol Atomic mass (AMU) Bromine Br 79.90 Carbon C 12.01 Chlorine Cl 35.45 Hydrogen H 1.01 Iodine I 126.90 Iron Fe 55.85 Lead Pb 207.2 Nitrogen N 14.01 Oxygen O 16.00 Potassium K 39.10 Sodium Na 22.99 Sulfur S 32.07 According to the equation C3H8 + 5O2⟶ 3CO2 + 4H2O, When O2 is in excess, how many grams of carbon dioxide are produced from the combustion of 250. g of ethane, C3H8

We start with 250g C3H8 and times by the molar mass of C3H8 so 1mol C3H8/44.1g KI and then times the mole ratio with carbon dioxide so 3mol CO2 / 1mol C3H8 and then multiply by the molar mass of CO2 so 44.01 g CO2/1mol CO2 to get 748g CO2.

Describe an energy profile for an endothermic reaction. Be sure to completely describe the reactants, products, activated complex, and activation energy and where you would find each if you made a diagram and what they might look like.

Well I would draw a R with an upward slop a slight dip then a P at the end at the top of the bump I would label activation complex and the space below the bump towards the R I would label activation energy refer to page 507

In the space provided, write a balanced chemical equation for each word equation indicated below: Magnesium hydroxide produces Magnesium oxide + water

Your Answer: Mg(HO)2 --> MgO + H2O

Identify each chemical equation as a synthesis, decomposition, single-displacement, or double-displacement reaction. a. 2H2O(l) ⟶ 2H2(g) + O2(g) b. Cl2(g) + 2KBr(aq) ⟶ 2KCl(aq) + Br2(l)

Your Answer: a. Decomposition b. single displacement

Complete the following formula equations in the space provided. If the reaction is re-dox, identify the entities that are oxidized and reduced in each of the re-dox reactions. If the reaction is a precipitation reaction, identify the precipitate in each of the precipitate reactions. a. Mg(s) + steam ⟶ b. Cl2(g) + MgBr2(aq) ⟶

Your Answer: a. Mg + H2O --> MgO + H2 Mg is oxidized and hydrogen is reduced b. Cl2 + MgBr2 --> Br2 + MgCl2 Cl is reduced and Br is oxidized In Part B, the Cl is being reduced since it's going from 0 on the left to -1 on the right, and then the Br is being oxidized as it is going from -1 on the left to 0 on the right. All else was correct!

What are three observations that indicate a chemical change may be taking place?

Your Answer: change in odor color temperature

Which law must be satisfied for a chemical equation to be balanced.

Your Answer: conservation of mass law

The substance that is not completely used up in a chemical reaction is known as the

Your Answer: excess reactant

What is the effect on concentration if more CO(g) is added to the following equilibrium system? 2CO(g) + O2(g) → 2CO2(g)

[CO2] increases and [O2] decreases.

Which of the following indicates the most basic solution? pOH = 6.7 pH = 4.2 [H+] = 1 x 10-10 M At least two of the solutions are equally basic. They are all acidic [OH-] = 7 x 10-5 M

[H+] = 1 x 10-10 M

Write the Keq expression for the formation of ammonia, NH3, from its elements, as represented by the equation 3H2 + N2 \Longleftrightarrow ⟺ 2NH3 + 92 kJ?

[NH3]2/[H2]3 [N2] The Keq expression is equal to the [products] / [reactants] but we leave out solids and pure liquids. For this reaction, the Keq would be: K = [NH3] /[H2]^3 / [N2], no heat (KJ) would be included.

Which of the following equations represents a decomposition reaction? a. 2Sb(s) + 3I2(g) --> 2SbI3(s) b. 2HgO(s) --> 2Hg(l) + O2(g) c. FeS(s) + 2HCl(aq) --> H2S(g) + FeCl2(aq) d. Zn(s) + H2SO4(aq) --> ZnSO4(aq) + H2(g)

b. 2HgO(s) --> 2Hg(l) + O2(g)

In an acid-base titration,

base is added to acid or acid is added to base

In a single-displacement reaction, an element in the activity series most likely can replace any element

below it on the list.

Which equation below is a single replacement reaction? a. 2H2 + O2 ⟶ 2H2O b. 2KBr + Cl2⟶ 2KCl + Br2 c. 2Fe2O3 + 3C ⟶ 4Fe + 3CO2 d. Na2CO3 + 2HCl ⟶ 2NaCl + H2O + CO2

both b and c

The most steps are required to solve stoichiometry problems when the reactant is given in grams and the product is sought in You Answered

both grams and number of atoms require the same amount of steps

Which of the following is a reactant in the reaction described by the word equation below? iron + copper(II) sulfate --> iron(II) sulfate + copper

both iron and coppper

In a stoichiometric calculation to determine the mass of one substance that will react with a given amount, in moles, of a second substance, you need to know which of the following?

both the mole ratio of the unknown substance to the given substance and the molar mass of the unknown substance

What must be the same on each side of a chemical equation according to the law of conservation of mass? the mass of each element both the number of atoms of each element and the mass of each element the number of atoms of each element the number of molecules

both the number of atoms of each element and the mass of each element

Gay-Lussac recognized that at constant temperature and pressure, the volumes of gaseous reactants and products

can be expressed as ratios of small whole numbers.

