Question

Which balances the equation Mg + O2 → MgO?

Mg + 2O2 → 4MgO
2Mg + 2O2 → 2MgO
2Mg + O2 → 2MgO
2Mg + 2O2 → 4MgO

Answer 1

To balance the equation \( \text{Mg} + \text{O}_2 \rightarrow \text{MgO} \), we start with the unbalanced equation and count the number of each atom on both sides.

- On the left side:
- 1 Magnesium (Mg)
- 2 Oxygen (O) (from \( \text{O}_2 \))

- On the right side:
- 1 Magnesium (Mg)
- 1 Oxygen (O)

To balance oxygen, we need 2 oxygen atoms on the right side. This means we need 2 \( \text{MgO} \) on the product side. So we rewrite the equation as:

\[
\text{Mg} + \text{O}_2 \rightarrow 2\text{MgO}
\]

Now, on the right side, we have:

- 2 Magnesium (Mg)
- 2 Oxygen (O)

Thus, we need to also have 2 magnesium atoms on the left side. Therefore, we write:

\[
2\text{Mg} + \text{O}_2 \rightarrow 2\text{MgO}
\]

Now we have:

- Left Side: 2 Mg, 2 O
- Right Side: 2 Mg, 2 O

This equation is balanced.

So the correct answer is:

**2Mg + O2 → 2MgO**