Question

A 5.5 gg sample of a substance contains only carbon and oxygen. Carbon makes up 35%% of the mass of the substance. The rest is made of oxygen. You are asked to determine the mass of oxygen in the sample. Which of the following expressions demonstrates a mathematical procedure to solve this problem using the proper order of operations?

a. ((100 - 35)/100) times 5.5 grams =
b. 100 - 35/100 times 5.5 grams =
c. 100 - (35/100) times 5.5 grams=

Answer 1

Answer:

a. ((100 - 35)/100) times 5.5 grams = 3.575 g

Explanation:

Given that:

The sample of carbon and oxygen = 5.5g

where carbon makes 35% of the mass of the substances.

It implies that oxygen will make: (100 - 35)% = 65%

Suppose y be the mass of the oxygen;

Then:

$y = \dfrac{(100-35)}{100} \times 5.5 \ g$

$y = \dfrac{(65)} {100} \times 5.5 \ g$

$y = 3.575 \ g$

The mass of carbon $= \dfrac{35}{100} \times 5.5 \ g$

= 1.925 g