Question

what is the change in heat of 15.8 grams of argon when its temperature decreases from 789°c to 112°c?
the specific heat of argon is 0.521 j/g°c.
round your answer to the correct number of significant figures.
joules
complete the sentence.
this process is by the argon as it cools.

Explanation:

Step1: Calculate the temperature change

The formula for temperature change $\Delta T=T_{final}-T_{initial}$. Here, $T_{initial} = 789^{\circ}C$ and $T_{final}=112^{\circ}C$. So, $\Delta T=112 - 789=- 677^{\circ}C$

Step2: Use the heat - change formula

The formula for heat change is $q = mc\Delta T$, where $m = 15.8g$, $c=0.521J/g^{\circ}C$, and $\Delta T=-677^{\circ}C$.
Substitute the values into the formula: $q=(15.8g)\times(0.521J/g^{\circ}C)\times(- 677^{\circ}C)$

First, calculate $(15.8\times0.521)=8.2318$
Then, $q = 8.2318\times(-677)=-5573.9286J$

Rounding to three significant figures (since $15.8$ has three significant figures, $0.521$ has three significant figures, and $677$ has three significant figures), $q=-5570J$

For the sentence:
When a substance cools, heat is released. A negative heat change indicates an exothermic process.

Answer:

• 5570 joules

This process is exothermic because heat is released by the argon as it cools.