a liquid has a mass of 18.39g. if 655j of heat are required to change the temperature from 32.8°c to 18.2°c…

Explanation:

Step1: Calculate temperature change

$\Delta T=T_{final}-T_{initial}=18.2^{\circ}C - 32.8^{\circ}C=- 14.6^{\circ}C$

Step2: Use heat - capacity formula

The formula for heat is $q = mc\Delta T$, where $q$ is heat, $m$ is mass, $c$ is specific heat capacity, and $\Delta T$ is temperature change. We can solve for $c$: $c=\frac{q}{m\Delta T}$. Substitute $q = 655J$, $m = 18.39g$ and $\Delta T=-14.6^{\circ}C$ into the formula. $c=\frac{655J}{18.39g\times(- 14.6^{\circ}C)}\approx - 2.44J/(g\cdot^{\circ}C)$ (the negative sign just indicates heat is released, we consider the magnitude). The specific - heat capacity of ethanol is approximately $2.44J/(g\cdot^{\circ}C)$.

Answer:

B. ethanol