The universal gas constant is 8.31451 J/K · mol. Calculate the change in internal energy of 7 mol of helium gas when its temperature is increased by 4.9 K. Answer in units of J.

Respuesta :

Answer:

Change in internal energy of the gas is given as

[tex]\Delta U = 427.8 J[/tex]

Explanation:

change in internal energy of the ideal gas is given as

[tex]\Delta U = \frac{f}{2}nR\Delta T[/tex]

here we know that

n = 7 mol

R = 8.31451 J/K-mol

[tex]\Delta T = 4.9 k[/tex]

since we know that Helium gas is a monoatomic gas so we have

[tex]f = 3 [/tex]

now we have

[tex]\Delta U = \frac{3}{2}(7)(8.31451)(4.9)[/tex]

[tex]\Delta U = 427.8 J[/tex]

The change in internal energy of 7 mol of helium gas will be "427.8 J". To understand the calculation, check below.

Helium gas

According to the question,

Moles of helium, n = 7 mol

Universal gas constant, R = 8.31451 J/K·mol

Temperature increased, ΔT = 4.9 k

Helium gas = Monoatomic gas, then

f = 3

We know the relation,

→ ΔU = [tex]\frac{f}{2}[/tex] nRΔT

By substituting the values, we get

        = [tex]\frac{3}{2}[/tex] × 7 × 8.31451 × 4.9

        = 427.8 J

Thus the answer above is right.

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