Test #3 Chem I

What is the enthalpy change when 49.4 mL of 0.430 M sulfuric acid reacts with 23.3 mL of 0.309 M potassium hydroxide? H2SO4(aq) + 2KOH(aq) --> K2SO4(aq) + 2H20(l) ΔH = -111.6 kJ/mol

-0.402 kJ

Consider the following processes: 2A--> (1/2)B + C ΔH1 = 5 kJ/mol (3/2)B + 4C --> 2A + C + 3D ΔH2 = -15 kJ/mol E + 4A --> C ΔH3 = 10 kJ/mol Calculate ΔH for: C--> E + 3D

-10 kJ/mol

A gas absorbs 0.0 J of heat and then performs 30.7 J of work. The change in internal energy of the gas is

-30.7 J

Consider a sample of helium gas in a container fitted with a piston, as pictured below. The piston is frictionless, but has a mass of 10.0kg. How many of the following processes will cause the piston to move away from the base and decrease the pressure of the gas? Assume ideal behavior. I. heating the helium II. removing some of the helium from the container III. turning the container on its side IV. decreasing the pressure outside the container

1

The local weather forecaster reports that the current barometric pressure is 30.4 inches of mercury. What is the current pressure in atmospheres?

1.02

Calculate the density of nitrogen at STP

1.25 g/L

body temperature is about 309 K. On a cold day, what volume of air at 276 K must a person with a lung capacity of 2.2 L breathe in to fill the lungs?

1.97 L

Which of the following would represent the greatest pressure?

11.4 psi

What volume of H20(g) measured at STP is produced by the combustion of 6.27g of natural gas (CH4) according to the following equation? CH4(g) + 2O2(g) --> CO2 +2H2O(g)

17.5 L

For an ideal gas, which pairs of variables are inversely proportional to each other (if all other factors remain constant)? 1. V and T 2. T and n 3. n and V 4. P and T

2 only

A balloon has the 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

A sample of oxygen has a volume of 1.72 L at 27 C and 800.0 torr. How many oxygen molecules does it contain?

4.43 x 10^22

Calculate the root mean square velocity for the O2 molecules in a sample of O2 gas at 11.8 C. (R = 8.3145 J/K mol)

471.2 m/s

The mass of 1.12 liters of gas Y at STP is found to be 6.23 g. Calculate density of gas Y.

5.56 g/l

One mole of an ideal expanded from a volume of 1.00 liter to a volume of 8.93 liters against a constant external pressure of 1.00 atm. How much work (in joules) is performed on the surroundings? Ignore significant figures for this problem. (T = 300 K; 1 L x atm = 101.3 J)

803 J

All of the following statements about the greenhouse effect are true except: A. It occurs only on earth. B. The molecules H2O and CO2 play an important role in retaining the atmosphere's heat. C. Low humidity allows efficient radiation of heat back into space. D. The carbon dioxide content of the atmosphere is quite stable. E. A and D

A and D

According to the first law of thermodynamics, the energy of the universe is constant. Does this mean that ΔE is always equal to zero?

No, ΔE does not always equal zero because it refers to the system's internal energy, which is affected by heat and work.

Which statement is true of a process in which one mole of a gas is expanded from state A to state B?

The final volume of the gas will depend on the path taken.

One of the main advantages of hydrogen as a fuel is that:

The only product of hydrogen combustion is water.

Which of the following statements is correct?

The system does work on the surroundings when an ideal gas expands against a constant external pressure.

Dalton's law of partial pressures states that:

The total pressure of a mixture of gases is the sum of the partial pressures of all of the gaseous compounds.

Boyle's law states that

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

Which of the following is both a greenhouse gas and a fuel?

methane

Graham's law states that:

the rates of effusion of gases are inversely proportional to the square roots of their molar masses.

For a particular process q = 20 kJ and w = 15 kJ. Which of the following statements is true?

ΔE = 35 kJ

Ordering the following in increasing rate of effusion: F2, Cl2, NO, NO2, CH4

Cl2 < NO2 < F2 < NO < CH4

For which gas do the molecules have the highest average velocity? He Cl2 CH4 NH3 all gases the same

He

Which of the following properties is (are) intensive properties? I. mass II. temperature III. volume IV. energy

II and IV (temperature and concentration)

Consider the reaction: C2H5OH(l) + 3O2(g) --> 2CO2(g) + 3H2O(l); ΔH = -1.37 x 10^3 kJ Consider the following propositions: I. The reaction is endothermic II. The reaction is exothermic III. The enthalpy term would be different if the water formed was gaseous. Which of these propositions is (are) true?

II, III

A 45.9 g sample of a metal is heated to 95.2 C and then placed in a calorimeter containing 120.0 g of water (c = 4.18 J/g C) at 21.6 C. The final temperature of the water is 24.5 C. Which metal was used?

Iron (c = 0.45 J/g C)

For which gas do the molecules have the smallest average kinetic energy? He Cl2 CH4 NH3 all gases the same

all gases the same

Which gas sample has the greatest number of molecules? He Cl2 CH4 NH3 all gases the same

all gases the same

Which of the following is not being considered as an energy source for the future?

carbon dioxide

The fossil fuels was formed from the remains of plants that were buried and exposed to high pressure and heat over time.

coal

Real gases are those that

deviate from ideal behavior