[stlramsfan1k]

Hey guys, here are a couple study guide questions for a quiz that I'm not 100% sure I'm right on. Just started this unit and want to see if my answers are good to go. Much appreciated.

Answers are bolded and are also at the bottom.

The nutritional label on a can of chicken noodle soup indicates that each serving contains 1.5 g fat, 8.0 g carbohydrates, and 3.0 g protein. How many total Calories are in a serving?

A) 58 Cal
B) 58 cal
C) None of the above

Which of the following reactions best illustrates an endothermic reaction?

A) Si(s) + 2 Cl2(g) → SiCl4(g) ΔH = -157 kcal
B) A chemical hot pack used as a hand warmer
C) Ca(OH)2 (s) + 65.3 kJ → CaO(s) + H2O(l)
D) Burning natural gas in a Bunsen burner

Which of the following would NOT affect the rate of a reaction?

A) heating the reaction
B) adding a catalyst
C) adding more reactants
D) using a beaker instead of a flask

Which of the following terms would be in the product(s) for the correctly balanced equation if the equilibrium expression is:
[CO2]2/[CO]2[O2]

A) CO2
B) O2
C) 2 CO
D) CO 2

Which of the following equilibrium constants would be the least enough of product formed in a reaction?

A) 8.9 X 10^14
B) 5.1 X 10^6
C) 1.3 X 10^-3
D) 9.4 X 10^-8

Which term in the following reaction would not be included in the equilibrium expression?
2 Na3PO4 (aq) + 3 MgCl2 (aq) → 2 Mg3(PO4)2 (s) + 6 NaCl (aq)

A) MgCl2
B) Mg3(PO4)2
C) Na3PO4
D) NaCl

What effect would be seen if additional nitrogen gas was added to the following reaction:
N2 (g) + 3 H2 (g) → 2 NH3 (g) + 22 kcal

A) The amount of energy given off will increase
B) the concentration of ammonia would decrease
C) the concentration of hydrogen gas would increase
D) The equilibrium would shift to the left

My Answer: We never actually went over this yet it's on the quiz... :\

Which of these statements is NOT true when a human is subjected to cold temperatures?

A) shivering cause the muscles to generate more heat
B) reactions in the body slow down
C) blood vessels dilate to help dissipate heat
D) blood vessels in the extremities constrict to reduce the loss of heat

In an exothermic reaction, which of the following would cause the reaction to shift to the right?

A) add product
B) raise the temperature
C) add reactant
D) add a catalyst

Answers:

B
A
C
C
A
A
?
C
C

[Dan]

Most of these are wrong. Can you explain your logic regarding your choices? That will make it easier to help you.

Anyway,

Answers:

B - Options A and B are the same
A - Wrong, a negative :delta: H means heat is released
C - Wrong, what determines the rate constant?
C - Wrong, K=[products]/[reactants]
A - Probably wrong, "the least enough of product" does not make sense though, so it's hard to tell. Does a bigger K value mean more or less product relative to reactants?
A  - Wrong
?  - Le Chatelier
C - Agreed
C - I think you're wrong, but I understand your logic. While adding more reagents will cause more products to be produced, it will not shift the position of equilibrium - the ratio of products to reactants (K) will be the same.

[sjb]

Most of these are wrong. Can you explain your logic regarding your choices? That will make it easier to help you.

Anyway,

Answers:

1) B - Options A and B are the same

Actually, I think that A and B are not the same here, a bit like mm and Mm are not the same amount of length. Cal (with an uppercase c) is 1000 cal (with a lowercase c) - http://en.wikipedia.org/w/index.php?title=Calorie&oldid=457494493. Looking around the kitchen, it seems that Cal (A) is probably the better answer.

[fledarmus]

C - I think you're wrong, but I understand your logic. While adding more reagents will cause more products to be produced, it will not shift the position of equilibrium - the ratio of products to reactants (K) will be the same.

[/quote]

The question is "which... will cause the reaction to shift to the right", which means forming more product. Adding more reagents will cause more products to form. C is the correct answer. A (adding more product) would shift the reaction to the left, and B and D (temperature and catalyst) won't change the equilibrium at all, just establish it faster.

[Dan]

Right you are, my mistake. Sorry stlramsfan1k.

[stlramsfan1k]

It's cool, no worries. Anyway. Here are the revised answers I came up with after doing some more research and reading. Here's what I came up with:


A
C
D
A
D
B
A
C
C

[Dan]

Looks good