Question

A substance of unknown mass absorbs 138 kilojoules of energy, going from 298 to 303 kelvin. if the specific heat of the substance is 7.11 j/g·°c, how much of the substance was present? 3.88 kg 32.3 g 3.88 g 32.3 kg

Answer 1

Heat absorbed to raise the temperature is given by

$Q = mc\Delta T$

here

m = mass

c = 7.11 J/g C

$\Delta T = 303 - 298 = 5 kelvin$

Q = 138 KJ

Now by using the above formula we will have

$138 * 10^3 = m* 7.11 * 5$

$m = 3881 gram$

$m = 3.88 kg$

So the amount of the substance will be 3.88 kg