Question

How much heat is needed to raise the temperature of 25 g of a substance by 15°C when the specific heat is .92 J/g-°C?

Answer 1

It will require `"350 J"` of heat energy to raise the temperature of the substance under the given conditions.

Explanation:

Use the following equation:

`q=cmDeltat,`

where:

`q` is heat energy, `c` is specific heat, `m` is mass, and `Deltat` is the change in temperature. `Deltat=T_"final"-T_"initial"`

Organize the data:

Known

`c=("0.92 J")/("g"*""^@"C")`

`m="25 g"`

`Deltat="15"^@"C"`

Unknown

`q`

Solution

Plug in the known values and solve for `q`.

`q=("0.92 J")/(color(red)cancel(color(black)("g"))*""^@color(red)cancel(color(black)("C")))xx25color(red)cancel(color(black)("g"))xx"15"^@color(red)cancel(color(black)("C"))="350 J"` (rounded to two significant figures)