Question

Which of the following chemical equations is an example of the conservation of matter?

1. N2 + 3H2 arrow NH3
2. 2Na + I2 arrow 2Nal
3. 2H2O arrow H2 + O2
4. 2KCIO3 arrow 2KCI + O2

Answer 1

The principle of conservation of matter states that matter cannot be created or destroyed in a chemical reaction. This means that the number of atoms of each element must be the same on both sides of the equation.

Let's analyze each equation:

1. **N2 + 3H2 → 2NH3**
- Left side: 2 nitrogen atoms (N2) + 6 hydrogen atoms (3H2) = 2 N + 6 H
- Right side: 2 nitrogen atoms (2NH3) + 6 hydrogen atoms (2NH3) = 2 N + 6 H
- The number of atoms of each element is the same on both sides. This equation demonstrates conservation of matter.

2. **2Na + I2 → 2NaI**
- Left side: 2 sodium atoms (Na) + 2 iodine atoms (I2) = 2 Na + 2 I
- Right side: 2 sodium atoms (2NaI) + 2 iodine atoms (2NaI) = 2 Na + 2 I
- The number of atoms of each element is the same on both sides. This equation also demonstrates conservation of matter.

3. **2H2O → H2 + O2**
- Left side: 4 hydrogen atoms (2H2O) + 2 oxygen atoms (2H2O) = 4 H + 2 O
- Right side: 2 hydrogen atoms (H2) + 2 oxygen atoms (O2) = 2 H + 2 O
- The number of atoms does not match: 4 H on the left and 2 H on the right, thus this equation does not demonstrate conservation of matter.

4. **2KClO3 → 2KCl + 3O2**
- Left side: 2 potassium atoms (2KClO3) + 2 chlorine atoms (2KClO3) + 6 oxygen atoms (2KClO3) = 2 K + 2 Cl + 6 O
- Right side: 2 potassium atoms (2KCl) + 2 chlorine atoms (2KCl) + 6 oxygen atoms (3O2) = 2 K + 2 Cl + 6 O
- The number of atoms of each element is the same on both sides. This equation also demonstrates conservation of matter.

Based on this analysis, equations **1, 2, and 4** are examples of the conservation of matter. Option **3** does not follow the conservation of matter principle.