A 0.512g sample of CaCO3 is dissolved in 12M HCl and the mixture is diluted to 250ml. A. Calculate the concentration of Ca+2 in the 250ml solution?
B. How many moles of Ca+2 are in a 25ml sample of th 250ml solution?
To find the concentration of Ca+2 in the 250ml solution, we first need to find the number of moles of CaCO3 that were present in the sample. We can use the formula:
moles = mass / molar mass
The molar mass of CaCO3 is:
Ca: 40.08 g/mol
C: 12.01 g/mol
O: 16.00 g/mol (3 atoms)
Therefore, molar mass of CaCO3 = 40.08 + 12.01 + (16.00 x 3) = 100.09 g/mol.
So, moles of CaCO3 = 0.512 g / 100.09 g/mol = 0.00511 mol.
Since CaCO3 has a 1:1 ratio with Ca+2, the number of moles of Ca+2 is also 0.00511 mol.
Now, to calculate the concentration of Ca+2 in the 250ml solution, we can use the formula:
concentration = moles / volume
concentration = 0.00511 mol / 0.250 L = 0.0204 mol/L.
Therefore, the concentration of Ca+2 in the 250ml solution is 0.0204 mol/L or 20.4 mmol/L.
To find the number of moles of Ca+2 in a 25ml sample of the 250ml solution, we can use the formula:
moles = concentration x volume
moles = 0.0204 mol/L x 0.025 L = 0.00051 mol.
Therefore, there are 0.00051 moles of Ca+2 in a 25ml sample of the 250ml solution.
To answer these questions, we need to understand the process of calculating the concentration of a solution and the number of moles of a compound present in a given volume.
A. Calculate the concentration of Ca+2 in the 250ml solution:
First, let's convert the mass of CaCO3 given into moles. The molar mass of CaCO3 is as follows:
Ca: 40.08 g/mol
C: 12.01 g/mol
O: 16.00 g/mol (x3)
So the molar mass of CaCO3 = 40.08 + 12.01 + (16.00 x 3) = 100.09 g/mol
To calculate the number of moles:
moles of CaCO3 = mass of CaCO3 / molar mass of CaCO3
= 0.512 g / 100.09 g/mol
= 0.00511 mol (rounded to five significant figures)
Now we need to find the number of moles of Ca+2 ions produced when CaCO3 reacts with HCl. The balanced chemical equation is as follows:
CaCO3 + 2HCl → CaCl2 + H2O + CO2
From the equation, we can see that one mole of CaCO3 reacts with two moles of HCl to produce one mole of CaCl2. Therefore, the number of moles of Ca+2 ions is also equal to the number of moles of CaCl2.
Since the solution is diluted to 250 mL, we can use the equation:
Molarity (M) = moles / volume in liters
The volume in liters can be obtained by converting mL to L:
250 mL = 250 mL / 1000 mL/L = 0.250 L
Concentration of Ca+2 = moles of Ca+2 / volume of solution
= 0.00511 mol / 0.250 L
= 0.02044 M (rounded to five significant figures)
So, the concentration of Ca+2 in the 250 mL solution is approximately 0.02044 M.
B. How many moles of Ca+2 are in a 25 ml sample of the 250 ml solution:
We can use the same information from part A to calculate this.
We know the concentration of Ca+2 in the solution is 0.02044 M.
Using the formula:
moles = concentration x volume in liters
moles of Ca+2 = 0.02044 mol/L x (25 mL / 1000 mL/L)
= 0.000511 mol (rounded to six significant figures)
Therefore, there are approximately 0.000511 moles of Ca+2 in a 25 mL sample of the 250 mL solution.
1 mol CaCO3 contains 1 mol Ca^2+.
mols CaCO3 in 0.512 g = grams/molar mass = ?
M Ca^2+ = mols Ca^2+/L = ?
mols Ca^2+ in 25 mL is 1/10 mols in 250 mL.
Post your work if you get stuck.