If the product side of a balanced chemical equation contains two water molecules, \(2\mathrm{H_2O}\), what total number of hydrogen atoms must be present on the reactant side?
Answer and explanation
Correct answer: Four
One \(\mathrm{H_2O}\) molecule contains 2 hydrogen atoms. Therefore, \(2\mathrm{H_2O}\) contains \(2 \times 2 = 4\) hydrogen atoms. In a balanced equation, the number of atoms of each element is the same on both sides, so the reactant side must also contain 4 hydrogen atoms. The option 2 applies to only one water molecule.
Frequently asked questions
What is the correct answer to this question?
Four
Why is this the correct answer?
One \(\mathrm{H_2O}\) molecule contains 2 hydrogen atoms. Therefore, \(2\mathrm{H_2O}\) contains \(2 \times 2 = 4\) hydrogen atoms. In a balanced equation, the number of atoms of each element is the same on both sides, so the reactant side must also contain 4 hydrogen atoms. The option 2 applies to only one water molecule.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Chemical Reactions and Equations.
