A sample of iron absorbs 81.0 J of heat, upon which the temperature of the sample increases from 17.9 °C to 32.5 °C.
If the specific heat of iron is 0.450 J/g-K, what is the mass (in grams) of the sample?

Mass = 12.33 g

Explanation:

The expression for the calculation of the enthalpy change of a process is shown below as:-

Where,  

 is the enthalpy change

m is the mass

C is the specific heat capacity

 is the temperature change

Thus, given that:-

Specific heat = 0.450 J/g°C

= 81.0 J

So,  

Mass = 12.33 g

the atomic number will stay the same no matter how many electrons it has, so it doesn’t decrease nor increase. it’ll only change with a different number of protons