- #1

- 90

- 9

- Homework Statement:
- How can I calculate diameter of a molecule

- Relevant Equations:
- none

How can I calculate diameter of a molecule

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- Thread starter new90
- Start date

- #1

- 90

- 9

- Homework Statement:
- How can I calculate diameter of a molecule

- Relevant Equations:
- none

How can I calculate diameter of a molecule

- #2

BvU

Science Advisor

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find a relationship between something with a known number of molecules and its volume

- #3

- 90

- 9

- #4

hutchphd

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perhaps you should state the entire problem rather than us playing "twenty questions".....?

- #5

- 90

- 9

ok,sorry...

- #6

- 90

- 9

- #7

BvU

Science Advisor

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So, what are you missing ?

- #8

- 90

- 9

the diameter of the molecule

- #9

BvU

Science Advisor

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How are you going to use this ?He assumed the molecules to be hard spheres tightly ppacked ina solid

- #10

DaveE

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Why do you think they gave you two density values, one for liquid, and one for gas?

- #11

- 90

- 9

i know because it it tighly packed the density of liquid and solid are very similar

- #12

DaveE

Science Advisor

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yes, so how can you use that information?

- #13

- 90

- 9

- #14

- 90

- 9

hello?

- #15

DaveE

Science Advisor

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Notice that the density given includes mass (g) in the dimensions, but mass doesn't appear anywhere else in the equations. This needs to be resolved somehow with external information.

Also note that there is a typo as presented you (or they) have mixed up the gas density and the liquid density in the problem. Easy to resolve though, use the larger one for liquids, the smaller one for gas.

- #16

DaveE

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A 1 cm x 1cm x 1cm cube of Aluminum has a density of 2.70 g/cm3. How many Al atoms are there in the cube? How far apart are they?

- #17

- 90

- 9

A 1 cm x 1cm x 1cm cube of Aluminum has a density of 2.70 g/cm3. How many Al atoms are there in the cube? How far apart are they?

what is the answer?

- #18

- 90

- 9

I dont know how to get the Al atoms

- #19

DaveE

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Then, when you find out how many atoms there are. How far apart are they (center to center, since they will be touching each other)? Imagine carefully placing tennis balls inside a big box to get as many as possible inside.

Finally, for the original problem, you will need to know that air is composed of 80% N

- #20

- 90

- 9

thnaks for the help we solve it

- #21

DaveE

Science Advisor

Gold Member

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Congratulations, good work!

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