Answer:
273 g
Step-by-step explanation:
a) Balanced equation
We know we will need an equation with masses and molar masses, so let’s gather all the information in one place.
M_r: 64.10 18.02
CaC₂ + 2H₂O ⟶ Ca(OH)₂ + 2C₂H₂
m/g: 485
(b) Mass of H₂O
(i) Calculate the moles of CaC₂
n = 485 g CaC₂ × (1 mol CaC₂/64.10 g CaC₂)
= 7.566 mol CaC₂
(ii) Calculate the moles of H₂O
The molar ratio is (2 mol H₂O /1 mol CaC₂)
n = 2.00 mol CaC₂ × (7.566 mol H₂O /1 mol CaC₂)
= 15.13 mol H₂O
(iii) Calculate the mass of H₂O
m = 165.16 mol H₂O × (18.02 g H₂O /1 mol H₂O)
= 273 g H₂O
The reaction requires 273 g H₂O.