The formula that relates the heat and the temperature change is:
![Q=mc\Delta T](https://img.qammunity.org/2023/formulas/chemistry/college/tupuhfh0q3hc4crb5u9q9y9dk499stq4dd.png)
Where Q is the heat, m is the mass, c is the specific heat and ΔT is the temperature change.
Since it absorbes heat, the sign of Q is positive, so:
![Q=5000j](https://img.qammunity.org/2023/formulas/chemistry/college/levcy6ifzeob2ca8zy1yd90gb6fl7kns9z.png)
And the change in temperature is:
![\Delta T=T_f-T_i=30\degree C-15.0\degree C=15\degree C](https://img.qammunity.org/2023/formulas/chemistry/college/wh5tj091ndeows3ee8a96k4k1vtmplvkhy.png)
So, solving the equation for m and substituting the values, we have:
![\begin{gathered} Q=mc\Delta T \\ mc\Delta T=Q \\ m=(Q)/(c\Delta T)=(5000j)/(2.03j/g\degree C\cdot15\degree C)=164.20\ldots.g\approx164g \end{gathered}](https://img.qammunity.org/2023/formulas/chemistry/college/rece9n1r609hftp2uh18sma7gtgikqc7v5.png)
So, the mass of the sample is approximately 164 g.