Question

A 3.75 g sample of limestone, CaCO3, contains 1.80 g of oxygen and 0.450 g of carbon. What mass of calcium is present in the sample?

a. 1.00 g
b. 1.25 g
c. 1.50 g
d. 1.75 g
e. 2.00 g

Answer 1

Answer:

The mass of calcium in this sample is 1.50 grams (option c is correct)

Explanation:

Step 1: data given

Mass of CaCO3 = 1.80 grams

Molar mass CaCO3 = 100.09 g/mol

Mass of oxygen = 1.80 grams

Mass of carbon = 0.450 grams

Step 2: Calculate mass %

Mass % oxygen = (1.80 grams / 3.75 grams ) *100 %

Mass % oxygen = 48.0 %

Mass % carbon = (0.450 grams / 3.75 grams) * 100 %

Mass % carbon = 12.0 %

Step 3: Calculate mass % calcium

Mass % Ca = 100 % - 48.0 % - 12.0 %

Mass % Ca = 40.0 %

Step 4: Calculate mass Calcium

Mass Calcium = 3.75 grams * 0.40

Mass Calcium = 1.50 grams

The mass of calcium in this sample is 1.50 grams (option c is correct)