Question

What is the percent by mass of oxygen in carbon dioxide (CO2)?
Use

%ELEMENT=TOTAL MASS OF ELEMENT IN COMPOUND/MOLAR MASS OF COMPOUND -X100

27.29%
57.12%
72.71%
79.99%

Answer 1

Answer:

= 72.73%

Explanation:

The percentage by mass of an element is given by;

% element = total mass of element in compounds/molar mass of compound × 100

The mass of oxygen in carbon dioxide = 32 g

Molar mass of CO2 = 44 g

Therefore;

% of O2 = 32/44 × 100%

             = 72.73%

Answer 2

Answer:

C

Explanation:

72.71%