Question

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

A. The enthalpy of the products is greater than that of the reactants.

B. The enthalpies of the reactants and the products are equal.

C. The enthalpy of the reactants is greater than that of the products.

**my answer: C

is that right? @aaronq :)

Answer 1

#2: In the diagram attached, which letter represents the transition from gas to liquid?

B, C, D or E?

**my answer: D

is that right?

Answer 2

#3: How much heat is needed to raise the temperature of 25 g of a substance by 15°C when the specific heat is 0.92 J/g-°C?

A. 65 J

B. 250 J

C. 345 J

D. 408 J

***my answer; C. 345 J

is this right? :)

Answer 3

#4: It takes 23.5 kJ of heat energy to raise the temperature of 100 g of a substance by 50°C. What is the substance?

*****REFER TO THE TABLE ATTACHED!!!! ***** :)

A. ammonia

B. water

C. ice

D. hydrogen

***my answer; A. ammonia

is that correct? :)

Answer 4

#5: According to the table attached, which gas would be most efficientthat is, have the greatest heat-storing abilityfor transferring heat from a heat source to a heat exchanger?

A. hydrogen

B. air

C. steam

D. oxygen

**my answer; A. hydrogen

is that right? :)

Answer 5

for #1, if enthalpy is negative, what does that mean?

Answer 6

that its exothermic? :/ not too sure if I'm remembering it right hahaa

Answer 7

haha damn, you're right on all. i thought the first was wrong at first, but it's not :P

Answer 8

lol omg!! yay :)

haha thanks!!! :D

Answer 9

no prob :)