Calcium carbide reacts with water to produce acetylene gas according to the following equation: CaC2(s) + 2H2O(l)C2H2(g) + Ca(OH)2(aq) The product gas, C2H2, is collected over water at a temperature of 25 °C and a pressure of 749 mm Hg. If the wet C2H2 gas formed occupies a volume of 5.87 L, the number of moles of CaC2 reacted was mol. The vapor pressure of water is 23.8 mm Hg at 25 °C. Submit Answer

The number of moles of reacted was 0.229

Explanation:

According to ideal gas equation:

P = pressure of gas = Total pressure - vapor pressure of water = (749 - 23.8) mm Hg= 725.2 mm Hg = 0.954 atm    (760mmHg= 1atm)

V = Volume of gas = 5.87 L

n = number of moles = ?

R = gas constant =

T =temperature =

According to stoichiometry:

1 mole of is produced by = 1 mole of

Thus 0.229 moles of is produced by = moles of

Thus number of moles of reacted was 0.229

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.  

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