Hi there - My labs and lectures aren't in synch at the moment so we are now doing a prelab that is asking for info I haven't been taught yet uggg...
The prelab question I'm having trouble with is as follows:
What is the volume at STP for 0.415 g of argon gas? Also, what is the density of argon at STP?
my answer is probably completely wrong because I had no idea how to correctly work this out, but I did
molar volume of STP = volume of Argon/# of mol of Argon =0.415g/39.95mol = 0.01g/mol
Please when answering this question go step by step so I understand this completely.
Thanks...
0.415 g Ar = how many moles.
0.415/molar mass Ar = ??
Then 1 mole occupies 22.4L so ? moles will occupy .....L. You have calculated moles; convert that to volume at the rate of 22.4L for 1 mole.
Density of Ar = mass/volume and you can get that at STP 39.95/22.4 = ?g/L.
To solve this problem, we need to consider the concept of molar volume and ideal gas laws.
Step 1: Calculate the number of moles of argon gas.
In order to do this, we need to know the molar mass of argon. The molar mass of argon (Ar) is approximately 39.95 g/mol.
Number of moles (n) can be calculated using the formula:
n = mass (m) / molar mass (M)
Given that the mass of argon is 0.415 g:
n = 0.415 g / 39.95 g/mol ≈ 0.0104 mol (rounding to four decimal places)
Therefore, there are approximately 0.0104 moles of argon gas.
Step 2: Calculate the volume at STP (Standard Temperature and Pressure) using the ideal gas law.
At STP, the pressure (P) is 1 atmosphere (atm) and the temperature (T) is 273.15 Kelvin (K).
The ideal gas law can be written as:
PV = nRT
Where:
P = pressure
V = volume
n = number of moles
R = ideal gas constant (approximately 0.0821 L·atm/mol·K)
T = temperature in Kelvin
We can rearrange the formula to solve for volume:
V = nRT/P
Plugging in the known values:
V = (0.0104 mol)(0.0821 L·atm/mol·K)(273.15 K) / 1 atm
V ≈ 2.227 L (rounded to three decimal places)
Therefore, the volume of 0.415 g of argon gas at STP is approximately 2.227 L.
Step 3: Calculate the density of argon gas at STP.
Density is defined as mass per unit volume. In this case, we know the mass of argon is 0.415 g and the volume is 2.227 L.
Density (ρ) can be calculated using the formula:
ρ = mass (m) / volume (V)
ρ = 0.415 g / 2.227 L
ρ ≈ 0.186 g/L (rounded to three decimal places)
Therefore, the density of argon gas at STP is approximately 0.186 g/L.