Question

A balloon containing helium gas expands from 230
mL to 860 mL as more helium is added. What was
the initial quantity of helium present if the
expanded balloon contains 3.8 x 10-4 mol,
assuming constant temperature and pressure?
Which of the variables are known?

Answer 1

Answer:

1.0 *10^(-4) mol

Explanation:

For gases:

n1/n2 = V1/V2

n1/3.8*10^(-4) mol = 230 mL/ 860 mL

n1 = 3.8*10^(-4)*230/860 = 1.0 *10^(-4) mol

Answer 2

A balloon containing gas expands from 230 mL to 860 mL as more helium is added. 1.0 × 10⁻⁴ mole was the initial quantity of helium present if the expanded balloon contains 3.8 × 10⁻⁴ mole assuming constant temperature and pressure.

Ideal Gas Law

The ideal gas law states that the pressure of gas is directly proportional to the volume and temperature of the gas.

PV = nRT

where,

P = Pressure

V = Volume

n = number of moles  

R = Ideal gas constant

T = Temperature

Now, calculating the ratio between the initial and the final numbers of moles of gas

PV = nRT

or, $\frac{V}{n} = \frac{(RT)}{P}$

or, $\frac{V}{n} = k$

or, $\frac{V_1}{n_1} = \frac{V_2}{n_2}$

or, $\frac{n_1}{n_2} = \frac{V_1}{V_2}$        [Avogadro's Law]

Here, Volume and number of moles are the variables which are known.

Now put the values in above formula we get

⇒ $\frac{n_1}{n_2} = \frac{V_1}{V_2}$

⇒ $\frac{n_1}{3.8 \times 10^{-4}} = \frac{230}{860}$

⇒ $n_{1} = \frac{3.8 \times 10^{-4} \times 230}{860}$

⇒ n₁ = 1.0 × 10⁻⁴ mole

Thus, we can say that 1.0 × 10⁻⁴ mole was the initial quantity of helium present if the expanded balloon contains 3.8 × 10⁻⁴ mole assuming constant temperature and pressure. Volume and number of moles are the variables which are known.

Learn more about the Ideal Gas here: https://brainly.com/question/1063475

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