Question

The percent by mass is the ratio of the mass of each element to the total mass of the compound expressed as a percentage. Attached is the formula. What is the percent by mass of Oxygen in 10 grams of H20 given the mass by analysis of oxygen in that sample is 8 grams. (Answer should be given with a %. i.e. if the answer were 23% you answer in the textbox would be 23%)

Percent by mass = mass of solute mass of solution x 100 ​
help me please:((

Answer 1

The percent by mass of Oxygen : 80%

Further explanation

According to Proust: the mass percentage of the constituent elements of a compound is constant⇒compounds have a constant composition of elements

Given

mass of Oxygen (solute)= 8 grams

mass of H₂O(solution)=10 grams

Required

Percent by mass

Solution

$\tt percent~by~mass=\dfrac{mass~oxygen}{mass~solution}\times 100\\\\percent~by~mass=\dfrac{8}{10}\times 100=80$