A sample of 40.0 mL of hydrogen is collected by water displacement at a temperature of 20 degrees Celcius. The barometer reads 751 torr. What is the volume of the hydrogen at STP (standard temperature and pressure)?
To find the volume of hydrogen at STP (Standard Temperature and Pressure), we need to use the ideal gas law equation: PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature.
First, let's convert the temperature from Celsius to Kelvin by adding 273.15 to it.
So, the temperature in Kelvin = 20 degrees Celsius + 273.15 = 293.15 Kelvin
At STP, the pressure is 1 atmosphere (atm), which is equal to 760 torr. Therefore, we need to convert 751 torr to atm.
So, the pressure in atm = 751 torr / 760 torr/atm = 0.9882 atm (rounded to four decimal places)
Next, we can calculate the volume of hydrogen at STP. However, we don't have the number of moles of hydrogen, so we need to determine it first.
To find the number of moles, we can use the ideal gas law equation as follows:
n = PV / RT
Substituting the known values:
n = (0.9882 atm) * (40.0 mL) / [(0.0821 L*atm/mol*K) * (293.15 K)] (Note: The gas constant R is 0.0821 L*atm/mol*K)
Simplifying:
n = 0.0400 L*atm / (0.0821 L*atm/mol*K) = 0.4876 moles (rounded to four decimal places)
Now, using the number of moles, we can calculate the volume of hydrogen at STP.
Using the formula PV = nRT, we rearrange it to solve for V:
V = nRT / P
Substituting the known values:
V = (0.4876 moles) * (0.0821 L*atm/mol*K) * (273.15 K) / (1 atm)
Simplifying:
V = 10.21 L
Therefore, the volume of hydrogen at STP is 10.21 L (rounded to two decimal places).
To find the volume of hydrogen at STP (standard temperature and pressure), we need to convert the collected volume (at 20 degrees Celsius and 751 torr) to STP conditions.
STP conditions are defined as a temperature of 0 degrees Celsius (273.15 Kelvin) and a pressure of 1 atmosphere (760 torr).
To convert the volume of the hydrogen to STP, we can use the combined gas law, which states that the ratio of initial pressure, volume, and temperature to the final pressure, volume, and temperature remains constant, as long as the amount of gas and the number of moles remain the same.
The combined gas law formula is:
(P1 * V1) / T1 = (P2 * V2) / T2
Here's how we can use the formula to solve the problem:
1. Convert the temperature to Kelvin:
T1 = 20 degrees Celsius + 273.15 = 293.15 K
2. Gas law formula with given values:
(P1 * V1) / T1 = (P2 * V2) / T2
We can rearrange this formula to solve for V2 (the volume of hydrogen at STP):
V2 = (P2 * V1 * T1) / (P1 * T2)
Substituting the values into the formula:
P1 = 751 torr
V1 = 40.0 mL
T1 = 293.15 K
P2 = 760 torr (STP pressure)
T2 = 273.15 K (STP temperature)
V2 = (760 torr * 40.0 mL * 293.15 K) / (751 torr * 273.15 K)
Now we can calculate V2 by plugging in the values into the formula:
V2 = (29557600 torr * mL * K) / (20518065 torr * K)
= (29557600 / 20518065) * mL
≈ 1.44 * mL
Therefore, the volume of hydrogen at STP is approximately 1.44 mL.
Gug
Use(P1V1/T1) = (P2V2/T2)
For P1 substitute 751-vapor pressure H2O @ 20 C.
V1 = 40.0 mL
T1 = 273+20 = ? kelvin.
P2 and T2 are standard conditions. Solve for V2.
Note the correct spelling of celsius.