Question

Water consists of hydrogen and oxygen, and the approximate ratio, by mass, of hydrogen to oxygen is $2:16$. Approximately how many grams of oxygen are there in $144$ grams of water?

• A. $16$
• B. $72$
• C. $112$
• D. $128$
• E. $142$

Answer 1

Answer: (D)

$128$

Mass of hydrogen : Mass of oxygen = $2:16$

Sum of ratio = $2+16=18$

Total weight of water = $144gm$

$\therefore$ Mass of oxygen in water = $\frac{16}{18}\times 144gm=128gm$