Phase Changes Answers

A balloon containing helium gas expands from 230 mL to 860 mL as more helium is added. What was the initial quantity of helium present if the expanded balloon contains 3.8 × 10 mol, assuming constant temperature and pressure?Use the formula:

Temperature is .

Volume is .

Moles are .

Identify the ideal gas law equation.

Use your understanding of the ideal gas law to identify the correct relationships among the variables. Pressure is .

How many moles of oxygen must be placed in a 3.00 L container to exert a pressure of 2.00 atm at 25.0°C?Formula: PV = nRT(R = 0.0821 Latm/molK) Which variables are given?

Solve the problem for the moles of oxygen. mol O2

A sample of gas contains 6.25 × 10-3 mol in a 500.0 mL flask at 265°C. What is the pressure of the gas in kilopascals?Formula: PV = nRT(R = 8.31 LkPa/molK)Which variables are given?

A rigid, 2.50 L bottle contains 0.458 mol He. The pressure of the gas inside the bottle is 1.83 atm. If 0.713 mol Ar is added to the bottle and the pressure increases to 2.05 atm, what is the change in temperature of the gas mixture? Use the correct number of significant digits.Formula: PV = nRT(R = 0.0821 Latm/molK)The initial temperature of the gas is K.

Which variables are unknown?

Which variables are unknown?

The final temperature of the gas is K.

The temperature change is K.

Solve the problem for the pressure of oxygen. kPa