hydrogen gas can be produced in the laboratory through the reaction of magnesium metal with hydrochloric acid: mg(s)+2hcl(aq)→mgcl2(aq)+h2(g) when 21.0g of mg reacts, what volume, in liters, of h2 gas is produced at 20∘c and 760 mmhg ?
Look at the balanced equation. for each mole of Mg consumed, two moles of H2 gas are produced. So the question is, how many moles of Mg was used: 21g/atomicmassMg
Now, twice that is the moles of H2 gas.
Volume?
V=nRT/P use the correct R for your units.
To determine the volume of hydrogen gas produced in this reaction, you will need to use the ideal gas law equation: 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 in Kelvin.
Step 1: Convert grams of magnesium (Mg) to moles.
The molar mass of magnesium (Mg) is 24.31 g/mol. To convert grams to moles, divide the given mass by the molar mass:
n(Mg) = mass(Mg)/molar mass(Mg)
n(Mg) = 21.0 g / 24.31 g/mol
Step 2: Determine the number of moles of hydrogen gas (H2) produced.
From the balanced chemical equation, we can see that 1 mole of magnesium reacts to produce 1 mole of hydrogen gas. Therefore, the number of moles of hydrogen gas produced is equal to the number of moles of magnesium:
n(H2) = n(Mg) = 21.0 g / 24.31 g/mol
Step 3: Convert moles of hydrogen gas to volume in liters.
We need to rearrange the ideal gas law equation to solve for V (volume):
V = n(H2) * R * T / P
- The gas constant, R, is equal to 0.0821 L·atm/(mol·K).
- The temperature, T, needs to be converted to Kelvin by adding 273.15 to the given temperature in °C.
- The pressure, P, is given as 760 mmHg, which needs to be converted to atm by dividing by 760 mmHg.
V = (n(H2) * R * T) / P
V = (21.0 g / 24.31 g/mol) * (0.0821 L·atm/(mol·K)) * (20°C + 273.15 K) / (760 mmHg / 760 mmHg/atm)
Step 4: Calculate the result.
Now, you can plug in the values into the equation and calculate the volume of hydrogen gas produced:
V = (21.0 g / 24.31 g/mol) * (0.0821 L·atm/(mol·K)) * (20°C + 273.15 K) / (760 mmHg / 760 mmHg/atm)
After performing the calculations, you will obtain the volume of hydrogen gas produced in liters.