MATH PROBLEMS: Show your work for these numerical problem items 1-7.

• A sample of gas has a volume of 6.20 L at 20°C at a pressure of 1.10 atm. What is its volume at the same temperature and at a pressure of 0.925 atm? (Hint: What equation will you use if the temperature is constant?).
• A gas syringe at 20°C contains 20.0 mL of CO2 gas. The pressure of the gas in the syringe is 1.0 atm. What is the pressure in the syringe at 20°C if the plunger is depressed to 10.0 mL?
• A sample of the inhalation anesthetic gas Halothane, in a 500-mL cylinder has a pressure of 2.3 atm at 0°C. What will be the pressure of the gas if its temperature is warmed to 37°C (body temperature)? (Hint: Which law will you apply if the volume is constant?)
• A certain quantity of helium gas is at a temperature of 27°C and a pressure of 1.00 atm. What will the new temperature be if its volume is doubled at the same time that its pressure is decreased to one-half its original value? (Hint: Three variables have been given so what equation will you use?)
• A 26.4-mL sample of ethylene gas, C2H4, has a pressure of 2.50 atm at 2.5°C. If the volume is increased to 36.2 mL and the temperature is raised to 10°C, what is the new pressure. (Hint: Three variables have been given so what equation will you use?)
• A sample of a gas at 77°C and 1.33 atm occupies a volume of 50.3 L. How many moles of the gas are present? (Hint: Since moles have been asked, which equation has the moles listed in the equation. Use that to solve this problem).
• A hyperbaric chamber has a volume of 200. L. (a) How many moles of oxygen are needed to fill the chamber at room temperature (23°C) and 3.00 atm pressure? (b) How many grams of oxygen are needed? (Hint: Since moles have been asked, which equation has the moles listed in the equation. Use that to solve this problem. Also don’t forget to use the equation 1 mole = Formula weight or Molecular weight to calculate the grams of O2).

Dr. Eve Carter PhD, Applied Mathematics
Senior lecturer at University. 12+ years tutoring algebra and calculus..

Aug 27, 2025