Aqueous solutions of acids

carry electricity and have a sour taste

Name three ways that chemical equilibrium can be disturbed.

changes in concentration, changes in pressure, changes in temperature

The ratios of the volumes of the gaseous reactants and products in a chemical reaction at constant temperature and pressure can be determined from the

coefficients in the balanced equation.

Explain why someone might put salt in the water when boiling spaghetti noodles. Be as detailed as possible.

colligative properties and elevated boiling point must be mentioned for full credit or you add salt to the water pot because it increases the boiling point so the pasta would cook faster this is because the heat has to "work extra" to boil the water this is due to the number of new particles in the solution

A mixture of ethane and oxygen react to form carbon dioxide and water vapor. What type of chemical reaction is this?

combustion

The reaction 2C2H2(g) + 5O2(g) --> 4CO2(g) + 2H2O(l) is classified as which type of reaction? decomposition synthesis combustion double-diplacement both single replacement and synthesis

combustion (has oxygen)

Which of the following is not a colligative property conducting electricity lowering vapor pressure boiling-point elevation freezing-point depression

conducting electricity

A species that remains when an acid has lost a proton is a

conjugate base

According to Avogadro's law, 1 L of H2(g) and 1 L of O2(g) at the same temperature and pressure

contain the same number of moles

In stoichiometry, molar mass is used for which of the following?

convert the amount in moles of one substance to the mass of the substance.

Use the table of atomic masses to answer the following questions. Write your answer below, and show your work in the space provided. Element Symbol Atomic mass Element Symbol Atomic mass Aluminum Al 26.98 amu Lead Pb 207.2 amu Bromine Br 79.90 amu Lithium Li 6.94 amu Carbon C 12.01 amu Magnesium Mg 24.30 amu Chlorine Cl 35.45 amu Manganese Mn 54.94 amu Chromium Cr 52.00 amu Nitrogen N 14.01 amu Copper Cu 63.55 amu Oxygen O 16.00 amu Fluorine F 19.00 amu Sodium Na 22.99 amu Hydrogen H 1.01 amu Sulfur S 32.07 amu a. What is the molar mass of copper(II) chloride, CuCl2? b. What is the mass of 24.00 mol Magnesium hydroxide, Mg(OH)2?

copper (II) chloride = 134.45g/mol 24 mol Mg(OH)2 = 1400 g Be sure to follow the directions and show all work for full credit, especially on all of the math problems in this Module! Part A is correct. In Part B, we take 24.00mol Mg(OH)2 and multiply it by the molar mass of Mg(OH)2 which is 58.32g over 1 mol Mg(OH)2 to get 1400 g Mg(OH)2.

During reduction, one or more electrons are added to a substance, which does what to the substance?

decreases its oxidation number

Decreasing reactant concentration has what effect on the reaction.

decreases the reaction rate

Decreasing surface area has what effect on the reaction.

decreases the reaction rate

Pressure is

defined as the force per unit area

In a chemical equation, the symbol (aq) indicates that the substance is

dissolved in water.

In a reaction, the ions of two compounds exchange places in aqueous solution to form two new compounds. This reaction is called a

double-displacement reaction.

All redox reactions involve the transfer of

electrons

All redox reactions involve the transfer of ______________

electrons

Which of the following is not directly measurable?

enthalpy

The ____ is negative for exothermic reactions and positive for endothermic reactions.

enthalpy change delta H

At equilibrium, the rate of the forward reaction is_______ the rate of the reverse reaction.

equal to

Actual yield must be determined by

experiments

Which mixture exhibits the Tyndall effect?

fog

The presence of a catalyst may speed up a reaction by

forming a different activated complex with a lower activation energy

For any molecule, formula unit, or ion, the sum of the average atomic masses of all the atoms represented in a formula is the

formula mass.

If the temperature of an exothermic equilibrium system is decreased, the _________reaction will be favored.

forward In an exothermic reaction, the heat is located on the right (product) side since it is being given off. If we decrease the temperature, we want to shift to the same side that heat is on, which is the right (forward) direction.

