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Topic: How to calculate Zn density with this experiment?  (Read 2216 times)

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Offline satha13

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How to calculate Zn density with this experiment?
« on: March 29, 2014, 03:15:02 AM »
Problem: To calculate Zn density as the following experiment

Empty flask weight is 36.2142 grams

Experiment 1: Pour water into Flask and weigh, total weight is 46.1894 grams


Experiment 2:
Step1: Put Zn powder into empty flask and weigh, total weight is 38.1055 grams
Step 2: Pour water into Flask that contained Zn powder and weigh, total weight is 47.8141 grams

What is Zn density?
Should I minus like this : 47.8141 - 46.1894 and Divide by Zn weight (38.1055 -36.2142)??

Can anyone guide me to solve this?
         

Offline Borek

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Re: How to calculate Zn density with this experiment?
« Reply #1 on: March 29, 2014, 05:10:55 AM »
Empty flask weight is 36.2142 grams

Experiment 1: Pour water into Flask and weigh, total weight is 46.1894 grams

How much water added? What was its volume?

Quote
Step1: Put Zn powder into empty flask and weigh, total weight is 38.1055 grams
Step 2: Pour water into Flask that contained Zn powder and weigh, total weight is 47.8141 grams

How much water this time? What was its volume?

Why is it different from the first volume?
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Offline satha13

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Re: How to calculate Zn density with this experiment?
« Reply #2 on: March 29, 2014, 09:22:47 PM »
From the first experiment: gram of water add equals 9.9752 (46.1894 - 36.2142), then volume of water is 9.9752 cm3

From the second experiment: I guess that gram of water equals 9.7068 (47.8141-38.1055), then water volume is 9.7086 cm3

But I am not sure about how to find Zn density from above data. Should I find the different between first volume and second volume?


Offline Borek

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Re: How to calculate Zn density with this experiment?
« Reply #3 on: March 30, 2014, 03:52:14 AM »
Should I find the different between first volume and second volume?

What will it yield? (I am not saying it is wrong: I am just trying to help you establish what is what).

Density is ratio of mass and volume - so you need to find both mass and volume of zinc.
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Offline satha13

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Re: How to calculate Zn density with this experiment?
« Reply #4 on: March 30, 2014, 06:04:46 AM »
Borek..I can solve this problem by your guiding

First I find mass of Zn (38.1055 - 36.2142)

Then I find the different of water volume from experiment 1 and 2. It equals 47.8141 - 46.1894 and it gives volume of Zn

Density of Zn is mass of Zn / volume of Zn

Is it correct?

Offline Borek

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Re: How to calculate Zn density with this experiment?
« Reply #5 on: March 30, 2014, 06:31:23 AM »
First I find mass of Zn (38.1055 - 36.2142)

OK

Quote
Then I find the different of water volume from experiment 1 and 2. It equals 47.8141 - 46.1894 and it gives volume of Zn

No, that's incorrect, as one of these masses contains also mass of zinc.

But you have already calculated both volumes of water earlier - now just find the difference between them.
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