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9. A sample of neon gas has a volume of 752 mL at 25.0 °C. What will the volume at 10.0 °C be if the pressure is constant?​

User ValYouW
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Answer & Explanation:

We can use the combined gas law to solve this problem:

(P₁V₁)/T₁ = (P₂V₂)/T₂

where P is pressure, V is volume, and T is temperature in Kelvin.

First, let's convert the temperatures to Kelvin:

T₁ = 25.0 °C + 273.15 = 298.15 K

T₂ = 10.0 °C + 273.15 = 283.15 K

Next, plug in the values we know:

(P₁)(752 mL)/(298.15 K) = (P₂)(V₂)/(283.15 K)

Since the pressure is constant, we can simplify the equation:

(P₁)(752 mL)/(298.15 K) = (P₂)(V₂)/(283.15 K)

(P₁)(752 mL)(283.15 K) = (P₂)(298.15 K)(V₂)

(P₁)(752 mL)(283.15 K)/(298.15 K) = P₂V₂

V₂ = (P₁)(752 mL)(283.15 K)/(P₂)(298.15 K)

We don't know the pressure, so we can't solve for V₂ directly. However, if we assume that the pressure stays the same, we can use the ideal gas law to find the pressure:

PV = nRT

where n is the number of moles of gas and R is the gas constant.

We know that neon is a monatomic gas with a molar mass of 20.18 g/mol. Let's assume we have one mole of neon gas:

PV = (1 mol)(8.314 J/(mol·K))(283.15 K)

P = (8.314 J/(mol·K))(283.15 K)/V

P = 2355 Pa

Now we can solve for V₂:

V₂ = (P₁)(752 mL)(283.15 K)/(P₂)(298.15 K)

V₂ = (1 atm)(752 mL)(283.15 K)/(2355 Pa)(298.15 K)

V₂ = 0.822 L or 822 mL (rounded to three significant figures)

Therefore, the volume of the neon gas at 10.0 °C and constant pressure should be approximately 822 mL.

User Srikar
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