The density of acetone vapor in equilibrium with liquid acetone, (CH3)2CO, at 33.1°C is 0.832 g L?1. What is the vapor pressure of acetone at 33.1°C, expressed in kilopascals?
agian i am confused with formulae, you can helpm thanks!
change 0.832 g to mols.
Use PV = nRT
P will be in KPa.
V = 1 L
n from your calculation.
R = 0.08205 when P is in atm and V in liters. But use 8.3145 if P is to be in kPa. Of course, you CAN calculate P in atmospheres, then convert to kPa knowing there are 1o1.325 kPa per 1 atm. I hope this helps.
thanks appreciate it!
You're welcome! I'm here to help. Let's go step by step to calculate the vapor pressure of acetone at 33.1°C in kilopascals.
First, we need to convert the given density of acetone vapor, which is 0.832 g/L, to moles.
To do this, we need the molar mass of acetone, which is (CH3)2CO. The molar mass of carbon (C) is 12.01 g/mol, the molar mass of hydrogen (H) is 1.01 g/mol, and the molar mass of oxygen (O) is 16.00 g/mol.
Adding up the molar masses of each element in acetone, we get:
(2 * 12.01 g/mol) + (6 * 1.01 g/mol) + 16.00 g/mol = 58.08 g/mol
Now, we can convert the given density of acetone vapor to moles. We know the density is 0.832 g/L, so for 1 L, the number of moles can be calculated as follows:
0.832 g/L / 58.08 g/mol = 0.01433 mol
Next, we can use the ideal gas equation, PV = nRT, where P is the vapor pressure we want to calculate, V is the volume (1 L in this case), n is the number of moles (0.01433 mol), R is the gas constant (which is 8.3145 J/(mol·K)), and T is the temperature in Kelvin.
To convert the temperature from degrees Celsius to Kelvin, we add 273.15:
33.1°C + 273.15 = 306.25 K
Now, we can rearrange the ideal gas equation to solve for P:
P = (n * R * T) / V
Plugging in the values we have:
P = (0.01433 mol * 8.3145 J/(mol·K) * 306.25 K) / 1 L
If you'd like the answer in kilopascals, we can convert the units by noting that 1 kPa is equal to 1000 Pa. So, we divide by 1000 to convert from Pascal to kilopascal:
P = (0.01433 mol * 8.3145 J/(mol·K) * 306.25 K) / 1 L / 1000 Pa
Calculating the expression gives us the vapor pressure of acetone at 33.1°C in kilopascals.