Question

Use the chemical reaction to answer the question.

2H2+O2→2H2O

There are four atoms of hydrogen (H
) before the reaction. How many atoms of hydrogen are present after the reaction?

(1 point)
Responses

2
2

4
4

5
5

8

Answers

GPT-4o mini
In the chemical reaction \(2H_2 + O_2 \rightarrow 2H_2O\), there are initially four hydrogen atoms (since \(2H_2\) means 2 molecules of \(H_2\), and each molecule contains 2 hydrogen atoms).

After the reaction, we produce \(2H_2O\) which also contains hydrogen atoms. Each water molecule (\(H_2O\)) contains 2 hydrogen atoms, and since we have 2 water molecules, we have:

\[
2 \text{ molecules of } H_2O \times 2 \text{ H atoms per } H_2O = 4 \text{ H atoms}
\]

Therefore, after the reaction, there are still 4 hydrogen atoms present.

The correct response is:

**4**