A sample of hydrogen gas occupies 16.8 L at STP. How many moles of the gas are present?
Answer in units of mol
To find the number of moles of hydrogen gas present, we can use the Ideal Gas Law formula: PV = nRT, where P represents pressure, V represents volume, n represents the number of moles, R is the ideal gas constant, and T represents temperature.
At STP (Standard Temperature and Pressure), the pressure is 1 atmosphere (atm), and the temperature is 273.15 Kelvin (K). The ideal gas constant (R) is 0.0821 L·atm/(mol·K).
Given:
Volume (V) = 16.8 L
Pressure (P) = 1 atm
Temperature (T) = 273.15 K
Ideal gas constant (R) = 0.0821 L·atm/(mol·K)
We can rearrange the Ideal Gas Law formula to solve for n:
n = PV / RT
Substituting the given values:
n = (1 atm * 16.8 L) / (0.0821 L·atm/(mol·K) * 273.15 K)
Now, let's calculate it:
n = 16.8 / (0.0821 * 273.15)
n ≈ 0.627 mol
Therefore, there are approximately 0.627 moles of hydrogen gas present.