Question

Notice that "SO4" appears in two different places in this chemical equation. SO42− is a polyatomic ion called "sulfate." What number should be placed in front of CaSO4 to give the same total number of sulfate ions on each side of the equation?

Answer 1

Answer:

3.

Explanation:

Hello,

In this case, it is convenient to write the chemical reaction as:

$CaSO_4+AlCl_3\rightarrow CaCl_2+Al_2(SO_4)_3$

Which balanced turns out:

$3CaSO_4+2AlCl_3\rightarrow 3CaCl_2+Al_2(SO_4)_3$

Thus the number that should be in front of the calcium sulfate is 3 in order to balance the reaction.

Best regards.