Comparing Mass: Oxygen vs Methane at STP

05 Jun 2021

How do I determine the mass that has the same mass 11.2 L of O₂ at STP?

Which of the following volumes of Methane, CH₄ at STP, has the same mass as 11.2 L of O₂ at STP?

1) 11.2 L of Methane at STP

2) 22.4 L of Methane at STP

3) 33.6 L of Methane at STP

4) 44.8 L of Methane at STP

To determine the mass that has the same mass as 11.2 L of O₂ at STP, we need to compare the mass of oxygen to different volumes of methane at STP.

First, let's find the mass of 11.2 L of O₂ at STP:

Volume of O₂ = 11.2 L

Mole of O₂ = 11.2 L / 22.4 L = 0.5 mole

Molar mass of O₂ = 32 g/mol

Mass of O₂ = 0.5 mole × 32 g/mol = 16 grams

Now, let's calculate the mass of different volumes of methane:

For 11.2 L of Methane, CH₄:

Mole of CH₄ = 11.2 L / 22.4 L = 0.5 mole

Mass of CH₄ = 0.5 mole × 16 g/mol = 8 grams

For 22.4 L of Methane, CH₄:

Mole of CH₄ = 22.4 L / 22.4 L = 1 mole

Mass of CH₄ = 1 mole × 16 g/mol = 16 grams

For 33.6 L of Methane, CH₄:

Mole of CH₄ = 33.6 L / 22.4 L = 1.5 moles

Mass of CH₄ = 1.5 moles × 16 g/mol = 24 grams

For 44.8 L of Methane, CH₄:

Mole of CH₄ = 44.8 L / 22.4 L = 2 moles

Mass of CH₄ = 2 moles × 16 g/mol = 32 grams

Therefore, 11.2 L of O₂ at STP has the same mass as 22.4 L of Methane, CH₄ (2nd option).