Consider the following balanced chemical equation: 3(NH4)2CrO4 + 4Al + 24HCl --> 3CrCl2 + 6NH4Cl + 4AlCl3 + 12H2O.
a) How many moles of HCl would be required for the reaction of 0.0123 moles Al?
b) How many grams Al would be required for the reaction of 2.00g (NH4)2CrO4?
All work must be shown.
a).
mols HCl = mols Al x (24 mols HCl/4 mols Al) = mols Al x (24/4) = ?
B).
Convert grams (NH4)2CrO4 to mols. mols = grams/molar mass
Using the coefficients in the balanced equation (as I did above in part a)convert mols mols (NH4)2CrO4 to mols Al.
Now convert mols Al to grams. g = mols x atomic mass.
a) To determine the number of moles of HCl required for the reaction of 0.0123 moles of Al, we can use the balanced chemical equation. According to the equation, the stoichiometric ratio between Al and HCl is 4:24. This means that for every 4 moles of Al, we need 24 moles of HCl.
Given that we have 0.0123 moles of Al, we can set up a proportion to find the number of moles of HCl:
(0.0123 moles Al) / (4 moles Al) = (x moles HCl) / (24 moles HCl)
Cross-multiplying gives us:
0.0123 moles Al * 24 moles HCl = 4 moles Al * x moles HCl
0.2952 moles HCl = 4x
Dividing both sides by 4, we find:
x = 0.2952 moles HCl / 4 = 0.0738 moles HCl
Therefore, 0.0738 moles of HCl would be required for the reaction of 0.0123 moles of Al.
b) To determine the grams of Al required for the reaction of 2.00 grams of (NH4)2CrO4, we need to convert the given mass of (NH4)2CrO4 into moles, then use the stoichiometric ratio between Al and (NH4)2CrO4 to find the mass of Al.
Step 1: Calculate moles of (NH4)2CrO4 using its molecular weight.
The molecular weight of (NH4)2CrO4 can be determined by summing the atomic weights of its constituent elements:
(NH4)2CrO4 = 2(N) + 8(H) + Cr + 4(O)
The atomic weights are:
N = 14.01 g/mol
H = 1.008 g/mol
Cr = 52.00 g/mol
O = 16.00 g/mol
Therefore,
(NH4)2CrO4 = 2(14.01) + 8(1.008) + 52.00 + 4(16.00) = 152.08 g/mol
Now we can calculate the number of moles of (NH4)2CrO4:
moles (NH4)2CrO4 = mass (NH4)2CrO4 / molar mass (NH4)2CrO4
moles (NH4)2CrO4 = 2.00 g / 152.08 g/mol
Step 2: Use the stoichiometric ratio to determine the moles of Al.
According to the balanced chemical equation, the stoichiometric ratio between (NH4)2CrO4 and Al is 4:4. This means that for every 4 moles of (NH4)2CrO4, we need 4 moles of Al.
So, the moles of Al needed can be calculated as:
moles Al = moles (NH4)2CrO4
Step 3: Convert moles of Al to grams.
Now, using the molar mass of Al:
molar mass Al = 26.98 g/mol
mass Al = moles Al * molar mass Al
Substituting the known value:
mass Al = (2.00 g / 152.08 g/mol) * 26.98 g/mol
Calculating the above expression:
mass Al = 0.352 g
Therefore, 0.352 grams of Al would be required for the reaction of 2.00 grams of (NH4)2CrO4.