How many molecules of gas are in the sample?
The correct answer is 5.76 x 10²¹ molecules.
Explanation
The problem states that a sample of carbon dioxide is contained in a 250.0 mL flask at 0.917 atm and 19.3 ∘C. To find the number of molecules of gas in the sample, we can use the ideal gas law equation PV = nRT.
Given data:
- Volume (V) = 250.0 mL = 0.25 L
- Pressure (P) = 0.917 atm
- Temperature (T) = 19.3 ∘C = 292.3 K
First, we need to calculate the number of moles of gas (n):
n = PV/RT
n = (0.917 atm x 0.25 L) / (0.082 L.atm/K.mol x 292.3 K)
n = 9.6 x 10⁻³ mol
Next, we know that 1 mol of any compound is equal to 6.022 x 10²³ molecules of the compound. Therefore, we can convert moles to molecules using this ratio:
9.6 x 10⁻³ mol x 6.022 x 10²³ molecules / 1 mol = 5.76 x 10²¹ molecules
So, there are 5.76 x 10²¹ molecules of gas in the sample.