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# Calculating Mass and Moles

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GIVEN INFO:
from an unknown bottle:
Unknown= #25
Metal present= Na
Mass% metal= 43.88%

Atomic masses:
Cl= 35.453g
O= 16.0g
C= 12.0g
H= 1.00g

1. Mass of crucible and cover= 32.493g
2. Mass of crucible, cover, and unknown=33.001g
3. Mass of crucible, cover, and solid chloride= 33.017g
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Here is the information that I need to know (with significant figures).

1. mass of unknown
2. mass of solid chloride
3. Mass of metal in the unknown
4. number of moles of metal
5. Mass of Cl- in solid chloride
6. Moles of Cl- in solid chloride
7. Mole ratio in solid chloride (metal to chloride and not to the nearest integer)
8. Mole ratio in solid chloride (metal to chloride and to the nearest integer)
9. Formula of solid chloride
10. Mass of carbonate or hydrogen carbonate groups in unknown
11. Molar mass of group
12. Number of moles in unknown (IF it is a carbonate)
13. Molar mass of H group
14. Number of moles H in unknown (IF it is a hydrogen carbonate)
15. Mole ratio: [ Cl- in solid chloride to in unknown]
OR
[Cl- in solid chloride to H in unknown]
16. The mole ratio to the nearest integer from question 15
17. Formula of the unknown

https://brainmass.com/chemistry/physical-chemistry/calculating-mass-moles-132768

#### Solution Summary

The solution calculates the mass and moles given the atomic masses of different elements.

\$2.19

## Calculate mass, mole fraction and avg. molecular weight of air

Calculate the constituent (a) mass, (b) mole fraction (c)average molecular weight of air at 25 degree centigrade, 1 atm, and molar density of all listed gases is 24.5 L/mol, and volume air is given to be 100 L.

Name Volume fraction
N2 0.7808
O2 0.2095
Ar 0.0093
CO2 315 ppm
Ne 18 ppm
He 5.1 ppm
CH4 1.0 ppm
Kr 1.0 ppm

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