Question

Acetylene gas (C2H2) is produced as a result of the reaction CaC2(s) + 2 H2O(ℓ) → C2H2(g) + Ca(OH)2(aq). If 10 g of CaC2 are consumed in this reaction, how much H2O is needed? Answer in units of mol.

Answer 1

`0.312` moles of water

Explanation:

We got the balanced equation:

`CaC_2(s)+2H_2O(l)->Ca(OH)_2(aq)+C_2H_2(g)uarr`

And so, one mole of calcium carbide will react with two moles of water. So, we need to convert `10 \ "g"` of calcium carbide to moles.

Calcium carbide has a molar mass of `64.1 \ "g/mol"`. So here, we need,

`(10color(red)cancelcolor(black)"g")/(64.1color(red)cancelcolor(black)"g""/mol")=0.156 \ "mol"`

Therefore, we would need,

`0.156color(red)cancelcolor(black)("mol of" \ CaC_2)*(2 \ "mol of" \ H_2O)/(1color(red)cancelcolor(black)("mol of" \ CaC_2))=0.312 \ "mol of" \ H_2O`