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Nonamiya [84]
3 years ago
11

A cylinder with a movable piston contains 2.00 g of helium, He, at room temperature. More helium was added to the cylinder and t

he volume was adjusted so that the gas pressure remained the same. How many grams of helium were added to the cylinder if the volume was changed from 2.00 L to 3.50 L ? (The temperature was held constant.)
Chemistry
1 answer:
mr Goodwill [35]3 years ago
8 0

Answer : The mass of helium added to the cylinder was, 1.5 grams

Explanation :

Avogadro's law : It is defined as the volume of gas is directly proportional to the number of moles of gas at constant pressure and temperature.

V\propto n

or,

\frac{V_1}{n_1}=\frac{V_2}{n_2}

where,

V_1 = initial volume of gas = 2.00 L

V_2 = final volume of gas = 3.50 L

n_1 = initial moles of gas = \frac{\text{Mass of He}}{\text{Molar mass of He}}=\frac{2.00g}{4g/mol}=0.5mol

n_2 = final temperature of gas = ?

Now put all the given values in the above equation, we get:

\frac{2.00L}{0.5mol}=\frac{3.50L}{n_2}

n_2=0.875mol

Now we have to calculate the mass of helium were added to the cylinder.

\text{Mass of He}=\text{Moles of He}\times \text{Molar mass of He}

\text{Mass of He}=0.875mol\times 4g/mol=3.5g

Mass of helium added = 3.5 - 2.00 = 1.5 g

Thus, the mass of helium added to the cylinder was, 1.5 grams

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