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Constructed Response . Topic 6: Moles and Stoichiometry

Set D: Molar mass from density calculation, mole calculation

Base your answers to questions 10 through 12 on the information below.

The decomposition of sodium azide, NaN3(s), is used to inflate airbags.

On impact, NaN3(s) is ignited by an electrical spark, producing N2(g) and Na.

The N2(g) inflates the airbag.

Write your answers here.

3
-4

10. An inflated airbag has a volume of 5.00 x 10 cm 10.

3
at STP. The density of N2(g) at STP is 0.00125g/cm .

What is the total number of grams of N2(g) in the bag?

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11. What is the total number of moles present in a 11.

52.0 gram sample of NaN3 .

(Grams-formula mass = 65.0 grams/mole)

12. Balance the equation to the right using the 12. ___ NaN3 -----> ___ Na + ___N2

smallest whole number coefficients.

Set E. Formula writing, formula mass calculation, moles calculation

Base your answers to questions 13 through 15 on the information below.

Sodium is essential ingredient in the human diet. The Federal Food and Drug

Administration recommends that the average adult daily requirement for

sodium is 2.4 grams. Sodium is ingested through consuming plants and animal

tissues, but another good source is table salt, sodium chloride.
Write and show work here.
13. What is the chemical formula for sodium chloride? 13.

14. What is the gram formula mass of a mole 14.

of sodium chloride?

15. Based on your answer to previous question (#14),

how many moles of table salt, sodium chloride 15.

would need to be consumed in order to ingest

the 2.4 grams ? [Show work]

Set F: Percent composition

Given the formula: NH4NO3

16. What is the percent composition by mass of 16.

Nitrogen in the formula ? (Show setup and answer)

17. What is the percent composition by mass of 17.

Oxygen in the formula ? (show set up and work)

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