# Homework Help: Gas law calculation problem

1. Dec 9, 2016

### ChloeYip

1. The problem statement, all variables and given/known data

1) A 5.0- liter gas tank holds 1.7 moles of monatomic helium (He) and 1.10 mole of diatomic oxygen

(O2), at a temperature of 260 K. The ATOMIC masses of helium and oxygen are 4.0 g/mol and

16.0 g/mol, respectively. What is the ratio of the root- mean- square (thermal) speed of helium to

that of oxygen?

A) 2.0 B) 5.6 C) 2.8 D) 4.0 E) 1.4

2) A 25- L container holds ideal hydrogen (H2) gas at a gauge pressure of 0.25 atm and a

temperature of 0°C. What mass of hydrogen gas is in this container? The ATOMIC mass of

hydrogen is 1.0 g/mol, the ideal gas constant is R = 8.314 J/mol•K = 0.0821 L ∙ atm/mol ∙ K, and

1.00 atm = 101 kPa.

A) 1.4 g B) 6.3 g C) 4.2 g D) 2.8 g E) 5.6 g

2. Relevant equations
Gas law? I don't know.

3. The attempt at a solution
I have no idea at all.

I would greatly appreciated if you can provide with detailed steps to solve the question.
Thank you very much.