When 9.44g of calcium is heated in air,13.22g of calcium oxide is formed.What is the percent by mass of calcium in this compound?
A)28.6%
B)40.0%
C)71.4%
D)13.2%

Question

Quizplus · Accepted Answer

To find the percent by mass of calcium in calcium oxide, we need to divide the mass of calcium in calcium oxide by the total mass of calcium oxide and then multiply by 100%.
The mass of calcium in calcium oxide is equal to the mass of calcium used to form calcium oxide, which is 9.44g.
The total mass of calcium oxide is 13.22g.
Percent by mass of calcium in calcium oxide = (9.44g/13.22g) x 100% = 71.4%
Therefore, the best choice is C, which corresponds to 71.4%.

When 944g of Calcium Is Heated in Air,13