10. Gasoline is used to fuel a 4000 pound car accelerating from 0-55 miles per h

Question

10. Gasoline is used to fuel a 4000 pound car accelerating from 0-55 miles per hour. How many g of C8H18 are needed? Assume perfect efficiency. (hints: 1 kg=2.20 pound, 1 mile=1.61 km, j=kg m^2/s^2; E=1/2 mv^2)

C8H18(l) + 25/2 O2(g)8 CO2(g)+ 9H2O(g) Hrxn=-5074.1kj

11. Chlorine gas has a density d=7.64g/L at temperature T=30°C. What is the pressure in atm?

12. 10 atm of Ne is heatd from 10°C to 120°C. What is the pressure?

13. When of gypsum (calcium sulfate dihydrate also known as sheetrock) is heated to 350°F, water is released as it is converted to anhydrite (calcium sulfate). Sheetrock resists burnin in this way. The water is given off as steam (gaseous water vapor). How many L of steam is released from 23,000g sheet of gypsum wall board at 1 atm and 350°F?

CaSO4 2H2)(s)CaSO4(s) + H2)(g)

14. A 5.0g cooking oil is combusted releasing energy to heat 1000g of water from 21.3°C to 66.3°C. How many nutrition calories (cal) are releasaed from the bread? (1 Cal =1000cal=4180 J)

Explanation / Answer

10)let the amount of gasoline be x.so,

energy change of the car=delta(Mv^2*0.5)

=0.5*1814.369*24.5872^2

=5.48421*10^5 J

let the amount of fuel be m grams.

Heat of combustion of C8H18=-5074.1 kJ/mol.

molar mass=114.23 g/mol

so,

(m/114.23)*(5074.1*10^3)=5.48421*10^5

or m=12.34 grams

11) using the ideal gas equaiton,

PV=nRT

or P*M=rho*R*T

or P*71=7.64*(1/12)*(273+30)

or P=2.717 atm

12)P/T=constant.So,

10/(273+10)=P/(273+120)

or P=13.8869 atm

13)moles of gypsum=23000/195.6

=117.587 moles

moles of water=2*117.587

Temperature=449.817 K

using the ideal gas law,

PV=nRT

or 1*V=2*117.587*(1/12)*449.817

or V=8815.44 L

14)amount of energy releases=1000*4.18*(66.3-21.3)

=188100 J

=45000 Cal

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