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Chem 534 Good News Monthly Question. Crystal Ball


p 60 Solutions

1. a.irreversible, assuming it won't rain in your dish.

b. equilibrium

c. steady state

d. irreversible

e. equilibrium

2. a. yes

b. no changes

c. If there is undissolved sugar at the bottom of the cup, the rate at which sugar molecules dissolve equals the rate at which they precipitate out of the coffee. If there is still a bit of room between the lid and the coffee, some liquid( water and nice-smelling compounds from coffee) molecules will be entering the gas phase. But for every molecule that does so, one will condense again and drip off the lid and fall back into the coffee.

3. No, even if you burned the log in a closed system, the products would not reunite to give you back the log. Combustion reactions are irreversible.

4. If the bottle is big enough, the drop may completely evaporate and, at a constant temperature, never condense again within the bottle.

5.a. yes

b. No! There may be a lot more reactants, or the opposite may be true. It all depends on the conditions under which the reaction is carried out ( temperature, pressure etc.) and on the nature of the reactants.

c. Yes, revealed by <-->

d. No, the rate is not revealed by the equation alone. You'd have to carry out an experiment.

e. Yes. They're all gases.

f. Yes. 156 kJ will be released.

g. No. We have no idea what the activated complex will look like from looking at the equation.

6. a. Irreversible: the conversion of amino acids into keratins, the proteins that make up your hair and nails.

the explosion of fireworks(any explosion, for that matter)


b. Steady state: the amount of water in your body.

the amount of CO2 in a pollution-free atomosphere

the number of students in a school experiencing no growth(graduates leave as new 7th graders enter)

the number of people in a city experiencing no growth (immigrants + births (input) = migrants + deaths(output)

c. Equilibrium: the humidity level in a closed bathroom some minutes after a shower.

chocolate-milk with excess chocolate liquid at the bottom of the glass