Question

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

Answer 1

Answer:

The internal energy is 73.20 J.

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 $c_{v}= \dfrac{3}{2}R$

now, 1 mole of Helium = 4 g helium

n =number of mole of the 86 mg of helium

$n = \dfrac{86\times10^{-3}}{4}$

$n =2.15\times10^{-2}\ mole$

T = 0°C=273 K

Put the value into the formula

$U = 2.15\times10^{-2}\times\dfrac{3}{2}\times8.314\times273$

$U = 73.20\ J$

Hence, The internal energy is 73.20 J.