Question

A sample of baking soda, naHCO3, always contains 27.37% by mass of sodium, 1.20% of hydrogen, 14.30% of carbon, and 57.14% of oxygen.

Which law do these data illustrate? State the law.

Answer 1

Answer: Law of definite proportion.

Step-by-step explanation: Law of definite proportion states that any chemical compound consists of elements in a fixed ratio by their masses. This law is also known as Proust's Law.

We are given a chemical compound
`NaHCO_3`

Assuming that the total mass of 1 mole of
`NaHCO_3` = 100 grams

where

Mass of Sodium = 27.37 grams

Mass of Hydrogen = 1.20 grams

Mass of Carbon = 14.30 grams

Mass of Oxygen = 57.14 grams

To Calculate the ratio of all the elements, we divide each of the masses by the lowest mass.

`\text{Mass ratio of Sodium}=(27.37)/(1.20)=22.80\approx 23`

`\text{Mass ratio of Hydrogen}=(1.20)/(1.20)=1`

`\text{Mass ratio of Carbon}=(14.30)/(1.20)=11.91\approx 12`

`\text{Mass ratio of Oxygen}=(57.14)/(1.20)=47.61\approx 48`

Mass ratio of elements in
`NaHCO_3=Sodium:Hydrogen:Carbon:Oxygen`

Na : H : C : O = 23 : 1 : 12 : 48

For every
`NaHCO_3` compound, this mass ratio will always be constant.