Question

Balance the following equation:
Cu+HgNO3 = Cu(NO3)2+Hg
Select the coefficient that would go in front of HgNO3.

Answer 1

To balance the chemical equation \( \text{Cu} + \text{HgNO}_3 \rightarrow \text{Cu(NO}_3)_2 + \text{Hg} \), we can follow these steps:

1. **List the number of atoms for each element on both sides of the equation**:
- Left side:
- Cu: 1
- Hg: 1
- N: 1
- O: 3
- Right side:
- Cu: 1
- Hg: 1
- N: 2 (from Cu(NO₃)₂)
- O: 6 (from Cu(NO₃)₂)

2. **Start balancing the equation**:
- We have 2 nitrogen (N) atoms and 6 oxygen (O) atoms on the right side from \( \text{Cu(NO}_3)_2 \). This means we need to adjust the coefficient in front of \( \text{HgNO}_3 \) to supply the necessary 2 nitrogen atoms and 6 oxygen atoms.

3. **Set the coefficient in front of \( \text{HgNO}_3 \)**:
- If we place a coefficient of 2 in front of \( \text{HgNO}_3 \), we will have:
- 2 HgNO₃ provides 2 nitrogen and 6 oxygen.
- The balanced equation will look like this:
\[
\text{Cu} + 2\text{HgNO}_3 \rightarrow \text{Cu(NO}_3)_2 + 2\text{Hg}
\]

4. **Re-count the atoms**:
- Now we have:
- Left side:
- Cu: 1
- Hg: 2
- N: 2
- O: 6
- Right side:
- Cu: 1
- Hg: 2
- N: 2
- O: 6

The equation is balanced. Therefore, the coefficient that should go in front of \( \text{HgNO}_3 \) is **2**.