Question

Question #f51b9

Answer 1

`"530 J"`

Explanation:

In order to be able to answer this question, you need to know the specific heat of silver.

`c_"Ag" = "0.240 J g"^(-1)""^@"C"^(-1)`

http://www2.ucdsb.on.ca/tiss/stretton/database/specific_heat_capacity_table.html

Now, the specific heat of silver tells you the amount of energy needed to increase the temperature of `"1 g"` of silver by `1^@"C"`.

You can thus say that if you add `"0.240 J"` of heat to `"1 g"` of silver, its temperature will increase by `1^@"C"`.

In your case, the temperature of the sample must increase by

`78^@"C" - 15^@"C" = 63^@"C"`

so use the specific heat to calculate the amount of heat needed to increase the temperature of a sample of silver by `63^@"C"`.

`63 color(red)(cancel(color(black)(""^@"C"))) * "0.240 J"/("1 g" * 1 color(red)(cancel(color(black)(""^@"C")))) = "15.12 J g"^(-1)`

This tells you that in order to increase the temperature of silver by `63^@"C"`, you must add `"15.12 J:"` of heat for every `"1 g"` of silver.

You can thus say that your sample will require

`35 color(red)(cancel(color(black)("g"))) * overbrace("15.12 J"/(1color(red)(cancel(color(black)("g")))))^(color(blue)("for a 63"""^@"C increase in temperature")) = color(darkgreen)(ul(color(black)("530 J")))`

The answer is rounded to two sig figs, the number of sig figs you have for your values.