given the reaction: 2 Al + 3 H2SO4 -> Al2(SO4)3 + 3 H2
what volume of H2 gas measured at STP will be produced from 5.4 grams of AL reacting with an excess of H2SO4?
To find the volume of H2 gas produced from the reaction, we need to use the concept of stoichiometry. Stoichiometry involves using balanced chemical equations to determine the ratios between reactants and products.
First, we need to determine the number of moles of aluminum (Al) present in 5.4 grams. To do this, we can use the molar mass of aluminum, which is 26.98 grams/mol.
Number of moles of Al = Mass (g) / Molar mass (g/mol)
Number of moles of Al = 5.4 g / 26.98 g/mol
Next, we need to determine the ratio between H2 and Al in the balanced equation. From the equation, we can see that the ratio of Al to H2 is 2:3. This means that for every 2 moles of Al, 3 moles of H2 are produced.
Using this ratio, we can calculate the number of moles of H2 produced:
Number of moles of H2 = Number of moles of Al * (3 moles of H2 / 2 moles of Al)
Now, to find the volume of H2 gas at standard temperature and pressure (STP), we use the ideal gas law equation: PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature.
At STP, the pressure (P) is 1 atmosphere and the temperature (T) is 273.15 K. The ideal gas constant (R) is 0.0821 L·atm/(mol·K).
Plugging in the values, we can solve for the volume (V):
V = nRT / P
V = (Number of moles of H2) * (R) * (T) / P
Substituting the appropriate values and calculating the volume will give us the answer.
To calculate the volume of H2 gas produced, we need to follow the steps below:
Step 1: Determine the molar mass of Al
The molar mass of Al can be found on the periodic table. It is approximately 26.98 grams/mol.
Step 2: Calculate the number of moles of Al
To calculate the number of moles, divide the given mass of Al (5.4 grams) by its molar mass (26.98 grams/mol).
Number of moles of Al = 5.4 grams / 26.98 grams/mol
Step 3: Use the balanced equation to determine the moles of H2 gas
According to the balanced equation, for every 2 moles of Al, 3 moles of H2 gas are produced. So, we can set up a proportion to determine the number of moles of H2 gas.
(2 moles Al / 3 moles H2) = (moles Al / moles H2)
Solving for moles H2:
moles H2 = (moles Al * 3 moles H2) / 2 moles Al
Step 4: Convert moles of H2 gas to volume at STP
1 mole of any gas at standard temperature and pressure (STP) occupies 22.4 liters. So, we can use this conversion factor to determine the volume of H2 gas produced.
Volume of H2 gas (in liters) = moles of H2 * 22.4 liters/mol
Let's calculate the values:
Step 1: Molar mass of Al = 26.98 grams/mol
Step 2: Number of moles of Al = 5.4 grams / 26.98 grams/mol = 0.2 moles
Step 3: Number of moles of H2 = (0.2 moles Al * 3 moles H2) / 2 moles Al = 0.3 moles H2
Step 4: Volume of H2 gas at STP = 0.3 moles H2 * 22.4 liters/mol = 6.72 liters
Therefore, approximately 6.72 liters of H2 gas will be produced.
This is a stoichiometry problem. Here is a solved example of a stoichiometry problem. Just follow the steps.
http://www.jiskha.com/science/chemistry/stoichiometry.html
After you have moles H2, use PV = nRT to convert moles to volume.