Calcium carbide, CaC2, can be produced in an electric furnace by strongly heating calcium oxide (lime) with carbon. The unbalanced equation is

CaO(s) + C(s) �¨ CaC2(s) + CO(g)
Calcium carbide is useful because it reacts readily with water to form the flammable gas acetylene, C2H2, which is used extensively in the welding industry. The unbalanced equation is
CaC2(s) + H2O(l) �¨ C2H2(g) + Ca(OH)2(s)
What mass of acetylene gas, C2H2, would be produced by complete reaction of 4.34 g of calcium carbide?

Here is a solved example of a stoichiometry problem. Just follow the steps.

http://www.jiskha.com/science/chemistry/stoichiometry.html

To find the mass of acetylene gas produced by the complete reaction of 4.34 g of calcium carbide, we need to use stoichiometry.

Step 1: Write balanced equations:
First, let's balance the given equations:

CaO(s) + C(s) → CaC2(s) + CO(g)

CaC2(s) + H2O(l) → C2H2(g) + Ca(OH)2(s)

Step 2: Determine the molar mass:
Next, calculate the molar mass of CaC2 and C2H2:

CaC2: Ca (40.1 g/mol) + C (12.0 g/mol) = 64.1 g/mol
C2H2: C (12.0 g/mol) + H (2.0 g/mol) x 2 = 26.0 g/mol

Step 3: Calculate the number of moles:
Now, we can determine the number of moles of CaC2:

moles CaC2 = mass / molar mass = 4.34 g / 64.1 g/mol ≈ 0.0677 mol

Step 4: Use stoichiometry to find moles of C2H2:
From the balanced equation, we can see that 1 mole of CaC2 produces 1 mole of C2H2. Therefore, the number of moles of C2H2 produced will be the same as the number of moles of CaC2:

moles C2H2 = 0.0677 mol

Step 5: Convert moles to mass:
Finally, we can find the mass of C2H2 produced:

mass C2H2 = moles × molar mass = 0.0677 mol × 26.0 g/mol ≈ 1.76 g

Therefore, approximately 1.76 g of acetylene gas (C2H2) would be produced by the complete reaction of 4.34 g of calcium carbide.