Answer:
0.0020 moles
Step-by-step explanation:
To calculate the number of moles, the Ideal Gas Law equation should be used:
PV = nRT
In this equation,
-----> P = pressure (atm)
-----> V = volume (L)
-----> n = number of moles
-----> R = Ideal Gas Constant (0.08206 L*atm/mol*K)
-----> T = temperature (K)
Before using the equation, you need to
(1) convert the pressure from mmHg to atm (760 mmHg = 1 atm)
(2) convert the volume from mL to L (1,000 mL = 1 L)
(3) plug the values into the equation and simplify to find "n"
P = 75 mmHg / 760 mmHg = 0.099 atm R = 0.08206 L*atm/mol*K
V = 500 mL / 1,000 mL = 0.5 L T = 300 K
n = ? moles
PV = nRT <----- Ideal Gas Law
(0.099 atm)(0.5 L) = n(0.08206 L*atm/mol*K)(300 K) <----- Insert values
0.0495 = n(24.618) <----- Multiply terms
0.0020 = n <----- Divide both sides by 24.618