Question

Hydrogen gas and oxygen gas combine according to this reaction: 2H2(g]+O2(g]→2H2O(l]At STP, a chemist mixes 3.74 L of hydrogen gas with excess oxygen gas. How many liters of oxygen gas will react?

Answer 1

Answer:

1.47 Liters of O₂ were reacted

Explanation:

The reaction is:

2H₂ (g) + O₂(g) → 2H₂O(l)

As we have the volume of hydrogen we need to work with denstiy to determine the moles that have reacted.

Density = mass / volume

Density . volume = mass → 0.071 g/L . 3.74L = 0.265 g

We determine the moles of H₂ → 0.265 g. 1mol/2g = 0.132 moles

In the reaction, ratio is 2:1. We make a rule of three:

2 moles of H₂ need 1 mol of O₂ to react

Then, 0.132 moles would need (0.132 .1)/2 = 0.066 moles of O₂

In order to determine the volume we need the oxygen's density but, we have to convert the mass to moles, firstly.

0.066 moles . 32 g/ 1mol = 2.12 g

Then oxygen's density = oxygen's mass / oxygen's volume

Oxygen's volume = oxygen's mass / oxygen's density

O₂ volume = 2.12 g / 1.43 g/L = 1.47 L

Answer 2

Answer:

1.87 L of O2 will react

Explanation:

Step 1: Data given

Volume of H2 = 3.74 L

Step 2: The balanced equation

2H2(g) + O2(g) →2H2O(l)

Step 3: Calculate moles H2

1 mol = 22.4 L

3.74 L = 0.167 moles

Step 4: Calculate moles O2

For 2moles H2 we need 1 mol O2 to produce 2 moles H2O

For 0.167 moles H2 we need 0.167/2 = 0.0835 moles O2

Step 5: Calculate volume O2

1 mol = 22.4 L

0.0835 moles = 22.4 * 0.0835 = 1.87 L

1.87 L of O2 will react