How much oxygen is required to burn calcium in the amount of 0.1 mol.

Given: N (Ca) = 0.1 mol
Find: N (O2) = x mol
Decision.
1. Let’s write the reaction equation: 2Ca + O2 = 2Cao
The coefficients in the equation show how many moles of the substance reacts.
According to the equation, 1 mole of O2 reacts with 2 moles of Ca.
2. We make up the proportion:
According to the equation – 1 mole of O2 reacts with 2 moles of Ca;
according to the condition – with 0.1 mol of Ca, x mol of O2 reacts.
Hence, 2 / 0.1 = 1 / x,
x = 0.1 * 1/2 = 0.05 mol
Answer: The amount of oxygen that is required to burn 0.1 mol of calcium is 0.05 mol.