Question

1) If 125 grams of ethene (C2H4) gas combusted, how many grams of oxygen would be used?

2) what mass(g) of zinc sulfate is produced from 25 g of solid zinc and excess sulfuric acid? this is a synthesis reaction, which produces zinc sulfate and hydrogen gas from solid since and sulfuric acid

Answer 1

For a balanced chemical equation, 2 moles of ethene (C2H4) will combine with 9 moles of oxygen (O2) to form 6 moles of carbon dioxide (CO2) and 8 moles of water (H2O). So, 125 grams of ethene will react with (9 moles of O2/2 moles of C2H4) * (32 g/mole O2) = 144 g of O2.

To calculate the mass of zinc sulfate (ZnSO4) produced, you need to balance the equation first:

Zn + H2SO4 → ZnSO4 + H2

So, for every 1 mole of zinc (Zn), 1 mole of zinc sulfate will be produced. 25 g of zinc will react with (25 g/65.38 g/mol) = 0.38 moles of Zn. Hence, the mass of zinc sulfate produced will be 0.38 moles * (161.5 g/mol) = 61.67 g.