Describe in detail the steps one would go through to make (in reality) 500mL of a 0.1M solution of cobalt(II) chloride from a container of powdered CoSO4.7H2O
You can't. There is no way you can weigh out CoSO4*7H2O and make it think it is CoCl2.
I was thinking maybe creating a chemical equation where a displacement reaction occurs... or maybe an equation with Cl ion being added?
2NaCl + CoSO4 --> Na2SO4 + CoCl2
Cl2 + CoSO4 --> CoCl2 + SO4
I just assumed you had made a typo. Apparently that is not the case. Let me think about it a couple of minutes and I'll get back to you.
What about adding BaCl2?
CoSO4.7H2O(aq) + BaCl2(aq) ==> CoCl2(aq) + BaSO4(s) + H2O
BaSO4 is a solid, it ppts (very insoluble), filter, wash thoroughly and all of the CoCl2 is in solution. Can you take it from here? As I see it, the CoSO4.7H2O can be weighed BEFORE starting the conversion, then collecting all of the CoCl2 and making to volume OR just take some CoSO4.7H2O, make the conversion, evaporate the CoCl2 soln to dryness, then weigh the correct amount of CoCl2 and go from there. I don't know the intent of the problem but as it's stated, I think you could go either way.
To make a 0.1M solution of cobalt(II) chloride from a container of powdered CoSO4·7H2O, here are the steps you would need to follow:
Step 1: Determine the molecular weight of CoSO4·7H2O
- Cobalt(II) sulfate heptahydrate (CoSO4·7H2O) has a molecular weight of approximately 281.1 g/mol.
Step 2: Calculate the mass of cobalt(II) sulfate needed
- To make a 0.1M solution, you need to know the number of moles required: 0.1 moles/Liter.
- Since you want to prepare a 500mL solution, the volume in liters is 0.5L.
- The number of moles required is then 0.1 moles/L * 0.5 L = 0.05 moles.
- The mass of cobalt(II) sulfate needed can be calculated using the molecular weight:
Mass = Moles * Molecular weight
Mass = 0.05 moles * 281.1 g/mol = 14.055 g
Step 3: Convert from cobalt(II) sulfate to cobalt(II) chloride
- Cobalt(II) sulphate heptahydrate (CoSO4·7H2O) contains cobalt as the cation.
- To convert this to cobalt(II) chloride, you need to consider the molar mass of cobalt(II) chloride and calculate the equivalent mass:
Cobalt(II) chloride (CoCl2) has a molecular weight of approximately 129.8 g/mol, which includes one Co2+ cation per formula unit.
Therefore, you can calculate the equivalent mass of CoSO4·7H2O using the ratio of molecular weights:
Equivalent mass of CoSO4·7H2O = Molecular weight of CoSO4·7H2O / Molecular weight of CoCl2
Equivalent mass = 281.1 g/mol / 129.8 g/mol = 2.166
Step 4: Calculate the mass of cobalt(II) chloride required
- Since the equivalent mass of CoSO4·7H2O is 2.166 g, and you need 0.05 moles (= 0.05 moles * 2.166 g/mole), the mass of cobalt(II) chloride to be added will be:
Mass = 0.05 moles * 2.166 g/mole = 0.1083 g
Step 5: Prepare the solution
- Weigh 0.1083 grams of CoSO4·7H2O and transfer it into a container.
- Add distilled water to the container to make a final volume of 500 mL.
- Stir the mixture until the CoSO4·7H2O is completely dissolved.
Congratulations! You have successfully prepared a 500 mL solution of 0.1M cobalt(II) chloride using the powdered CoSO4·7H2O.