2.25 I believe
Hope this helped!
STSN
Answer:

Explanation:
Hello,
In this case, since silver is initially hot as it cools down, the heat it loses is gained by the liquid, which can be thermodynamically represented by:

That in terms of the heat capacities, masses and temperature changes turns out:

Since no phase change is happening. Thus, solving for the heat capacity of the liquid we obtain:

Best regards.
1-It has to be 3 Fe and not Fe3.
2-The oxygens aren't balanced
Balanced equation:
3Fe+4H2O---->Fe3O4+4H2
D I have a good feeling about d
Electrons is located outside the nucleus