Formulae, mole ratios and equations

Question 1 of 10

Balance: C₃H₈ + O₂ → CO₂ + H₂O. The coefficient of O₂ is

Question 2 of 10

CH₄ + 2O₂ → CO₂ + 2H₂O. How many moles of oxygen are needed to burn 3 mol of methane completely?

Question 3 of 10

A hydrated salt CuSO₄·xH₂O loses 36% of its mass on heating. Find x (CuSO₄ = 160, H₂O = 18).

Question 4 of 10

In CH₄ + 2O₂ → CO₂ + 2H₂O, how many moles of water form from 3 moles of methane?

Question 5 of 10

The formula of aluminium sulphate is

Question 6 of 10

A compound has empirical formula CH₂ and relative molecular mass 56. Its molecular formula is

Question 7 of 10

In the balanced equation N₂ + 3H₂ → 2NH₃, how many moles of hydrogen react with 2 mol of nitrogen?

Question 8 of 10

Balance: Al + O₂ → Al₂O₃. The coefficients are

Question 9 of 10

What is the relative formula mass of calcium carbonate, CaCO₃? (Ca = 40, C = 12, O = 16)

Question 10 of 10

The empirical formula of C₆H₁₂O₆ is