We are given the following information
Specific heat capacity of water = 4184 J/kg.°C
Amount of heat = 31,840 Joules
Change in Temperature = 22.0 °C to 28.5 °C
We are asked to find the mass of the water in grams.
Recall the specific heat capacity formula is given by
[tex]Q=m\cdot c\cdot\Delta T[/tex]Let us substitute the given values and solve for mass (m)
[tex]\begin{gathered} Q=m\cdot c\cdot\Delta T \\ 31,840=m\cdot4184\cdot(28.5-22.0) \\ 31,840=m\cdot4184\cdot6.5 \\ 31,840=m\cdot27,196 \\ m=\frac{31,840}{27,196} \\ m=1.1708\; kg \end{gathered}[/tex]Multiply the mass in kg by 1000 to convert into grams.
[tex]m=1.1708\times1000=1170.8\; g[/tex]Therefore, the mass of the water is 1170.8 grams.