What effect would decreasing the pressure have on this reaction? CaCO3(s) ⇔ CaO(s) + CO2(g)

forward reaction is favored

For the reaction represented by the equation N2 + 3H2 -->2NH3, a chemist must determine how many grams of nitrogen are needed to produce 500 g of ammonia. what is the given: ____________________ what is the unknown: ____________________

given balanced equation 500 g ammonia unknown - grams Nitrogen

A strip of pH paper

gives a quick approximation of pH

Which of the following solutions does not contain an electrolyte? glucose-water solution sodium chloride-water solution potassium bromide water solution all of these contain an electrolyte hydrochloric acid solution

glucose-water solution

The pH of a basic solution is

greater than 7

What is the solution process where water is the solvent?

hydration

An Arrhenius acid contains

hydrogen and ionizes in aqueous solution to form hydrogen ions.

As temperature increases, the solubility of solids in liquids generally ______________ .

increase

As pressure increases, the solubility of gases in liquids generally .

increases

The empirical formula will generally represent the actual composition of a(n) Correct Answer

ionic compond

Free energy is measured in units called __________________.

joules

Energy is measured in units of

joules and calories

Which of the following characteristics do gases generally have? low density no decrease in volume when pressure is increased closely packed particles no increase in volume when temperature is increased high density

low density

The specific heat of a substance is dependent on the energy lost or gained, temperature, and the _____________ of the substance.

mass Q # 14: If we think of the equation: Q = mc(deltaT), the specific heat, c, depends on the energy, temperature, and mass.

Which type of stoichiometry problem involves the most steps?

mass to mass conversions

Most manometers and barometers contain mercury. alcohol. oil. water.

mercury

Complete the following solution plan for the conversion factor: mol of given substance x mol of unknown/mol given =

mol of unknown

What is the unit for the conversion factor in the expression mass x (1 mol/ molar mass) g. mol/g. mol. g/mol.

mol/g

Which of the following concentration measures will change in value as the temperature of a solution increases?

molarity

What does a balanced chemical equation explicitly provides you with ?

mole ratios needed to solve a stoichiometry problem

Which mixture can be separated by filtration? mayonaise gelatin muddy water shaving cream

muddy water

List and describe at least three factors that can influence reaction rate.

nature of reactants, surface area, temperature, concentration, presence of catalysts or Surface) Spreading a piece of aluminum out will cause more reaction than just a ball of aluminum Temperature) Hotter the temperature the better it is such as when making tea Concentration) A dense amount of mercury will cause more reaction than a diluted amount Catalysts) By adding a catalyst a reaction will occur such as when a friend helped pull u up a ladder so you do not have to climb it

Choose the expression from the options which is most closely related to describe a spontaneous reaction positive G positive change in entropy positive H negative change in Gibbs free energy negative S negative change in enthalpy

negative change in Gibbs free energy

Identify pure water as acidic, basic, or neutral.

neutral

Which of the following is not a unit of pressure? atmospheres. pascals. newtons. torr.

newtons

If, in the reaction A + B → C + D, the quantity of B is insufficient to react with all of A excess product will form None of these are correct Both A and B limit the reaction B is the excess reagent the reaction rate will increase Neither A nor B limit the amount of product A is the limiting reactant

none of these are correct

How many protons per molecule can a monoprotic acid donate?

one

In the reaction represented by the equation 4Fe + 3O2 → 2Fe2O3, the O2 is the

oxidizing agent. The O2 is going from an oxidation number of 0 on the left to -2 on the right, so it is being reduced and is acting as the oxidizing agent.

The pressure exerted by each gas in a mixture is called the ________ ___________of that gas.

partial pressure

Which of the following factors does not affect the actual yield of a reaction?

particles no longer reacting with each other

The SI unit of pressure is pascals. torr. atmospheres. newtons.

pascals

Which acid is used to make fertilizers and detergents and is a flavoring agent in beverages?

phosphoric acid

Which of these best describes an endothermic reaction? positive Delta G positive change in entropy positive Delta H negative change in Gibbs free energy negative Delta S negative change in enthalpy

positive Delta H

Choose the expression from the options which best describes a reaction that increases disorder positive Delta G positive change in entropy positive Delta H negative change in Gibbs free energy negative Delta S negative change in enthalpy

positive change in entropy

The energy change, \Delta Δ E, for a reaction is the energy difference between which of these?

products and reactants

Which of the following does not increase the rate at which a solid dissolves in water?

using large pieces of the solid

A solution in which the pOH is 2.1 would be described as

very basic In Q # 5, if we have a pOH, it is always best to find the pH and then think back to the pH scale 1-14 with 1-6 being acidic and 8-14 being basic. To find pH from pOH, we take 14-pOH, so 14-2.1 is 11.9 pH. On the pH scale, 11.9 is very basic.

In the reaction described by the word equation sodium + water → sodium hydroxide + hydrogen gas

water is a reactant.

The conjugate of a strong base is a

weak acid