AP Chemistry Chapter 6 Test

From the following enthalpies of reaction: H2(g) + F2(g) 🡪 2 HF (g) -537 C(s) + 2 F2(g) 🡪 CF4(g) -680 2 C(s) + 2 H2(g) 🡪 C2H4(g) 52.3 Calculate ΔH for the reaction of ethylene with F2: C2H4(g) + 6 F2 (g) 🡪 2 CF4(g) + 4 HF(g)

-2486.3

A 110. g sample of copper (s = 0.20 J/g∙˚C) is heated to 82.4℃ and then placed in a container of water at 22.3℃. The final temperature of the water and copper is 24.9℃. What is the mass of the water in the container, assuming that all the heat lost by the copper is gained by the water?

116.37 grams

The value of ΔH° for the following reaction is -3351 kJ: 2Al (s) + 3O2 (g) 🡪 2Al2O3 (s) The value of ΔH°f for 1.0 mol of Al2O3 is kJ. a) -1676 b) -3351 c) -32.86 d) -335.1 e) -16.43

a) -1676

Given the following reactions: N2 (g) + O2 (g) 🡪 2NO (g) ΔH = +180.7 kJ 2NO (g) + O2 (g) 🡪 2 NO2 (g) ΔH = -113.1 kJ The enthalpy of reaction for the reaction below is___ kJ. 4NO (g) 🡪 2NO2 (g) + N2 (g) a) -293.8 b) 293.8 c) -45.5 d) 45.5 e) 67.6

a) -293.8

Given the following reactions: Fe2O3 + 3CO 🡪 2Fe + 3CO2 ΔH = -28.0 kJ 3Fe + 4CO2 🡪 4CO + Fe3O4 ΔH = +12.5 kJ The enthalpy of reaction for the reaction below is ___ kJ. 3Fe2O3 + CO 🡪 CO2 + 2Fe3O4 a) -59.0 b) 40.5 c) -15.5 d) -109

a) -59.0

The average fuel value of sugar is 17kJ/g. A 2.0L pitcher of sweetened Kool-aid contains 400 g of sugar. What is the fuel value (in kJ) of a 500mL serving of Kool-aid? (assume that the sugar is the only fuel source). a) 1700 b) 1700000 c) 17 d) 170 e) 42000

a) 1700

The specific heat capacity of methane gas is 2.20 J/g·K. How many joules of heat are needed to raise the temperature of 5.00g of methane from 36.0 °C to 75.0°C. a) 429 b) 88.6 c) 0.0113 d) 22.9 e) 1221

a) 429

A chemical reaction that absorbs heat from the surrounding is said to be ___ and has a ___ ΔH at constant pressure. a) Endothermic, positive b) Endothermic, negative c) Exothermic, negative d) Exothermic, positive e) Exothermic, neutral

a) Endothermic, positive

Which of the following has the most energy? a) Fats b) Carbohydrates c) Proteins d) All of these have equal amounts of energy

a) Fats

Which of the following fuels will have the greatest fuel value? a) Hydrogen b) Charcoal c) Bituminous coal d) Natural gas e) Wood

a) Hydrogen

Which of the following conditions would definitely result in an increase in the internal energy of a system? a) The system gains heat and has work done on it by the surroundings. b) The system gains heat and does work on the surroundings. c) The system loses heat and has work done on it by the surroundings. d) The system loses heat and does work on the surroundings. e) None of these

a) The system gains heat and has work done on it by the surroundings.

For which of the following reactions is the ΔH°rxn equal to ΔH°f for the product? a) Xe (g) + 2F2(g) 🡪 XeF4 (g) b) CH4 (g) + 2Cl2 (g) 🡪 CH2Cl2 (l) + 2HCl (g) c) N2 (g) + O3 (g) 🡪 N2O3 (g) d) 2CO (g) + O2 (g)🡪 2CO2 (g)

a) Xe (g) + 2F2(g) 🡪 XeF4 (g)

Given the data in the table below, ΔH°rxn for the reaction is kJ. SO3 (g) + H2O (l) 🡪 H2SO4 (l) Substance ΔH°rxn SO2 -297 SO3 -396 SO2Cl2 -364 H2SO4 -814 H2O -286 a) 704 b) -132 c) -2160 d) 1496 e) -704

b) -132

When 81 g of a metal at 94.0 °C is added to 100 g of water at 25.0°C, the final temperature is found to be 29.8°C. What is the heat capacity per gram of the metal? (heat capacity of water = 4.184 J/g·°C)? a) 0.461 J/g·°C b) 0.386 J/g·°C c) 0.350 J/g·°C d) 1.97 J/g·°C

b) 0.386 J/g·°C

What is the change in internal energy of a system that loses 50 J of heat and has 150J of work performed on it by the surroundings? a) 50 b) 100 c) -100 d) -200

b) 100

Under what condition(s) is the enthalpy change of a process equal to the amount of heat transferred? a) Constant temperature b) Constant pressure c) Constant volume d) A and B e) B and C

b) Constant pressure

Which of the following is the most accurate statement of Hess's Law? a) The enthalpy of a reaction depends on the physical states of the reactants and products. b) If a reaction is carried out in individual steps, the enthalpy for the reaction will equal the sum of the enthalpy changes for the individual steps. c) The enthalpy for a process in the forward direction is equal to the enthalpy change for the process in the reverse direction. d) None of these

b) If a reaction is carried out in individual steps, the enthalpy for the reaction will equal the sum of the enthalpy changes for the individual steps.

