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.
The problem is giving you 0.150M as the molarity and it tells you the new molarity will be the old one (0.160) x the dilution factor). After diluting, the first one will be 0.160 x (12mL/16mL)
The next one is 0.160 x (8 mL/16 mL).
However, from the way the problem is states I think it wants you to write the new molarity as the old molarity x the FACTOR. The dilution factor for the first one is (12/16) = 3/4; therefore, the first one will be
0.160 x (3/4), which of course is exactly the same answer as 0.160 x (12/16) but 3/4 is the dilution factor.
Okay, but what does it mean "Calculate the molarity of the Co^2+ ion in each of the solutions 1-5"
To calculate the molarity of the Co^2+ ion in each solution, you need to use the dilution formula. The dilution factor is the ratio of the final volume (after adding solvent) to the initial volume (stock solution).
In this case, the stock solution is Co(NO3)2 with an original molarity of 0.160. The dilution factor for each solution is given by the final volume divided by the initial volume.
Let's go step by step for each solution:
Solution 1: Dilution #1 (none)
Since there is no dilution, the dilution factor is 1.
Molarity = original molarity = 0.160 M
Solution 2: Dilution #2 (12mL to 16mL)
The dilution factor is 16 mL (final volume) divided by 12 mL (initial volume).
Dilution factor = 16 mL / 12 mL = 1.33
Molarity = original molarity * dilution factor = 0.160 M * 1.33 = 0.213 M
Solution 3: Dilution #3 (8mL to 16mL)
The dilution factor is 16 mL (final volume) divided by 8 mL (initial volume).
Dilution factor = 16 mL / 8 mL = 2
Molarity = original molarity * dilution factor = 0.160 M * 2 = 0.320 M
Solution 4: Dilution #4 (4mL to 16mL)
The dilution factor is 16 mL (final volume) divided by 4 mL (initial volume).
Dilution factor = 16 mL / 4 mL = 4
Molarity = original molarity * dilution factor = 0.160 M * 4 = 0.640 M
Solution 5: Dilution #5 (2mL to 16mL)
The dilution factor is 16 mL (final volume) divided by 2 mL (initial volume).
Dilution factor = 16 mL / 2 mL = 8
Molarity = original molarity * dilution factor = 0.160 M * 8 = 1.280 M
So, the molarity of the Co^2+ ion in each of the solutions is as follows:
Solution 1: 0.160 M
Solution 2: 0.213 M
Solution 3: 0.320 M
Solution 4: 0.640 M
Solution 5: 1.280 M