4A + B2 →2A2B
The molar mass of A is 12 g/mol. The molar mass of B is 4 g/mol. The molar mass of A2B is 28 g/mol. When the goal of the reaction is to produce 112 g of the product, how many grams of reactant A should be present initially?
(1 point)
Responses
48
48
96
96
24
24
16
96
To calculate this, first determine the molar ratio between A and A2B in the balanced chemical equation. The coefficient of A is 4 and of A2B is 2, so the molar ratio is 4:2 or 2:1.
Next, calculate the number of moles of A2B needed to produce 112 g of the product:
Molar mass of A2B = 28 g/mol
Number of moles = 112 g / 28 g/mol = 4 moles
Since the molar ratio between A and A2B is 2:1, you need 2 moles of A to produce 1 mole of A2B.
Therefore, the number of moles of A needed is:
2 moles A * 4 moles A2B = 8 moles A
Finally, calculate the mass of A needed:
Molar mass of A = 12 g/mol
Mass of A needed = 8 moles * 12 g/mol = 96 g
Therefore, you should initially have 96 grams of reactant A present.