Given the data in the table below, ΔH°rxn for the reaction is kJ. IF5 (g) + F2 (g) 🡪 IF7 Substance ΔH°rxn IF -95 IF5 -840 IF7 -941 F2 0 a) 1801 b) -1801 c) -101 d) -121 e) 121

c) -101

The combustion of titanium with oxygen produces titanium dioxide: Ti (s) + O2 (g) 🡪 TiO2 (s) When .910 g of titanium is combusted in a bomb calorimeter, the temperature of the calorimeter increases from 25.0°C to 53.8°C. In a separate experiment, the heat capacity of the calorimeter is measured to be 9.84kJ/K. The heat of reaction for the combustion of a mole of Ti in this calorimeter is ___ kJ/mol. a) 4.98 b) 2.67 c) -14900 d) -311 e) -0.154

c) -14900

Given the data in the table below, ΔH°rxn for the reaction is kJ. Ag2O (s) + H2S (g) 🡪 Ag2S (s) + H2O (l) Substance ΔH°rxn Ag2O -31.0 Ag2S -32.6 H2S -20.6 H2O -286 a) -320 b) -202 c) -267 d) -308 e) More data is needed to complete the calculation

c) -267

The value of ΔH° for the following reaction is -186 kJ. Calculate the heat (kJ) released from the reaction of 25 g of Cl2. H2 (g) + Cl2 (g) 🡪 2HCl (g) a) -186 b) 530 c) -66 d) -33 e) 47

c) -66

Determine the Kinetic Energy (in J) of an 80 g bullet traveling at 300m/s. a) 3600000 b) 12000 c) 3600 d) 12

c) 3600

The specific heat capacity of liquid water is 4.18 J/g·K. How many joules of heat are needed to raise the temperature of 5.00g of water from 25.1 °C to 65.3°C. a) .0208 b) 48.1 c) 840 d) 1890 e) 54.4

c) 840

The change in the internal energy of a system that releases 2500 J of heat and that does 7655 J of work on the surroundings is J. a) 10155 b) 5155 c) -5155 d) -10155

d) -10155

At what velocity (m/s) must a 20.0 g object be moving in order to possess a kinetic energy of 1.00 J? a) 1.00 b) 50.0 c) 10000 d) 10.0 e) 1000

d) 10.0

A 5-ounce cup of raspberry yogurt contains 6.0 g of protein, 2.0 g of fat, and 26.9 g of carbohydrate. The fuel values for protein, fat, and carbohydrate are 17, 38, and 17 kJ/g, respectively. The fuel value of this cup of yogurt is kJ. a) 830 b) 72 c) 720 d) 640 e) 600

d) 640

The first law of thermodynamics states: a) All reactions are exothermic b) All reactions produce work c) The work done by a reaction equals the amount of heat it produces d) Energy is not created or destroyed in a reaction

d) Energy is not created or destroyed in a reaction

When a system ___ , ΔE is always negative. a) Absorbs heat and has work done on it b) Absorbs heat and does work c) Gives off heat and has work done on it d) Gives off heat and does work

d) Gives off heat and does work

The specific heat capacity of copper metal is 0.385 J/g·K. How many joules of heat are needed to raise the temperature of a 1.55 kg block of copper from 33.0° C to 77.5°C. a) 0.00558 b) 179000 c) .00000558 d) 26.6 e) 26600

e) 26600

The value of ΔH° for the reaction is -72 kJ. ___ of heat are released when 1.0 mol of HBr is formed in this reaction. H2 (g) + Br2 (g) 🡪 2HBr (g) a) 72 b) 0.44 c) 18 d) 144 e) 36

e) 36

Internal energy can be increased by: a) Transferring heat from the surroundings to the system b) Transferring heat from the system to the surroundings c) Doing work on the system d) Both A and B e) Both A and C

e) Both A and C

Enthalpy is typically 0 for elements in their natural state. For the species below, ΔHf° is most likely zero for . 2 Co (s) + H2 (g) + 8PF3 (g) 🡪 2 HCo(PF3)4 (l) a) PF3 b) HCo(PF3)4 c) H2 d) Co e) Both Co and H2

e) Both Co and H2