Question

The flame in a torch used to cut metal is produced by burning acetylene (C2H2) in pure oxygen. Assuming the combustion of 1 mole of acetylene releases 1251 kJ of heat, what mass of acetylene is needed to cut through a piece of steel if the process requires 20.7 × 104 kJ of heat?

Answer 1

Answer:

We need 4.31 kg of acetylene

Explanation:

Step 1: Data given

Combustion of 1 mol acetylene releases 1251 kJ of heat

Molar mass of acetylene = 26.04 g/mol

Step 2: Calculate moles of acetylene

1251kJ /mol * x moles = 20.7 * 10^4 kJ

x moles = 20.7 * 10^4 kJ / 1251 kJ/mol

x moles = 165.47 moles

Step 3: Calculate mass of acetylene

Mass acetylene = moles acetylene * molar mass acetylene

Mass acetylene = 165.47 moles * 26.04 g/mol

Mass acetylene = 4308.8 grams = 4.31 kg of acetylene

We need 4.31 kg of acetylene