Chem Final Review

C2H4(g) + 3O2(g) → 2CO2(g) + 2H2O(g) For the reaction of ethelyene represented above, what is the value of deltaH if the combustion produced liquid water H2O(l), rather than water vapor H2O(g)? (deltaH for the phase change H2O(g)→H2O(l) is -44kJ/molrxn) A) -1279 kJ/mol B)-1323 kJ/mol C)-1367 kJ/mol D)-1411 kJ/mol

-1411 kJ/mol

The alkenes are compounds of carbon and hydrogen with the general formula CnH2n. If 3.50 gram of any alkene is burned in excess oxygen, what number of moles of H2O is formed? (A) 0.250 mole (B) 0.500 mole (C) 2.50 mole (D) 5.00 mole

.250 mole

A 1.0 L sample of aqueous solution contains 0.10 mol of NaCl and 0.10 mol of CaCl2. What is the minimum number of moles of AgNO3 that must be added to the solution in order to precipitate all of the Cl- as AgCl(s) ? (Assume that AgCl is insoluble) (A) 0.10 mol (B) 0.20 mol (C) 0.30 mol (D) 0.60 mol

.30 mol

What is the molarity of the Li+ ion in a solution prepared by dissolving 2.20 g of Li2SO4 (MM = 110.0 g/mol) in enough H2O to make 50.0 mL of solution? (A) 2.00 x 10-2 M (B) 4.00 x 10-2 M (C) 0.400 M (D) 0.800 M

.800 M

...BaH2(s) + ...H2O(l) → ...Ba+(aq) + ...OH-(aq) + ...H2(g) When the equation above is balanced and all coefficients reduced to their lowest whole-number terms, the coefficient for OH-(aq)is (A) 2 (B) 3 (C) 4 (D) 6

2

Magnesium is burned in excess air. When the equation for this reaction is correctly balanced and all coefficients are reduced to their lowest whole-number terms, the coefficient for the product is (A) 1 (B) 2 (C) 4 (D) 8

2

...Li3N(s) + ...H2O(l) → ...Li+(aq) + ...OH-(aq) + ...NH3(g) When the equation above is balanced and all coefficients reduced to their lowest whole-number terms, the coefficient for OH-(aq) is (A) 2 (B) 3 (C) 4 (D) 6

3

Of the following reactions, which involves the largest decrease in entropy? (A) 2 CO(g) + O2(g) → 2 CO2(g) (B) Pb(NO3)2(s) + 2 KI(s) → 2 KNO3(aq) + PbI2(s) (C) C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g) (D) 4 La(s) + 3 O2(g) → 2 La2O3(s)

4 La(s) + 3 O2(g) → 2 La2O3(s)

How many mL of 0.250 M Ba(NO3)2 solution are required to precipitate all the sulfate anions from 50.0 mL of 0.200 M H2SO4 solution? (A) 2.50 mL (B) 40.0 mL (C) 50.0 mL (D) 62.5 mL

40.0 mL

10 HI + 2 KMnO4 + 3 H2SO4 5 I2 + 2 MnSO4 + K2SO4 8 H2O According to the balanced equation above, how many moles of HI would be necessary to produce 2.5 mol of I2 starting with 4.0 mol of KMnO4 and 3.0 mol of H2SO4 (A) 20 (B) 10 (C) 5.0 (D) 2.5

5.0

A measured mass of an unreactive metal was dropped into a small graduated cylinder half filled with water. The following measurements were made. Mass of metal = 19.611 grams Volume of water before addition of metal = 12.4 milliliters Volume of water after addition of metal = 14.9 milliliters The density of the metal should be reported as (A) 7.844 grams per mL (B) 7.84 grams per mL (C) 7.8 grams per mL (D) 8 grams per mL

7.8 grams per mL

...CH3CH2COOH(l) + ...O2(g) → ...CO2(g) + ...H2O(l) How many moles of O2 are required to oxidize 1 mole of CH3CH2COOH according to the reaction represented above? (A) 2 moles (B) 5/2 moles (C) 7/2 moles (D) 9/2 moles

