Question

Two balloons, one containing 1.54 L hydrogen gas and the other containing 0.72 L of
helium gas, are at the same pressure and temperature conditions. If the second balloon
contains 0.100 mol of helium, then the mass of hydrogen gas in the first balloon is:
A. 0.43 g
B. 0.22 g
C. 0.094 g
D. 0.047 g

Answer 1

Answer:

A.) 0.43 g

Explanation:

Before you can calculate the mass, you need to find the moles. You can do this by using Avogadro's Law:

V₁ / n₁ = V₂ / n₂

In this equation, "V₁" and "n₁" represent the first balloon's volume and mole value. "V₂" and "n₂" represent the second balloon's volume and mole value. Since you are searching for the first balloon's mole value, you can plug the other values into the equation and simplify to find n₁.

V₁ = 1.54 L                         V₂ = 0.72 L

n₁ = ? moles                      n₂ = 0.100 moles

V₁ / n₁ = V₂ / n₂                                               <----- Avogadro's Law

1.54 L / n₁ = 0.72 L / 0.100 moles                 <----- Insert values

1.54 L / n₁ = 7.2                                              <----- Simplify right side

1.54 L = 7.2 x n₁                                              <----- Multiply both sides by n₁

0.214 = n₁                                                       <----- Divide both sides by 7.2

Now, you can find the mass using the molar mass of the gas. Remember, hydrogen exists as a diatomic molecule.

Atomic Mass (H₂): 2(1.008 g/mol)

Molar Mass (H₂): 2.016 g/mol

0.214 moles He            2.016 g
--------------------------  x  -----------------  =  0.43 g H₂
                                       1 mole