A gas sample occupies a volume of 155 mL at a temperature of 316 K and a pressure of 0.989 atm. How many moles of gas are there?
(show your work)
since 1 mole occupies 22.4L at STP, we have
1*V/273 = 0.989*155/316
V = 132 mL
so you have 0.132/22.4 = 0.00591 moles
thx
To determine the number of moles of gas in a sample, we can use the ideal gas law equation: PV = nRT, where P is the pressure in atm, V is the volume in liters, n is the number of moles, R is the ideal gas constant (0.0821 L•atm/mol•K), and T is the temperature in Kelvin.
First, let's convert the volume from milliliters to liters:
155 mL = 155/1000 = 0.155 L
Next, plug the given values into the ideal gas law equation:
0.989 atm * 0.155 L = n * 0.0821 L•atm/(mol•K) * 316 K
Simplifying the equation:
0.152195 atm•L = n * 25.9576 L•atm/(mol•K)
To isolate the variable n, divide both sides by 25.9576 L•atm/(mol•K):
0.152195 atm•L / 25.9576 L•atm/(mol•K) = n
Calculating the result:
n ≈ 0.00586 mol
Therefore, there are approximately 0.00586 moles of gas in the sample.