3 chemistry assignments due in 48 hours

Name _______________________________________ Date ______________ Class Period ______

Gas Law Problems Directions: This MUST be handwritten. For each problem, write the formula, list variables and values with units, substitute values into the formula, including units, solve and include the correct # sig. figs. and units. Submit with your name on your paper and your I.D. Do not cover up any work.

INFORMATION FOR GAS LAWS PROBLEMS

Units of Pressure: 1 atm = 760.0 mm Hg = 101.3 kPa= 760 .0 torr STP = Standard Temperature and Pressure, (0 ℃ and 1 atm)

For all Gas Laws problems, temperature must be in Kelvin: K = ◦C + 273 If you are to report a final answer in degrees Celsius, use this calculation: °C = K - 273

Boyle’s Law: When temperature is held constant, pressure and volume are inversely proportional. As volume increases, pressure decreases, and as volume decreases, pressure increases.

P1V1= P2V2 You will always be given 3 of the 4 variables. Read the problem carefully.

P1 = initial (starting) pressure V1 = initial (starting) volume P2 = final pressure V2 = final volume

1) What pressure is required to compress 196.0 liters of air at 1.00 atmosphere into a cylinder whose volume is 26.0 liters?

2) A 40.0 L tank of ammonia has a pressure of 12.7 kPa. Calculate the volume of the ammonia if its pressure is changed to 8.4 kPa while its temperature remains constant.

Charles’ Law: When pressure is held constant, volume and temperature are directly proportional. *If temperature increases, volume increases, and if temperature decreases, volume decreases. Formulas: use either of the following formulas for Charles’ Law problems.

V1 = initial (starting) volume T1 = initial (starting) temperature (in Kelvin) V2 = final volume T2 = final temperature (in Kelvin)

3) A container containing 5.00 L of a gas is collected at 100 K and then allowed to expand to 20.0 L. What must the new temperature be in order to maintain the same pressure (as required by Charles' Law)?

Name _______________________________________ Date ______________ Class Period ______ 4) A gas occupies 900.0 mL at a temperature of 27.0 °C. What is the volume at 132.0 °C?

Gay-Lussac’s Law: When volume is held constant, the pressure of a gas increases as the temperature increases, and decreases as temperature decreases.

or P1T2 = P2T1

P1 = initial (starting) pressure T1 = initial (starting) temperature (in Kelvin) P2 = final pressure T2 = final temperature (in Kelvin)

5) If a container of neon gas at 25.0 °C has a pressure of 2.50 atm, what will the pressure be if the temperature is raised to 40.0 °C ?

6) If nitrogen at 20oC and a pressure of 748 mm Hg is compressed to 725 mm Hg at constant volume, what is the new temperature? Report the final temperature in oC.

Combined Gas Law: can be used to calculate any of the gas laws problems.

or P1V1T2 = P2V2,T1

P1 = initial (starting) pressure V1 = initial (starting) volume T1 = initial (starting) temperature (in Kelvin) P2 = final pressure V2 = final volume T2 = final temperature (in Kelvin)

7) A gas balloon has a volume of 106.0 liters when the temperature is 45.0 °C and the pressure is 740.0 mm of mercury. What will its volume be at 20.0 °C and 780 .0 mm of mercury pressure?

Name _______________________________________ Date ______________ Class Period ______ 8) If 10.0 liters of oxygen at STP are heated to 512 °C, what will be the new volume of gas if the pressure is also increased to 1520.0 mm of mercury?

Ideal Gas Law PV = nRT P = pressure (atm or kPa)

V = volume (L) n = moles *R = constant T = Temperature (K)

*If pressure is given in atm, use R = 0.0821 L*atm/(K*mol) *If pressure is given in kPa, use R =8.31 L*kPa /(K*mole)

Use the ideal gas law, and the universal gas constant to solve the following problems: 9) What is the temperature of 4.0 moles of a gas at a pressure of 5.60 atm and a volume of 12.0 liters?

10) Calculate the moles of gas at a pressure of 121.6 kPa, a volume of 31.0 liters, and a temperature of 87.0 oC.