# Serial dilution question

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#1
A student wanted to produce a dilution series of a maltose solution so he could plot a calibration curve. Had a stock solution of 0.6moldm-3 maltose and distilled water. Made dilutions from 0.1 to 0.6moldm-3.

volume of maltose = 5cm3
volume of water = 10cm3

what is the concentration of maltose solution?
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#2
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3 years ago
#3
(Original post by kiiten)
A student wanted to produce a dilution series of a maltose solution so he could plot a calibration curve. Had a stock solution of 0.6moldm-3 maltose and distilled water. Made dilutions from 0.1 to 0.6moldm-3.

volume of maltose = 5cm3
volume of water = 10cm3

what is the concentration of maltose solution?
I'm not amazig at dilutions but i will try; all the dilutions are of volume 15cm^3. Therefore if you think about it, a concentration of 0.6 moldom^-1 consists of 15 cm^3 of maltose and 0cm^3 of water. In the same way, if you therefore wanted a 0.3 moldm^-1 you would need half the amount of maltose so 7.5 cm^3 but therefore you also need 7.5 cm^3 of water. I have calculated this by doing 0.6/0.3 = 2 and therefore 15/2 = 7.5

Therefore you can work out the rest of the volumes for each solution in this way and the answer (if i'm not mistaken) is a concentration of 0.2 mold dm^-1
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#4
I'm not amazig at dilutions but i will try; all the dilutions are of volume 15cm^3. Therefore if you think about it, a concentration of 0.6 moldom^-1 consists of 15 cm^3 of maltose and 0cm^3 of water. In the same way, if you therefore wanted a 0.3 moldm^-1 you would need half the amount of maltose so 7.5 cm^3 but therefore you also need 7.5 cm^3 of water. I have calculated this by doing 0.6/0.3 = 2 and therefore 15/2 = 7.5

Therefore you can work out the rest of the volumes for each solution in this way and the answer (if i'm not mistaken) is a concentration of 0.2 mold dm^-1
Thank you!! Yeah, its correct.

You did better than my teachers, who didnt know how to solve it

So for a 0.6moldm^-3 solution you need 15cm^3 of maltose. In the example 5cm^3 of maltose is used. 15/5 = 3. So 0.6/3 = 0.2moldm^-3 solution. Is this how you worked it out?
1
3 years ago
#5
(Original post by kiiten)
Thank you!! Yeah, its correct.

You did better than my teachers, who didnt know how to solve it

So for a 0.6moldm^-3 solution you need 15cm^3 of maltose. In the example 5cm^3 of maltose is used. 15/5 = 3. So 0.6/3 = 0.2moldm^-3 solution. Is this how you worked it out?
Yes! You can work it out that way and its absolutely fine.
You could have also done 0.6/0.2 = 3 so 15/3 = 5 as an alternative but this is exactly the same method in reverse
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1 year ago
#6
How do you do diltuoion series - do you change amount of water or of dilute
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1 year ago
#7
(Original post by hannah300501)
How do you do diltuoion series - do you change amount of water or of dilute
both

concentration | volume of water /cm^3 | volume of 0.6 moldm^-3 maltose /cm^3
0.6 | 0 | 15
0.5 | 2.5 | 12.5
0.4 | 5 | 10
0.3 | 7.5 | 7.5
0.2 | 10 | 5
0.1 | 12.5 | 2.5

for the question:
volume of maltose = 5cm3
volume of water = 10cm3
concentration = 0.2 mol dm^-3
0
1 year ago
#8
(Original post by kiiten)
A student wanted to produce a dilution series of a maltose solution so he could plot a calibration curve. Had a stock solution of 0.6moldm-3 maltose and distilled water. Made dilutions from 0.1 to 0.6moldm-3.

volume of maltose = 5cm3
volume of water = 10cm3

what is the concentration of maltose solution?
Hi! I have that test today. I was wondering if you know where the question come from like which textbook or website.
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