Homework Week 1 Question 6

[Jordyn Lee 1J]

If 8.32 g of CuNO3 is dissolved in water to make a 0.690 M solution, what is the volume of the solution in milliliters?

I tried using the formula MinitialVinitial=MfinalVfinal, but I am not sure how to find the molarity of the initial. I know the formula for molarity is n/V but I am still unsure how to solve this problem and whether I am using the correct formula to solve the problem.

[Chem_Mod]

In the case of this problem you are actually using a different equation to solve for the answer. You want to use the equation given by the definition of molarity which is molarity=mole/volume(L) there was a previous question on this if you need more clarification.

[Ethan Hung 2A]

The molar mass of CuNO₃ is 125.55g/mol, so you can solve for the number of moles. The number of moles (n) equals the molarity (M) multiplied by the volume (V). So, using n = MV, set the molarity (M) to the one given in the problem and plug in the number of moles you solved for earlier -- this will allow you to solve for the desired volume.

[AlexandriaHunt2J]

Hi! You're on the right track with using the formula Molarity = moles/volume in Liters. Because you are given the mass of the CuNO3 and the molarity of the CuNO3 in solution, after converting the mass of CuNO3 to moles, all you essentially need to do is plug in the values to calculate the volume of the solution, in mL.

[Matthew Vu 3C]

You should approach this problem using the equation given by the molarity definition rather than (M1)(V1)=(M2)(V2) because they only give you one concentration and one value for moles. You should find the moles of CuNO3 (gives grams of it in the problem so you need to convert), and then plug in your values to solve for volume. The molarity definition states that moles/volume = M. Now, you have moles and M, so work backwards to solve for volume

[Jayden Tan 2L]

Hello!!

For question six, I used the formula M = n/V, however, I began by finding the molar mass of the compound, which will give us grams per mole. Using grams per mole, you can then find the amount of moles within the solution by dividing 8.32g by its molar mass. Once you find the number of moles, you would plug everything into M = n/V and rearrange the equation until you end up with the volume. Hope this helps!!! You got this :))))

[Emily Widjaja 3A]

Hello!

You could start by calculating for the moles of CuNO3. then, you can use the formula concentration= moles/ volume to calculate the volume of the solution! Hope this helps :)

[Jiayin Yola Yan 1G]

You don't actually need to use the nintial=nfinal formula in this question. The question is asking you to find the volume needed for the solution, and the known values are the molarity of the solution and the grams (from which you can figure out the moles) of the solute. Therefore, just simply use the definition of molarity (mol/L) and change the sequence of variables then you can find the volume (in mL)!

[Angela_Li_1J]

For this question, you wouldn't need to use MinitialVinitial = MfinalVfinal, you just need to use the molarity equation M= n/V

You would start by converting the grams to moles by dividing by the molar mass of CuNO3, so 8.32 g/ 125.56 would give you 0.066 moles. Now, you can plug that value into the equation and solve for the volume.

0.69M = 0.066 moles / V
V= 0.096 L

Then you would convert liters to milliliters, giving you 96.03 mL

[celiaplaut3H]

I tried using the formula MinitialVinitial=MfinalVfinal, but I am not sure how to find the molarity of the initial. I know the formula for molarity is n/V but I am still unsure how to solve this problem and whether I am using the correct formula to solve the problem.[/quote]

I was also having an issue with this problem but the value for M of solution is 0.890. Is it like this for anyone else?

[madelyn kelly 1I]

To start off the problem, you first need to find the number of moles. # of moles = given mass of CuNO3/Molar Mass of CuNO3. We can find the molar mass of CuNO3 by adding up the atomic masses found on the periodic table. This would make the number of moles (n)= 8.32g/ 125.552g = 0.066 moles. From there, use the definition of molarity, M=N/V, to find the volume of the solution. Finally, convert L to mL. That value will be the volume of the solution in mL.

[madelyn kelly 1I]

I tried using the formula MinitialVinitial=MfinalVfinal, but I am not sure how to find the molarity of the initial. I know the formula for molarity is n/V but I am still unsure how to solve this problem and whether I am using the correct formula to solve the problem.

I was also having an issue with this problem but the value for M of solution is 0.890. Is it like this for anyone else?[/quote]

To start off the problem, you first need to find the number of moles. # of moles = given mass of CuNO3/Molar Mass of CuNO3. We can find the molar mass of CuNO3 by adding up the atomic masses found on the periodic table. This would make the number of moles (n)= 8.32g/ 125.552g = 0.066 moles. From there, we can then use the definition of molarity, M=N/V, to find the volume of the solution. Since you want to find the volume rather than the molarity, you could use the equation v= N/M [V= 0.066 (N) /.890 (M)= .074 L.] Finally, convert L to mL. That value will be the volume of the solution in mL. Hope this helps:)

[Heba Bounar 3K]

Hi!

For this problem, MiVi = MfVf is not necessary. Your first step would be to find the moles of CuNO3 by dividing the mass 8.32 g by its molar mass (125.557 gmol-1). With that value, you can use the formula M = n/V since you are given that the molarity is 0.690 M and you now know the moles of solute. From there, calculate the volume of the solution and convert to mL.

[Celine Khuu 2F]

For this question, all you need to do is convert the grams of CuNO3 into milliliters. To do so, you must remember that molarity (M), is just mol/L. Therefore, you convert g of CuNO3 to mol of CuNO3, then to L of CuNO3 (using the molarity that was given), and then finally to milliliters.

[Erin Chin 1L]

Hi! So first I would find the moles of CuNO3 using the given mass, 8.32 g. Use the formula M=n/V (Molarity, M, is the number of moles, n, per liter of solution, V) and basically plug in the values of n and M to find the V. Once you get a value for V, you need to convert to mL from L so multiply by 1000. Hope this helps you!

[Ruiyu Li 3I]

Hi! You could calculate the moles of CuNO3 by dividing the mass of CuNO3 by its molar mass, then you could use the equation V=n/M to calculate the volume. Hope this will help!

[masontsang]

Hi!

For this problem, I would use the equation: Molarity (M) = moles (n) / liters (L). Since you're given the grams of CuNO3, I would first convert the amount to moles. I calculated that 8.32g of CuNO3 is about 0.0663 mol CuNO3. Since we were also given the molarity of the solution, we can rearrange the equation to be liters (L) = moles (n) / Molarity (M). From there you can find the volume of the solution!

0.0663 mol CuNO3 / 0.690 M = 0.0960 L or 96.0 mL

I hope this helps!

[Isabella Perez Dis3L]

Hello! to solve this problem you would first find the molar mass of CuNO3. Then, you would need to find the moles of CuNO3 using the given mass. Next, you would use the formula you stated, M=n/V, and plug in the values of n and M to find the V. Lastly, once you get a value for V, you would need to convert mL from L. I hope this helps!

[Hailey Jeon]

Use the formula: molarity = (moles of solute)/(volume of solution)
Determine the molar mass of CuNO3 and then get the number of moles of it.
Substitute the value of molarity and moles of solute in the equation and solve for the volume. Then convert the value to mL.