Chemical Forums
Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: satha13 on March 29, 2014, 03:15:02 AM
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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?
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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?
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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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?
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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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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?
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First I find mass of Zn (38.1055 - 36.2142)
OK
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.