7/2 moles

Which of the following best describes the energy required to form the transition state in a chemical reaction? A) Free energy B) Ionization energy C) Kinetic energy D) Activation energy

Activation energy

4 NH3 + Cu2+ → Cu(NH3)4^2+ Which of the following statements regarding the reaction represented by the equation above is correct? (A) Nitrogen is reduced by Cu2+ (B) Copper gains electrons (C) Electrons are gained by the copper ion (D) Addition of acid would reverse the reaction

Addition of acid would reverse the reaction

Given equal concentration aqueous solutions of each, which of the following substances would be the WORST conductor of electricity in solution? (A) (NH4)2SO4 (B) KMnO4 (C) BaCO3 (D) Zn(NO3)2

BaCO3

Which describes the direction of changes in enthalpy and entropy for an endothermic dissolving process of an ionic solute in water at constant temperature? A) Enthalpy increases and entropy decreases B) Enthalpy decreases and entropy increases C) Both enthalpy and entropy decrease D) Both enthalpy and entropy increase

Both enthalpy and entropy increase

MnO2(s) + 4 H+(aq) + 2 Br-(aq) → Mn2+(aq) + Br2(g) + 2 H2O(l) Which of the following statements about the reaction above is true? (A) The reaction occurs in basic solution (B) Manganese is oxidized (C) Bromine loses electrons (D) Hydrogen is oxidized

Bromine loses electrons

A hydrocarbon gas with an empirical formula CH2 has a density of 1.88 grams per liter at 0°C and 1.00 atmosphere. A possible formula for the hydrocarbon is (A) CH2 (B) C2H4 (C) C3H6 (D) C4H8

C3H6

The metal aluminum is placed in a solution of hydrochloric acid. All of the following are true EXCEPT: (A) Aluminum increases in oxidation number (B) Chloride is a spectator ion (C) The reaction could be described as both a single replacement and a redox reaction (D) Chlorine gas is produced

Chlorine gas is produced

N2(g) + 3H2(g) → 2NH3(g) The reaction indicated above is thermodynamically favorable at 298 K, but becomes unfavorable at higher temperatures. Which of the following is true at 298 K? A) G, H, and S are all positive B) G, H, and S are all negative C) G and H are negative, but S is positive D) G and S are negative, but H is positive

G, H, and S are all negative

Which gives the thermodynamic parameters for the phase change in a system that begins as an open container of liquid water placed in a constant temperature environment of 230 K? A) G<0 B) S<0 C) G<0 and H<0 D) G<0, H<0, and S<0

G<0, H<0, S<0

Which of the following forms would have the greatest standard molar entropy? (A) H2(g) (B) H2(l) (C) H2O(g) (D) H2O(l)

H2O(g)

A student observes that an open container of water left overnight in the laboratory experienced a good deal of evaporation. Which of the following sets of contions best describes the thermodynamics of this evaporation event? A) H>0, S>0 B) H>0, S<0 C) H<0, S>0 D) H<0, S<0

H<0, S>0

Which of the following best describes the energy required to form the transition state in a chemical reaction? A) H>0, S>0 B) H>0, S<0 C) H<0, S>0 D) H<0, S<0

H<0, S>0

Which of the following completely ionizes in solution? (A) H2SO3 (B) HF (C) HNO2 (D) HClO4

HClO4

The energy diagram for the reaction X + Y → Z is shown above. The addition of a catalyst to this reaction would cause a change in which of the indicated energy differences? A) I only B) II only C) III only D) I and II only

I and II only

Which of the following would NOT cause an error in a titration experiment? I. Addition of base beyond the equivalence point II. Adding water to the acid once in the flask III. Choosing an indicator that changed color well beyond the equivalence point (A) I only (B) II only (C) III only (D) I and II only

