Question

Suppose 20 atoms of hydrogen (H) react with chlorine (Cl) to produce 20 molecules of hydrochloric acid (HCl). According to the law of conservation of matter, how many atoms of chlorine reacted with the hydrogen?(1 point)
Responses

40
40

0
0

10
10

20

Answer 1

To determine how many atoms of chlorine reacted with the hydrogen to produce 20 molecules of hydrochloric acid (HCl), we can analyze the chemical reaction:

The balanced chemical equation for the formation of hydrochloric acid from hydrogen and chlorine is:

\[ \text{H}_2 + \text{Cl}_2 \rightarrow 2 \text{HCl} \]

From this equation, we can see that:

- 1 molecule of \( \text{Cl}_2 \) (which contains 2 chlorine atoms) reacts with 1 molecule of \( \text{H}_2 \) (which contains 2 hydrogen atoms) to produce 2 molecules of HCl.

Since you have 20 molecules of HCl produced, we can determine the number of chlorine atoms needed:

- Since 2 HCl molecules require 1 Cl2 molecule (which contains 2 Cl atoms),
- To produce 20 HCl molecules, you need 10 Cl2 molecules (since \( 20 / 2 = 10 \)),
- Therefore, 10 Cl2 molecules contain \( 10 \times 2 = 20 \) chlorine atoms.

Thus, the answer is that **20 atoms of chlorine** reacted with the hydrogen to produce the 20 molecules of hydrochloric acid.

**The correct response is: 20.**