An unknown gas sample is collected in a 255mL container at 25 C and 755 mmHg. How many moles of gas are present?
show solution please so i can learn:D
You should use the same screen name. There is no learning, just plug into the formula. Don't forget T is in kelvin and P is in atmosphere if you use R = 0.08206
Use PV = nRT
.01035
To find the number of moles of gas present, we can use the Ideal Gas Law equation:
PV = nRT
Where:
P = pressure of the gas (in atm)
V = volume of the gas (in liters)
n = number of moles of gas
R = ideal gas constant (0.0821 L.atm/mol.K)
T = temperature of the gas (in Kelvin)
First, we need to convert the given values to the correct units. The pressure is given in mmHg, so we need to convert it to atm. There are 760 mmHg in 1 atm, so:
Pressure in atm = 755 mmHg / 760 mmHg/atm = 0.9934 atm
Next, we convert the volume from milliliters (mL) to liters (L). There are 1000 mL in 1 L, so:
Volume in L = 255 mL / 1000 mL/L = 0.255 L
The temperature is given in Celsius, so we need to convert it to Kelvin. To do this, we add 273.15 to the Celsius temperature:
Temperature in K = 25 C + 273.15 = 298.15 K
Now, we can substitute these values into the Ideal Gas Law equation:
(0.9934 atm) * (0.255 L) = n * (0.0821 L.atm/mol.K) * (298.15 K)
Simplifying the equation:
0.2536 = n * 24.449015
To isolate n, divide both sides of the equation by 24.449015:
n = 0.2536 / 24.449015
Calculating this:
n ≈ 0.0104 moles
Therefore, there are approximately 0.0104 moles of gas present in the 255 mL container at 25 °C and 755 mmHg.
To calculate the number of moles of gas present, we can use the ideal gas law equation:
PV = nRT
Where:
P is the pressure of the gas (in atm)
V is the volume of the gas (in liters)
n is the number of moles of gas
R is the ideal gas constant (0.0821 L·atm/(mol·K))
T is the temperature of the gas (in Kelvin)
First, let's convert the given values to the required units:
P = 755 mmHg (1 atm / 760 mmHg) ≈ 0.993 atm
V = 255 mL (1 L / 1000 mL) = 0.255 L
T = 25 °C + 273.15 = 298.15 K
Now we can substitute the values into the equation:
(0.993 atm) × (0.255 L) = n × (0.0821 L·atm/(mol·K)) × (298.15 K)
Simplifying this equation, we get:
0.253215 atm·L = 24.434015 n
n = 0.253215 atm·L / 24.434015
n ≈ 0.0104 moles
Therefore, there are approximately 0.0104 moles of gas present in the given container.