Question

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 759 mm Hg. If the wet C2H2 gas formed occupies a volume of 8.19 L, the number of moles of CaC2 reacted was ______ mol. The vapor pressure of water is 23.8 mm Hg at 25 °C.

Answer 1

To determine the number of moles of CaC2 reacted, use the ideal gas law equation PV = nRT. Convert the pressure to atm and temperature to Kelvin. Plug the values into the equation to find the number of moles.

Step-by-step explanation:

In order to determine the number of moles of CaC2 reacted, we need to use the ideal gas law equation, PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature in Kelvin.

First, we need to convert the pressure to atm by dividing 759 mm Hg by 760 mm Hg/atm, which gives us 0.9987 atm. We also need to convert the temperature from °C to Kelvin by adding 273.15 to 25 °C, which gives us 298.15 K.

Plugging the values into the equation, we have (0.9987 atm)(8.19 L) = n(0.08206 L·atm/mol·K)(298.15 K). Solving for n, we find that the number of moles of CaC2 reacted is approximately 0.347 mol.