Answer:
D. 2
Explanation:
On the right side of the equation:
Al has 1, Zn has 3, NO3 has 6
But on the left side:
Al has 1, Zn has 1, NO3 has 3
1. So, if we add a coefficient of 2 to Al(NO3)3, then NO3 now has 6-which is what it needs.
2. But now the Al on the right side of the equation is not balanced, so give it a coefficient of 2.
3. To make the Zn balance, just add a coefficient of 3 on the left side of the equation.
Which leaves us with:
2Al + 3Zn(NO3)2 --> 2Al(NO3)3 + 3Zn
And now there are the same number of each compound on both sides of the equation.
Good luck! If you have any questions on this answer leave a comment :)
