Answer :
Final answer:
The number of moles of hydrogen in a 38.6 ml sample at 26°C and 693 torr is calculated using the ideal gas law. After converting units to liters, Kelvin, and atm, the calculation yields approximately 0.00151 moles of hydrogen.
Explanation:
To calculate the number of moles of hydrogen in a 38.6 ml sample at 26°C and 693 torr, we can use the ideal gas law equation, PV = nRT, where P is pressure, V is volume, n is number of moles, R is the universal gas constant, and T is temperature in Kelvin.
First, we must convert the given volume to liters (L) by dividing 38.6 ml by 1000, which gives us 0.0386 L. Next, the temperature must be converted to Kelvin by adding 273.15 to the Celsius temperature, thus 26°C + 273.15 = 299.15 K. We also need to convert the pressure from torr to atm by dividing 693 torr by 760 torr/atm, yielding approximately 0.912 atm.
Next, we rearrange the ideal gas law to solve for n (number of moles): n = PV / RT. The gas constant R is 0.0821 L · atm/(K · mol). Substituting the values into the equation, we get:
n = (0.912 atm × 0.0386 L) / (0.0821 L · atm/(K · mol) × 299.15 K)
After calculating, we find the number of moles of hydrogen to be approximately 0.00151 mol.
