Examples and Problems only

**Example #1:** A sample of gas at 25.0 °C has a volume of 11.0 L and exerts a pressure of 660.0 mmHg. How many moles of gas are in the sample?

**Example #2:** A sample of gas at 28.0 °C has a volume of 6.20 L and exerts a pressure of 720.0 mmHg. How many moles of gas are in the sample?

**Example #3:** Calculate the approximate volume of a 0.400 mol sample of gas at 11.0 °C and a pressure of 2.43 atm.

**Example #4:** Calculate the approximate temperature of a 0.300 mol sample of gas at 780. mmHg and a volume of 6.00 L.

**Example #5:** What is the pressure exerted by 2.3 mol of a gas with a temperature of 40. °C and a volume of 3.5 L?

**Example #6:** A sample of dry gas weighing 2.1025 grams is found to occupy 2.850 L at 22.00 °C and 740.0 mmHg. (a) How many moles of the gas are present? (b) What is the molar mass of the gas?

**Example #7:** An ideal gas has a density of 1.17 x 10¯^{6} g/cm^{3} at 1.00 x 10¯^{3} atm and 60.0 °C. Identify the gas.

**Example #8:** At STP, a 5.00 L flask filled with air has a mass of 543.251 g. The air in the flask is replaced with another gas and the mass of the flask is 566.107 g. The density of air is 1.29 g/L. What is the gas that replaced the air?

**Example #9:** A vessel at 25.0 °C is evacuated to a point where the amount of gas remaining is 5.00 x 10^{9} molecules per m^{3}. What is the pressure in the vessel?

**Example #10:** Of the following gases, which has density of 0.906 g/L at 315 K and 1.16 atm.

**Example #11:** A 0.105 g sample of an unknown diatomic gas contained in a 125 mL vessel has a pressure of 560 torr at 23 &175;C. What is the molar mass of the gas? What is the identity of the gas?

**Example #12:** If 1.0 g of each of the following gases is taken at STP, which one would occupy the greatest volume?

(a) CO

(b) H_{2}O

(c) CH_{4}

(d) NO

(e) They would all occupy the same volume.

**Example #13:** If 12.8 g of liquid helium at 1.7 K is completely vaporized. What volume does the helium occupy at STP?

**Example #14:** An elemental gas (meaning that it is made from one element) has a mass of 10.3 grams. It occupies 58.4 L at 1.00 atm and 2.50 °C. Identify the gas.

**Example #15:** An elemental gas (meaning that it is made from one element) has a mass of 10.3 grams. It occupies 4.27 L at 1.00 atm and 85.0 °C. Identify the gas.

**Bonus Example #1:** One of the methods for estimating the temperature at the center of the sun is based on the ideal gas equation. If the center is assumed to be a mixture of gases whose average molar mass is 2.04 g/mol, and the density and pressure are 1.14 g/cm^{3} and 2.01 x 10^{9} atm, respectively, calculate the temperature.

**Bonus Example #2:** (a) A gas has a temperature of 300. K and a pressure of 104 kPa. Find the volume occupied by 1.05 mol of this gas, assuming it is ideal. (b) Assuming the gas molecules can be approximated as small spheres of diameter 3.0 x 10¯^{10} m , determine the fraction of the volume found in part (a) that is occupied by the molecules.

**Problem #9a:** What is the value of and units on R? What is R called ("It's a letter" is not the correct answer!)?

**Problem #1:** Determine the volume of occupied by 2.34 grams of carbon dioxide gas at STP.

**Problem #2:** A sample of argon gas at STP occupies 56.2 liters. Determine the number of moles of argon and the mass of argon in the sample.

**Problem #3:** At what temperature will 0.654 moles of neon gas occupy 12.30 liters at 1.95 atmospheres?

**Problem #4:** A 30.6 g sample of gas occupies 22.414 L at STP. What is the molecular weight of this gas?

**Problem #5:** A 40.0 g gas sample occupies 11.2 L at STP. Find the molecular weight of this gas.

**Problem #6:** A 12.0 g sample of gas occupies 19.2 L at STP. What is the molecular weight of this gas?

**Problem #7:** 96.0 g. of a gas occupies 48.0 L at 700.0 mm Hg and 20.0 °C. What is its molecular weight?

**Problem #8:** 20.83 g of a gas occupies 4.167 L at 79.97 kPa at 30.0 °C. What is its molecular weight?

**Problem #9:** What is often called the Ideal Gas Constant is 0.0820574 L atm mol¯^{1} K¯^{1}. What is often called the Universal Gas Constant is 8.31451 J mol¯^{1} K¯^{1}. Convert the Ideal Gas Constant into the Universal Gas Constant and vice versa.

