Question

How much heat is required to raise the temperature from 26 degree centigrade to 50 degree centigrade for 100 gr lead?

Answer 1

`"400 J"`, or `"90 cal"`.

Explanation:

To solve this problem, we'll need to use this equation:

`q=mCDeltaT`

Where `q` is heat, `m` is mass in grams, `C` is specific heat, and `DeltaT` is change in temperature.

The question gives us `m`, which is `"100 g"`.
We can also use the initial and final temperatures given in the question, `"26°C"` and `"50°C"`, to find `DeltaT`. `DeltaT` is `50-26="24°C"`.

The specific heat of lead, from a quick search, is `"0.160 J/g°C"`.

So, we can just plug these into the equation and solve for `q`:

`q=mCDeltaT`
`q="100 g" xx "0.160 J/g°C" xx "24°C"`
`q="384 J"` or `"91.78 cal"`

Since the lowest number of significant figures in the question is `1`, our answer needs to also have `1` significant figure.
That would make it `"400 J"`, or `"90 cal"`.