# Calculating the volume, temperature, and density of liquids and gasses

a) Which of the following is not a unit of pressure?

atm

torr

mm Hg

Pascal

all of these are units of pressure

b) What device is used to measure atmospheric pressure?

c) What pressure (atm) is exerted by a column of ethanol 55.0 cm high? The density of ethanol is 0.789 g/cm3 and 9.8m/s2 as your gravitational constant. Round to three decimal places, do not include units or commas in your answer.

d) True or False, use only capital T or F:

The relationship between volume and pressure (At constant temperature) is directly proportional.

The relationship between pressure and temperature (At constant volume) is inversely proportional.

The relationship between volume and temperature (At constant pressure) is directly proportional.

e) A 33.5 cm3 bubble of air at 1.3 atm pressure is subjected to a new pressure of 4.6 atm. What will be the new volume (cm3)? Assume constant temperature. Do not include units, round to one decimal place.

f) A balloon is filled with 1.8 cm3 helium gas at 100 atm pressure. What will be the new pressure (atm) if the volume is changed to 62.5 cm3? Round to one decimal place, do not include units or commas in your answer.

g) What volume (In Liters) of oxygen must react to form 17.0L of carbon dioxide according to the following balanced equation: 2CO(g) + O2(g) --> 2CO2(g)

Assume an excess of CO and that all are at the same temperature and pressure. Round to one decimal place, do not include units in your answer.

h) What volume (In Liters) of hydrogen must react to form 4.0L of ammonia according to the following balanced equation: N2(g) + 3H2(g) --> 2NH3(g) Assume an excess of N2 and that all are at the same temperature and pressure. Round to one decimal place, do not include units in your answer.

i) A 20.3 cm3 bubble under the ocean at 2.7 atm and 10.4oC surfaces to 1.0 atm and 28.1oC. What is the new volume (in cm3)? Round to one decimal place, do not include units in your answer.

j) At what temperature (oC) will a gas sample occupy 5.6 L if it originally occupies 16.6 L at 34.7oC? Round to one decimal place, do not include units in your answer.

k) A balloon at constant temperature is subjected to a pressure drop. The resulting volume will be ________ the original volume of the balloon.

l) What volume (In ml) of carbon dioxide will form if 66.4 ml of O2 are reacted acccording to the following balanced equation: 2CO(g) + O2(g) --> 2CO2(g)

Assume an excess of CO and that all are at the same temperature and pressure. Round to one decimal place, do not include units in your answer.

m) At 16°C a sample of ammonia gas exerts a pressure of 11.7 atm. What is the pressure when the volume of the gas is reduced to one-fourth of the original value at the same temperature. Round to one decimal place, do not include units in your answer.

n) A sample of nitrogen gas (N2) kept in a container of volume 6 L and at a temperature of 27.9°C exerts a pressure of 2.5 atm. Calculate the number of grams of gas present. Round to one decimal place, do not include units in your answer. For molar mass, use the periodic table in the front of your text to two decimal places. For constants, use the appendix in the back of your text

o) A volume of 0.208 L of a gas at STP weighs 0.474 g. Calculate the molar mass of the gas. Round to one decimal place do not include units.

Lithium hydride reacts with water as follows.

LiH(s) + H2O(l) -->LiOH(aq) + H2(g)

p) During World War II, U.S. pilots carried LiH tablets. In the event of a crash landing at sea, the LiH would react with the seawater and fill their life belts and lifeboats with hydrogen gas. How many grams of LiH are needed to fill a 4 L life belt with hydrogen gas at 0.93 atm and 20.2°C? Round to two decimal places, do not include units in your answer.

q) Which of the following gases will occupy the smallest volume at 300 K and 760 torr and why?

- 80 g diatomic oxygen .

- 80 g methane .

- 80 g hydrogen fluoride .

- All gases will occupy the same volume

#### Solution Preview

a) All are units of pressure

b) A manometer is used to measure atmospheric pressure

c) Pressure = density x gravity x height = 42527.1 g / cm s^2 = 4252.71 kg / m s^2 = 4252.71 Pa = 0.042 atm

d) The relationship between volume and pressure (at constant temperature) is directly proportional. False

The relationship between pressure and temperature (at constant volume) is inversely proportional. False

The relationship between volume and temperature (at constant ...