Question

calcuate the percentage composition of sodium in sodium hydroxide​

Answer 1

First, work out the relative formula mass of the compound, using the Ar values for each element. In the case of sodium hydroxide, these are Na = 23, O = 16, H = 1. (You will be given these numbers in the exam.) Next, divide the Ar of oxygen by the Mr of NaOH, and multiply by 100 to get a percentage.

Answer 2

Hi,

To find:

Percentage composition of Na in NaOH

Solution:

Relative formula mass of NaOH=23+16+1=40

Atomic mass of sodium=23

Percentage of sodium present in NaOH is given by  the formula

% of Na=Atomic mass of sodium/Relative formula mass of NaOH ×100

% of Na=23/40×100

% of Na=0.575×100=57.5%

hope this helps you