Su J. answered • 06/29/22
Enthusiastic, Patient, and Encouraging Chemistry Tutor
This question is asking about a dilution. Originally there is a 8.96M solution and after diluting the solution the new molarity is 0.600M. The equation used to calculate dilution is M1V1=M2V2, where the M1, stands for the initial molarity, the V1, stands for the initial volume, and M2 and V2 are the final molarity and volume of the solution, respectively.
In the question, we are given:
M1= 8.96M
V2= 2.50L
M2= 0.600M
The question asks us to find the volume, in milliliters, of the initial solution needed to make this dilution:
V1= ? mL
We can start by rearranging the dilution equation to isolate for V1, since that is what we are asked about. To do this we will divide both sides by M1.
M1V1=M2V2
V1=M2V2/M1
Then, we can plug in the numbers we were given.
V1= (0.600M)(2.50L)/(8.96M)
= 0.167 L
(Always double check that the units are canceling out! In this case the molarity (M) cancels and leaves us with L. This makes sense because we are solving for volume and liters is a unit of volume).
The question specifically asked for the volume to be given in milliliters, so the last thing we need to do is convert our answer in L to mL. 1000 mL is equal to 1 L, so we can convert by multiplying our answer by 1000mL/1L.
0.167 L (1000mL / 1L) = 167 mL
When you finish a calculation, you always want to take a second and ask yourself if the answer makes sense! In this case, the solution is becoming less concentrated, so that means that we will expect that the volume of the concentrated solution will be less than the volume of the diluted solution. So, we expect that the volume will be less that 2.5L. Since we calculated that it is, we can conclude our answer is at least reasonable!
