# Question #bfecf

##### 1 Answer

#### Explanation:

For starters, let's figure out if the heat is *evolved*, which is a fancy term used to mean **given off**, or *absorbed*.

Notice that the temperature of the water **decreases** from **given off**.

Now, look at the **specific heat** of water, which is given to you as **increase** the temperature of *equivalent* to increasing the temperature by

Similarly, when the temperature of **decreases** by

You can thus say that the specific heat of water is

#"4.18 J g"^(-1)"K"^(-1) = "4.18 J g"^(-1)""^@"C"^(-1) = "4.18 J"/("1 g" * 1""^@"C")#

You can use the specific heat of water to calculate how much heat would be given off when the temperature of

#DeltaT = |76^@"C" - 89.9^@"C"| = 13.9^@"C"#

In this case, you would have

#13.9 color(red)(cancel(color(black)(""^@"C"))) * "4.18 J"/("1 g" * 1color(red)(cancel(color(black)(""^@"C")))) = "58.102 J g"^(-1)#

So, you know that when

#36.8 color(red)(cancel(color(black)("g"))) * "58.102 J"/(1color(red)(cancel(color(black)("g")))) = color(green)(bar(ul(|color(white)(a/a)color(black)("2140 J")color(white)(a/a)|)))#

I'll leave the answer rounded to three **sig figs**.