How many grams of H2O are required to react with excess CaC2 to produce 23.0 g of C2H2 according to the following equation?
CaC2 + 2H2O -> Ca(OH)2 + C2H2
a.4.5
b.15.9
c.31.8
d.1.766
I think this equation works out by multiplying 2 moles by the molar mass of H2O. Please please help
To determine the grams of H2O required, we need to use stoichiometry.
We start by calculating the molar mass of C2H2 and H2O:
- Molar mass of C2H2: (2 * 12.01 g/mol) + (2 * 1.01 g/mol) = 26.04 g/mol
- Molar mass of H2O: (2 * 1.01 g/mol) + (16.00 g/mol) = 18.02 g/mol
Next, we calculate the moles of C2H2 produced using the given mass:
- Moles of C2H2 = mass of C2H2 / molar mass of C2H2 = 23.0 g / 26.04 g/mol ≈ 0.883 mol
According to the balanced equation, 1 mole of C2H2 is produced by reacting 2 moles of H2O. Therefore, the moles of H2O required can be found using the stoichiometry:
- Moles of H2O = (moles of C2H2) * (2 moles of H2O / 1 mole of C2H2) = 0.883 mol * (2 mol H2O / 1 mol C2H2) = 1.766 mol
Finally, we can convert moles of H2O to grams using the molar mass of H2O:
- Grams of H2O = (moles of H2O) * (molar mass of H2O) = 1.766 mol * 18.02 g/mol ≈ 31.8 g
Therefore, the grams of H2O required to produce 23.0 g of C2H2 is approximately 31.8 g.
The correct answer is c. 31.8.
To find the number of grams of H2O required to react, we first need to determine the molar mass of C2H2.
The molar mass of C2H2 is calculated by adding the atomic masses of the individual elements:
C: 2 atoms * atomic mass of carbon = 2 * 12.01 g/mol = 24.02 g/mol
H: 2 atoms * atomic mass of hydrogen = 2 * 1.01 g/mol = 2.02 g/mol
Total molar mass of C2H2 = 24.02 g/mol + 2.02 g/mol = 26.04 g/mol
According to the balanced chemical equation, 1 mole of CaC2 reacts with 2 moles of H2O to produce 1 mole of C2H2. Therefore, the molar ratio of H2O to C2H2 is 2:1.
To calculate the mass of H2O needed to produce 1 mole of C2H2, we can multiply the molar mass of H2O by the molar ratio:
Molar mass of H2O = 2 * atomic mass of hydrogen + atomic mass of oxygen = 2 * 1.01 g/mol + 16.00 g/mol = 18.02 g/mol
Mass of H2O needed = (18.02 g/mol) * (1 mole of C2H2 / 2 moles of H2O)
= 9.01 g
Finally, we can calculate the mass of H2O required to produce 23.0 g of C2H2:
Mass of H2O required = (9.01 g / 1 mole of C2H2) * (23.0 g of C2H2 / 26.04 g/mol)
= 7.96 g
Based on the calculations, the correct answer is not among the options provided. The closest option is d. 1.766 g, but this is not the exact value and may be a typo.
C2H2 is 26 g/mol (2*12 + 2*1)
so
23/26 mols
twice that many mols H20 at 18 g/mol
(46/26)18 = 31.8