Step-by-step explanation:
To solve this kind of problem we usually use the ideal gas law. The formula is:
P * V = n * R * T
Where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, T is the temperature. R is 0.082 atm*L/(mol*K), so we have to convert the temperature from °C to K and the pressure from mmHg to atm before solving the formula.
R = 0.082 atm*L/(mol*K)
V = 0.500 L
T(K) = T(°C) + 273.15 K
T(K) = 250 + 273.15 K
T(K) = 523.15 K
760 mmHg = 1 atm
P = 170 mmHg * 1 atm/(760 mmHg)
P = 0.224 atm
Now we can replace those values and solve the formula for the number of moles.
P * V = n * R * T
n = P * V/(R*T)
n = 0.224 atm * 0.500 L/(0.082 atm*L/(mol*K) * 523.15 K)
n = 0.00261 mol
Answer: There are 0.00261 mol in the sample.
If the temperature is 25 °C.
T = (273.15 + 25) K
T = 298.15 K
n = 0.224 atm * 0.500 L/(0.082 atm*L/(mol*K) * 298.15 K)
n = 0.00457 mol
Answer: There are 0.00457 mol in the sample.