Homework 57
- Page ID
- 28971
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Q 9.40
Of the given compounds, tell which are strong electrolytes and which are non electrolytes:
A. HCl B. H2SO4 C. CH3OH D. CO2
solution
Strategy and hints:
- Strong electrolytes are compounds that completely break up into ions when they dissolve in water.
- nonelectrolytes are compounds that only break up into molecules when in water and do not form ions
- start by separating the compounds and identify the ionic ones
- next, use the characteristics of strong electrolytes and nonelectrolytes to determine what each compound should be classified as
A. H+ & Cl- --> strong electrolyte
B. molecular compound --> nonelectrolyte
C. H+ & SO42- --> strong electrolyte
D. molecular compound --> nonelectrolyte
Helpful resources:
Q10.50
Ethane has a change in enthalpy of 5500.2 kJ when 1.0 mol is combusted at 1.0 atm with a change of internal energy of 5512.4 kJ. Calculate the amount of work done during combustion.
solution
Strategy and hints:
- write out down the "givens" in the problem
- choose the correct equation to determine the answer with the information you are given
- make sure your signs are correct
ΔEsystem=q+w ΔH = ΔE +ΔPV w= -PΔV
so, ΔE=ΔH+w
w=ΔH-ΔE
ΔE= 5512.4 kJ
ΔH= 5500.2 kJ
w= 5500.2 kJ - 5512.4kJ = -12.2 kJ
Helpful resources: