Recall the heat capacity equation:
q = mc∆T
We're given mass, specific heat capacity, as well as the change in temperature. All we need to do is plug the numbers into the variables and we'll have our answer!
Although this question doesn't try to trick you, more often than not questions regarding energy change will attempt to throw you off with specific heat capacity. It's extremely important to note the units of the specific heat capacity and ensure that the numbers you use are in those units. As an example, the specific heat capacity might be given to you in J/mol*K - in this case, you'd have to do some unit conversions with your given data in order to fit all the numbers. In this question, we're given the specific heat capacity in J/gºC, so we don't need to change anything since all of our data is already in these units.
Anyways, back to the actual question:
q = mc∆T
q = (8.50 * [tex]10^{2}[/tex]) * (0.900) * (94.6 - 22.8)
q = 54927 (J)
Remeber to include significant figures:
54927 = 5.49 * 10^4 (J)
The required energy is 5.49 * [tex]10^{4}[/tex] Joules, or 5.49 * [tex]10^{1}[/tex] kJ
Let me know if you need any of my work to be explained!
- Breezeツ
