Question

Calculate the internal energy (in J) of 86 mg of helium at a temperature of 0°C.

Answer 1

The internal energy is 73.20 J.

Step-by-step explanation:

Given that,

Weight of helium = 86 mg

Temperature = 0°C

We need to calculate the internal energy

Using formula of internal energy

`U =nc_(v)T`

Where,
`c_(v)` = specific heat at constant volume

He is mono atomic.

So, The value of
`c_(v)= (3)/(2)R`

now, 1 mole of Helium = 4 g helium

n =number of mole of the 86 mg of helium

`n = (86*10^(-3))/(4)`

`n =2.15*10^(-2)\ mole`

T = 0°C=273 K

Put the value into the formula

`U = 2.15*10^(-2)*(3)/(2)*8.314*273`

`U = 73.20\ J`

Hence, The internal energy is 73.20 J.