Question

in the reaction ( 4al + _o_2 \to 2al_2o_3 ), what coefficient should be placed in front of the ( o_2 ) to balance the reaction?

( \bigcirc ) 1

( \bigcirc ) 2

( \bigcirc ) 3

( \bigcirc ) 4

Explanation:

Step1: Count oxygen atoms on the right - hand side

In \(2Al_2O_3\), the number of oxygen atoms is \(2\times3 = 6\)

Step2: Determine the coefficient of \(O_2\)

Let the coefficient of \(O_2\) be \(x\). Since each \(O_2\) molecule has 2 oxygen atoms, and the number of oxygen atoms on the left - hand side should equal that on the right - hand side. We have \(2x=6\), so \(x = 3\)

Answer:

3