The flame in a torch used to cut metal is produced by burning acetylene (C2H2) in pure oxygen. Assuming the cumbustion of 1 mole of acetylene released 1251 kJ of energy, what mass of acetylene is needed to cut through a piece of steel if the process requires 5.42 x 10^4 kJ of energy?
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Calculate the moles, then grams.
? mole acetylene = 5.42x10^4 kJ x 1 mole C2H2 / 1251 kJ = 43.3 mole C2H2
? g C2H2 = 43.3 mole C2H2 x 26.0 g C2H2/mole C2H2 = 1130 g = 1.13 kg C2H2
? mole acetylene = 5.42x10^4 kJ x 1 mole C2H2 / 1251 kJ = 43.3 mole C2H2
? g C2H2 = 43.3 mole C2H2 x 26.0 g C2H2/mole C2H2 = 1130 g = 1.13 kg C2H2
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delta H (combustion) = 1251 kJ/mol
delta H2 =5,42*10^4 kJ
n(C2H2)=5,42*10^4 kJ/1251kJ/mol = 43,32 mol
m(C2H2)=n*M=43,32 mol * 26,036 g/mol =1128g=1,128 kg
delta H2 =5,42*10^4 kJ
n(C2H2)=5,42*10^4 kJ/1251kJ/mol = 43,32 mol
m(C2H2)=n*M=43,32 mol * 26,036 g/mol =1128g=1,128 kg