D. Making the reactant particles larger
Answer:

Explanation:
Hello!
In this case, we can divide the problem in two steps:
1. Dilution to 278 mL: here, the initial concentration and volume are 1.20 M and 52.0 mL respectively, and a final volume of 278 mL, it means that the moles remain the same so we can write:

So we solve for C2:

2. Now, since 111 mL of water is added, we compute the final volume, V3:

So, the final concentration of the 139 mL portion is:

Best regards!
Answer:
Cannot be determined
Explanation:
Hi there,
Could you please add an attachment of the table? We cannot tell what the errors are if there is no table.
Sodium is very reactive but it’s a metal, and the problem asks specifically for a non-metal.
Silicone is technically reactive, but not super reactive.
Argon is a nonmetal, however it is an inert gas. It doesn’t react with anything.
We’re left with Chlorine, which is a non-metal in group 7, a highly reactive group, on the periodic table.
15. D is correct, exothermic reactions release heat
I am not sure about 16