II only

2 H+ + H2O2 + 2 Fe2+ → 2 Fe3+ + 2 H2O Which of the following is true regarding the reaction represented above? (A) The oxidation of O doesn't change (B) The oxidation number of H changes from -1 to +1 (C) Iron loses electron(s) (D) The number of electrons lost is greater than the electrons gained

Iron loses electron(s)

Which of the following is soluble in water? (A) AgCl (B) K2S (C) MgCO3 (D) CaSO4

K2S

A compound contains 1.10 mol of K, 0.55 mol of Te, 1.65 mol of O. What is the simplest formula of this compound? (A) KTeO (B) KTe2O (C) K2TeO3 (D) K4TeO6

K2TeO3

Consider the reaction 2 K3PO4(aq) + 3 Mn(NO3)2(aq) → Mn3(PO4)2(s) + 6 KNO3(aq) A precipitate is formed when 1.0 L of 0.20 M potassium phosphate solution is mixed with 0.5 L of 1.6 M manganese(II) nitrate solution. After the reaction occurs, which list ranks the ions remaining in solution in order of decreasing concentration? (A) NO3- > K+ > Mn^2+ > PO4^3- (B) Mn2+ > PO4^3- > K+ > NO3- (C) PO4^3- > Mn2+ > K+ > NO3- (D) NO3- > K+> PO4^3- > Mn

NO3- > K+ > Mn^2+ > PO4^3-

When solid ammonium chloride, NH4Cl(s) is added to water at 25°C, it dissolves and the temperature of the solution decreases. Which of the following is true for the values of ΔH and ΔS for the dissolving process? ΔH ΔS (A) Positive Positive (B) Positive Negative (C) Negative Positive (D) Negative Negative

Positive Positive

For which of the following processes would deltaS have a negative value? Reaction 1: 2Fe2O3(s) → 4Fe(s) + 3O2(g) Reaction 2:Mg^2+(aq) + 2OH-(aq) → Mg(OH)2(s) Reaction 3: H2(g) + C2H4(g) → C2H6(g) A) Reaction 1 only B) Reactions 1 and 2 only C) Reactions 1 and 3 only D) Reactions 2 and 3 only

Reactions 2 and 3 only

After completing an experiment to determine gravimetrically the percentage of water in a hydrate, a student reported a value of 38 percent. The correct value for the percentage of water in the hydrate is 51 percent. Which of the following is the most likely explanation for this difference? (A) Strong initial heating causing come of the hydrate sample to spatter out of the crucible. (B) The dehydrated sample absorbed some water after heating. (C) The crucible was not heated to constant mass before use. (D) Excess heating caused the dehydrated sample to decompose

The dehydrated sample absorbed some water after heating

6 I- + 2 MnO4- + 4 H2O(l) → 3 I2(s) + 2 MnO2(s) + OH- Which of the following statements regarding the reaction represented by the equation above is correct? (A) Iodide ion is oxidized by hydroxide ions. (B) MnO4- is oxidized by iodide ions. (C) The oxidation number of manganese changes from +7 to +2. (D) The oxidation number of iodine changes from -1 to 0.

The oxidation number of iodine changes from -1 to 0.

Samples of F2 gas and Xe gas are mixed in a container of fixed volume. The initial partial pressure of the F2 gas is 8.0 atmospheres and that of the Xe gas is 1.7 atmospheres. When all of the Xe gas reacted, forming a solid compound, the pressure of the unreacted F2 gas was 4.6 atmospheres. The temperature remained constant. What is the formula of the compound? (A) XeF (B) XeF3 (C) XeF4 (D) XeF6

XeF4

Compared to the value of H°f for H2O(s), the value of H°f for H2O(l) has the A) opposite sign and smaller absolute value B) same sign and smaller absolute value C) same sign and greater absolute value D) opposite sign and greater absolute value

same sign and smaller absolute value

Which of the following is a graph that describes the pathway of reaction that is endothermic and has high activation energy? (A) (B) (C) (D)

see endothermic graph (A)