Question

you decide to use aluminum \ice cubes\ to cool your juice. what is the heat change when 240. ml of juice is cooled from 21.0 °c to 6.0 °c?
$c_{juice} = 4.18 \\, \text{j/g}^\circ\text{c}$ $d_{juice} = 1.0 \\, \text{g/ml}$
$q_{juice} = ? \\, \text{j}$
+15 j +15,000 j
-15 j -15,000 j

Explanation:

Step1: Calculate mass of juice

Density formula: $m = d \times V$. Given $d = 1.0\ g/mL$, $V = 240\ mL$.
$m = 1.0\ g/mL \times 240\ mL = 240\ g$.

Step2: Calculate temperature change

$\Delta T = T_{final} - T_{initial} = 6.0^\circ C - 21.0^\circ C = -15.0^\circ C$.

Step3: Use heat formula $q = mc\Delta T$

$c = 4.18\ J/g^\circ C$, $m = 240\ g$, $\Delta T = -15.0^\circ C$.
$q = 240\ g \times 4.18\ J/g^\circ C \times (-15.0^\circ C)$
$q = 240 \times 4.18 \times (-15)$
$q = -15048\ J \approx -15,000\ J$ (rounded).

Answer:

-15,000 J