**Problem #10:** 5.600 g of solid CO_{2} is put in an empty sealed 4.00 L container at a temperature of 300 K. When all the solid CO_{2} becomes gas, what will be the pressure in the container?

**Bonus Problem #1:** 2.035 g H_{2} produces a pressure of 1.015 atm in a 5.00 L container at -211.76 °C. What will the temperature (in °C) have to be if an additional 2.099 g H_{2} are added to the container and the pressure increases to 3.015 atm.

**Bonus Problem #2:** 1.00 mole of gas occupies 22.414 L at STP. Calculate the temperature and pressure conditions needed to fit 2.00 moles of a gas into a volume of 22.414 L.

**Problem #11:** How many moles of gas are contained in 890.0 mL at 21.0 °C and 750.0 mm Hg pressure?

**Problem #12:** 1.09 g of H_{2} is contained in a 2.00 L container at 20.0 °C. What is the pressure in this container in mmHg?

**Problem #13:** Calculate the volume 3.00 moles of a gas will occupy at 24.0 °C and 762.4 mm Hg.

**Problem #14:** How many moles of gas would be present in a gas trapped within a 100.0 mL vessel at 25.0 °C at a pressure of 2.50 atmospheres?

**Problem #15:** How many moles of a gas would be present in a gas trapped within a 37.0 liter vessel at 80.00 °C at a pressure of 2.50 atm?

**Problem #16:** What volume will 1.27 moles of helium gas occupy at STP?

**Problem #17:** At what pressure would 0.150 mole of nitrogen gas at 23.0 °C occupy 8.90 L?

**Problem #18:** What volume would 32.0 g of NO_{2} gas occupy at 3.12 atm and 18.0 °C?

**Problem #19:** How many moles of gas are contained in a 50.0 L cylinder at a pressure of 100.0 atm and a temperature of 35.0 °C? If the gas weighs 79.14 g, what is its molecular weight?

**Problem #20:** An amount of an ideal gas at 290.9 K has a volume of 17.05 L at a pressure of 1.40 atm. What is the pressure of this gas sample when the volume is halved and the absolute temperature is multipled by four?

**Problem #21:** A balloon has a mass of 0.5 g when completely deflated. When it is filled with an unknown gas, the mass increases to 1.7 g. You notice on the canister of the unknown gas that it occupies a volume of 0.4478 L at a temperature of 50 °C. You note the temperature in the room is 25 °C. Identify the gas.

**Problem #22:** A 10.20 g sample of a gas has a volume of 5.25 L at 23.0 °C and 751 mmHg. If 2.30 g of the same gas is added to this constant 5.25 L volume and the temperature raised to 67.0 degrees Celsius, what is the new gas pressure?

**Problem #23:** A gas consisting of only carbon and hydrogen has an empirical formula of CH_{2}. The gas has a density of 1.65 g/L at 27.0 °C and 734.0 torr. Determine the molar mass and molecular formula of the gas.

**Problem #24:** 13.9 grams of an unknown gas is placed in a 5.00 L container.It has an initial pressure at 58.6 kPa and initial temperature at 60.0 °C. What is the name of this gas?

**Problem #25:** A 19.5 L flask at 15 °C contains a mixture of three gases: N_{2} (2.50 mol), He (0.38 mol), and Ne (1.34 mol). Calculate the partial pressure of neon gas in the mixture.

**Problem #26:** A 1.00 L flask is filled with 1.25 g of argon at 25.0 °C. Ethane vapor is then added to the same flask until the total pressure is 1.050 atm. What is the mass of ethane that was added to the flask?

**Problem #27:** An experiment was performed to determine the value for R in the Ideal Gas Law. An excess of HCl(aq) was reacted with a piece of magnesium ribbon and the hydrogen gas released in the reaction was collected over water.

The following data were collected (100. cm of ribbon weighs 1.89 g):

P _{room}753.0 mmHg T _{room}22.7 °C V _{gas}30.00 mL Mg ribbon 1.55 cm

**Bonus Problem #1:** The vapor pressure of water at 25 °C is 23.76 torr. If 1.50 g of water is enclosed in a 2.0 L container, will any liquid be present? If so, what mass of liquid?

**Bonus Problem #2:** Container A holds N_{2} gas with a mass of 56.2 g and is 4.4 times the volume of container B which holds argon (Ar) gas at the exact same temperature and pressure. What is the mass of the Ar (in g) within container B?