Question

In the equation ___Na + ___H2O → ___NaOH + ___H2, how many Na atoms are on the left side of the equation after balancing?(1 point)
1
2
3
4

Answer 1

To balance the equation \( \_\_Na + \_\_H_2O \rightarrow \_\_NaOH + \_\_H_2 \), we need to ensure that the number of each type of atom is the same on both sides.

Starting with the unbalanced equation:

1. **Na** (sodium) on the left should balance with NaOH on the right.
2. **H** (hydrogen) in H2O combines to produce H2 and NaOH.
3. **O** (oxygen) in H2O is balanced with NaOH.

Let's balance the equation step by step:

- We have one NaOH for each Na, so we can start by putting a coefficient of 2 before Na, NaOH, and H2O. The equation will now look like this:

\[ 2Na + 2H_2O \rightarrow 2NaOH + H_2 \]

Now let's count the atoms:
- On the left side:
- Sodium (Na): 2
- Hydrogen (H): \(2 \times 2 = 4\)
- Oxygen (O): \(2 \times 1 = 2\)

- On the right side:
- Sodium (Na): 2
- From NaOH: \(2 \times 1 = 2\)
- Hydrogen (H): \(2 \text{ from } NaOH + 2 \text{ from H}_2 = 2 + 2 = 4\)
- Oxygen (O): \(2 \text{ from NaOH}\)

The equation is balanced now with:
- 2 Na on both sides.
- 4 H on both sides.
- 2 O on both sides.

Thus, the balanced equation is:

\[ 2Na + 2H_2O \rightarrow 2NaOH + H_2 \]

To answer your question, there are **2** Na atoms on the left side after balancing.