Assume that you have 2.75 g of the deadly gas hydrogen cyanide,HCN. What is the volume of the gas at STP?
How many moles do you have? That is moles = grams/molar mass.
Now, remember that one mole of any gas occupies 22.4 L. Calculate volume in liters.
To find the volume of the gas at STP, we need to use the Ideal Gas Law equation:
PV = nRT
Where:
P = pressure (at STP, pressure is 1 atm)
V = volume
n = number of moles of gas
R = ideal gas constant (0.0821 L·atm/mol·K)
T = temperature (at STP, temperature is 273.15 K)
First, we need to find the number of moles of hydrogen cyanide. To do that, we can use the molar mass of HCN, which is:
1 mole of H + 1 mole of C + 1 mole of N = 1 g + 12.01 g + 14.01 g = 27.02 g/mol
Now, we can calculate the number of moles by dividing the given mass (2.75 g) by the molar mass (27.02 g/mol):
number of moles = mass / molar mass
number of moles = 2.75 g / 27.02 g/mol
≈ 0.1016 mol
Now, we can substitute the values into the Ideal Gas Law equation:
PV = nRT
(1 atm) * V = (0.1016 mol) * (0.0821 L·atm/mol·K) * (273.15 K)
Simplifying the equation:
V = (0.1016 mol * 0.0821 L·atm/mol·K * 273.15 K) / (1 atm)
V ≈ 2.21 L
Therefore, the volume of the gas at STP is approximately 2.21 liters.
To find the volume of a gas at STP (Standard Temperature and Pressure), you will need to use the Ideal Gas Law equation, which is as follows:
PV = nRT
Where:
P = pressure (in atm)
V = volume (in liters)
n = number of moles
R = ideal gas constant (0.0821 L·atm/mol·K)
T = temperature (in Kelvin)
To calculate the volume, you will need to determine the number of moles (n) of HCN gas. To do this, you'll need to know the molar mass of HCN, which is found using the periodic table.
Molar mass of H = 1 g/mol
Molar mass of C = 12 g/mol
Molar mass of N = 14 g/mol
Therefore, the molar mass of HCN is:
(1 g/mol for H) + (12 g/mol for C) + (14 g/mol for N) = 27 g/mol
To calculate the number of moles (n), divide the given mass (2.75 g) by the molar mass of HCN:
n = 2.75 g / 27 g/mol
Next, convert the temperature to Kelvin. Since STP is 0 degrees Celsius or 273 Kelvin.
Now you have all the information needed to calculate the volume (V). Rearrange the Ideal Gas Law equation to solve for V:
V = (nRT) / P
Plug in the values you have:
V = (n * R * T) / P
V = (2.75 g / 27 g/mol) * (0.0821 L·atm/mol·K) * (273 K) / 1 atm
Now, calculate:
V = (0.1019 mol) * (0.0821 L·atm/mol·K) * (273 K) / 1 atm
The units cancel and give the volume in liters:
V = 2.16 liters
Therefore, the volume of the gas at STP is approximately 2.16 liters.