Calculate Molarity of Co^2+ in a solution

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In summary, to calculate the molarity of the Co^2+ ion in each of the solutions 1-5, you will use the dilution factor formula (Dilution Factor = Starting Volume/Ending Volume) to find the new molarity of Co(NO3)2 in each solution. The original molarity of Co(NO3)2 is 0.160 and the dilution factors for solutions 1-5 are 0, 0.75, 0.5, 0.25, and 0.125 respectively. By multiplying the original molarity by the dilution factor, you can find the new molarity of Co^2+ in each solution.
  • #1
larry21
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Homework Statement


Calculate the molarity of the Co^2+ ion in each of the solutions 1-5. The new molarity is given by the molarity of the stock solution multiplied by the dilution factor.

Solution: Co(NO3)2

Original molarity: 0.160

Dilution #1: none
D#2: 12mL to 16mL
D#3: 8mL to 16mL
D#4: 4mL to 16mL
D#5: 2mL to 16mL

Please help I do not understand what I'm supposed to do. Thank you.
 
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  • #2
Co(NO3)2 --> (Co)+2 + 2(NO3)-1

Look at the coefficients. Your molarity of Co(NO3)2 will be the same as the Co+2 ions.

Dilution Factor = Starting Volume/Ending Volume

For #1, if you are not diluting the solution, you are not adding water. Your molarity will not change.

For #2, you are starting with 12 mL of 0.160M Co(NO3)2. Diluting to 16 mL will lower your molarity. Your dilution factor would be 12/16, or 0.75. Multiply this by the old molarity to get your new molarity.

Correct me if I'm wrong!
 
  • #3
Yes, that is what I thought as well, I just don't know what it meant by "Calculate the molarity of the Co^2+ ion in each of the solutions 1-5"

So the above statement just means to calculate the molarity of the Co(NO3)2 solution in each of the 5 diluted solutions?
 
  • #4
Does it help: you have a 1M (mole/L) solution of CaCl2. CaCl2 is completely dissociated. That means solution contains 1M of Ca2+ and 2M of Cl-.

Please note when asking homework type questions you should follow the template, otherwise you risk your question will be deleted. That's in forum rules.
 
  • #5
Try M1V1=M2V2 were m is your molarity and v is your volume. With the dilution factor you should be able to calculate your original and final volumes then plug them into get your other molarity.
 

Related to Calculate Molarity of Co^2+ in a solution

What is molarity?

Molarity is a unit of concentration that measures the number of moles of a solute dissolved in one liter of a solution. It is represented by the symbol M.

How do you calculate molarity?

Molarity is calculated by dividing the number of moles of the solute by the volume of the solution in liters. The formula is: M = moles of solute / liters of solution.

What is the formula for calculating molarity?

The formula for calculating molarity is: M = moles of solute / liters of solution.

What information do I need to calculate the molarity of Co^2+ in a solution?

To calculate the molarity of Co^2+ in a solution, you need to know the number of moles of Co^2+ present in the solution and the volume of the solution in liters.

Can molarity be used for any type of solution?

Molarity can be used for any type of solution as long as the concentration of the solute is known and the volume of the solution is measured in liters.

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