# Question #1aff0

Apr 30, 2014

The thermochemistry base equation is $Q = m {C}_{p} T$ where
Q = Heat in Joules
m = mass of the material
* ${C}_{p}$ = specific heat capacity

T = change in Temperature ${T}_{f} - {T}_{i}$

• For this equation the metal is going to lose heat make Q negative while the water is going to gain heat making Q positive

Due to the Law of Conservation of Energy the heat lost by the metal will be equal to the heat gained by the water.

• $- {Q}_{C r} = + {Q}_{w a t e r}$

specific heat of water is 4.18 J/gC
specific heat of iron is 0.45 J/gC
We will assume that water boils at 100 C and that is the initial temp of the chromium.

$- \left[25.0 g \left({T}_{f} - 65.4 C\right) \left(0.45 \frac{J}{g} C\right)\right] = 100.0 g \left({T}_{f} - 20.0 C\right) \left(4.18 \frac{J}{g} C\right)$
$- 11.25 {T}_{f} + 735.75 = 418.0 {T}_{f} - 8360.0$
$9 , 095.75 = 429.25 {T}_{f}$
$21.19 C$