Question

#1: Which of the following is an exothermic reaction?

A. dissolving ammonium nitrate in water to cool the water

B. condensation

C. melting ice

D. dissolving sugar in water


**my answer; C

is that right? @aaronq :)

Answer 1

#2: Two objects (A and B) of the same temperature are in contact with each other. Which of the following statements is true?

A. Heat transfers from object B to object A, because molecules from B collide with those from A.

B. Heat transfers from object A to object B, because molecules from A collide with those from B.

C. Although the molecules collide, no heat transfers because there is no temperature difference between the objects.

D. No heat transfers, because there are no collisions between the molecules of the objects.

***My answer: C

is that right? not 100% sure :/

Answer 2

#3: Which of the following parameters is kept constant in a coffee-cup calorimeter?

A. temperature

B. volume

C. pressure

D. kinetic energy

***my answer: A. temperature

is that right? :)

Answer 3

hmm melting ice would be endothermic because it takes heat to map the process occur

Answer 4

#4: What type of substance would be best for use in a heating system?

A. a liquid with a high specific heat

B. a solid with a high specific heat

C. a liquid with a low specific heat

D. a gas with a low specific heat

***i think it's either A or B, but i'm not sure... what do you think? :)

Answer 5

2 is good

3 is not, in a calorimeter you measure the heat given off so the temperature will change

Answer 6

#5: The reaction 2 NO(g) → N2(g) + O2(g) has a ΔH = -180.5 kJ. How much heat will be required to produce 44.8 L of NO by the reverse reaction?

A. 644 kJ

B. 180.5 kJ

C. 301 kJ

D. 322.3 kJ

***my answer: B

is that right? :)

Answer 7

so would #1 be B? condensation? :/

and yay for 2!

and sooo i'm thinking #3 is B. volume then... is that right? :)

Answer 8

what do you think for those and 4 and 5 @aaronq :)

Answer 9

4 im not sure, i would say A because it will keep the heat longer across the pipes

Answer 10

1 would be condensation

3 i would say volume, but usually the pressure is not really changed, but yes say volume

Answer 11

okay :)

what about 5 then? :D

Answer 12

yeah, 180 :) i think.. because if you wrote it the other way, you would produce 2 times NO and 44 L is 2 moles so yes

Answer 13

awesome! :) Thanks!! :D

Answer 14

woooo no problem :)