question archive 1) Automotive air bags inflate when sodium azide, NaN3, rapidly decomposes to its component elements upon ignition with an electrical spark
1) Automotive air bags inflate when sodium azide, NaN3, rapidly decomposes to its component elements upon ignition with an electrical spark
Subject:ChemistryPrice: Bought3
1) Automotive air bags inflate when sodium azide, NaN3, rapidly decomposes
to its component elements upon ignition with an electrical spark.
Hint: Remember to balance the equation!
NaN3 (s) ___________> Na(s) + N2 (g)
(a) How many moles are there in 10.0 g of NaN3?
____0.153___mol NaN3
10.0g x 1mol/65.0099 = 0.1538
(this is what I got but I'm not sure if it's right)
(b) How many grams of nitrogen gas (N2) can you produce from the amount of
NaN3 given in (a)?
_______ g N2
(c) A typical air bag is designed to contain 65 L of nitrogen gas (N2), which has a
density of 1.25 g/L. How many moles of nitrogen gas do you need to produce? Hint: Use the density formula to solve for grams (from the volume), and then find the number of moles from the molar mass of N2.
__________ moles N2
(d) Is the amount of NaN3 from (a) enough for a typical air bag, as in (c)? Explain your choice, briefly.
Yes No
2.)A piece of copper metal has a mass of 6.22 grams. Its specific heat is
0.385J/g oC. Calculate the amount of heat needed to take it from 20.5 oC to 324.3 oC.
[See p. 2, lecture notes, CH. 7] ________ J
2)The first step in the preparation of lead from its ore (galena, PbS) consists of "roasting" the ore in the following way:
____PbS (s) + ___ O2 (g) ______> ___SO2 (g) + ____PbO(s)
ΔHf (g/mol) (-98.32) (0) (-296.8) (-219.0)
(a) Balance the equation.
(b) Calculate the standard enthalpy change for this reaction, using enthalpies of formation (values are given below each substance) [See p. 7, lecture notes for an example (Ch. 7).]
_____________ kJ, ΔHf
