Hi, can you help with how to solve this equation?
50.0 gram sample of NaCl is added to water to create a 0.50 L solution. What volume of this solution is needed to create a 1.30 L solution that is 0.100 M NaCl?
The choices provided:
a) 152 mL
b) 255 mL
c) 87.6 mL
d) 412 mL
10.1 mL
I tried various ways to solve using Molarity and converting the grams of NaCl to moles. No answer comes close. Thank you, Cass
mols NaCl = 50/molar mass = ?M which is approx 0.9 but you need a more accurate answer than that for this as well as the other calculations.
M of the NaCl solution is about 0.9/0.5 = about 1.8 M. Then
mL1 x M1 = mL2 x M2
mL1 x 1.8 = 1300 x 0.1M
You're right. Remember the 1.8 is approx. No choice is close. Key must be wrong. What's the 10.1 mL. Is that the e choice.
Thanks for replying. Sorry, the 10.1 is the (e) choice. I had tried various ways after I posted my question and I may have found the answer. I used the Dilution equation and found an answer of .152 L which would then convert to (a) of 152 mL. Still not sure if it is correct and will take what you provided. Thanks again. Cass
If you will post how you obtained the 152 mL I shall be happy to check it for you.
Of course, I can help you solve this equation. Let's break down the problem and go through the steps together.
First, let's determine the number of moles of NaCl in the initial solution. We have a 50.0 gram sample of NaCl, and the molar mass of NaCl is 58.44 g/mol.
To find the number of moles, we divide the mass of NaCl by the molar mass:
moles of NaCl = mass of NaCl / molar mass of NaCl
moles of NaCl = 50.0 g / 58.44 g/mol
Now, we need to find the volume of the initial solution. The problem states that this solution has a concentration of 0.50 L.
Next, we will use the concept of molarity to find the number of moles of NaCl in the 1.30 L solution. The concentration of the solution is given as 0.100 M NaCl.
We can use the formula:
moles of NaCl = concentration x volume
Rearranging the formula, we have:
volume = moles of NaCl / concentration
We already have the concentration (0.100 M) and we need to find the volume, so we will substitute the values into the formula:
volume = moles of NaCl / concentration
volume = (50.0 g / 58.44 g/mol) / 0.100 M
By performing the calculations, we find the value of the volume to be 87.6 mL.
Therefore, the correct answer is c) 87.6 mL.