For many purposes we can treat methane (CH4) as an ideal gas at temperatures above its boiling point of -161. °C. Suppose the temperature of a sample of methane gas is lowered from 92.0 °C to 74.0 °C, and at the same time the pressure is increased by 5.0%. O increase x10 Does the volume of the sample increase, decrease, or stay the same? O decrease x stays the same If you said the volume increases or decreases, calculate the percentage change in % the volume. Round your answer to the nearest percent.

A typical barometric pressure in Redding. California, is about 750 mm Hg. Calculate this pressure in atm and kPa.

You have a gas, one of the three known phosphorus-fluorine compounds (PF3, PF3, and P2F4). To find out which, you have decided to measure its molar mass. (a) First, yon determine that the density of the gas is 5.60 g/L at a pressure of 0.971 atm and a temperature of 18.2 C. Calculate the molar mass and identify the compound. (b) To check the results from part (a), you decide to measure the molar mass based on the relative rales of effusion of the unknown gas and CO2. You find that CO2 effuses at a rate of 0.050 mol/min, whereas the unknown phosphorus fluoride effuses at a rate of 0.028 mol/min. Calculate the molar mass of the unknown gas based on these results.

5-106 The normal boiling point of hexane, C6H14, is 69°C, and that of pentane, C5H12, is 36°C. Predict which of these compounds has a higher vapor pressure at 20°C.

he following demonstration takes place in a two-step process: rst, solid calcium carbide (CaC2j)reacts with liquid water to produce acetylene gas (C2H2)and aqueous calcium hydroxide. Second the acetylene gas produced is then ignited with a match, causing the combustion reaction of acetylene with oxygen gas to produce gaseous carbon dioxide and gaseous water. Write the balanced equations for each reaction that is occurring, including all phases. If a 100.0gsample of calcium carbide (CaC2)is initially reacted with 50.0gof water, which reactant is limiting? Now imagine that the final gases produced are collected in a large bulkier and allowed to cool to room temperature. Using the information from part b ( l00.0gof Cec2reacting with 50.0gof H2O), how many liters of carbon dioxide gas were produced in the balloon at a pressure of 1.00atm and 25C?

If equal masses of O2 and N2 are placed in separate containers of equal volume at the same temperature, which of the following statements is true? If false, explain why it is false. (a) The pressure in the flask containing N2 is greater than that in the flask containing O2. (b) There are more molecules in the flask containing O2 than in the flask containing N2.

5-111 Diving, particularly SCUBA (Self-Contained Underwater Breathing Apparatus) diving, subjects the body to increased pressure. Each 10. m (approximately 33 ft) of water exerts an additional pressure of 1 atm on the body. (a) What is the pressure on the body at a depth of 100. ft? (b) The partial pressure of nitrogen gas in air at 1 atm is 593 mm Hg. Assuming a SCUBA diver breathes compressed air, what is the partial pressure of nitrogen entering the lungs from a breathing tank at a depth of 100. ft? (c) The partial pressure of oxygen gas in the air at 2 atm is 158 mm Hg. What is the partial pressure of oxygen in the air in the lungs at a depth of 100. ft? (d) Why is it absolutely essential to exhale vigorously in a rapid ascent from a depth of 100. ft?

You have two pressure-proof steel cylinders of equal volume, one containing 1.0 kg of CO and the other containing 1.0 kg of acetylene, C2H2. (a) In which cylinder is the pressure greater at 25 C? (b) Which cylinder contains the greater number of molecules?

How many grams of water at 0C will be melted by the condensation of 1 g of steam at 100C?

5.19 A sample of CO2 gas has a pressure of 56.5 mm Hg in a 125-mL flask. The sample is transferred to a new flask, where it has a pressure of 62.3 mm Hg at the same temperature. What is the volume of the new flask?