Question

n an exothermic chemical reaction, the energy that is given off by the reaction comes from

A. the surroundings
B. an external heat source
C. stored energy in the chemical bonds of the reactants

Answer 1

c

Answer 2

i read it in a chem text book

Answer 3

haha thanks :)
Also would this one be C too?
In the chemical formula 2SO2, how many total atoms of oxygen (O) are there?

A. 2
B. 4
C. 6

Answer 4

i believe this one should be B

Answer 5

could you explain please? :)

Answer 6

wait are we saying that the 2 is a subscript

Answer 7

No we are just asking how many atoms of oxygen are there haha :)

Answer 8

well, oxygen is a diatomic molecule, so that means that there are 2 oxygen molecules, so there are 4 atoms of oxygen , so b

Answer 9

ohhhh I see.
thanks :)

Answer 10

wanna help on this one?
The bond enthalpy value for a carbon to hydrogen bond is 413 kJ. What does this mean?

A. It takes 413 kJ of energy to break a carbon to hydrogen bond.
B. The formation of a carbon to hydrogen bond releases 413 kJ of energy.
C. . Both of the above.

Answer 11

The bond enthalpy value tells us how much energy is needed for bond dissociation, so A looks like the right answer

Answer 12

hm.
okay :D

Answer 13

In the chemical formula 3NH4, how many total atoms of nitrogen (N) are there?

A. 1
B. 3
C. 12
C right?

Answer 14

basically what it takes to break up the bond

Answer 15

yea i figured :)

Answer 16

yeah looks like 12

Answer 17

but looks are deciving

Answer 18

after this one I only have 3 left ^_^ and this one would also be C right?
In the chemical formula 3NH4, how many total atoms of hydrogen (H) are there?

A. 1
B. 4
C. 12

Answer 19

there are actually only 3 total atoms of nitrogen in this compound

Answer 20

really?

Answer 21

mind explaining :)

Answer 22

well, the subscript on N is understood to be 1, and the 3 on the left get multiplied by that, so that we have 3 nitrogen atoms

Answer 23

ohhhh wow. looks ARE deceiving. thanks!

Answer 24

total atoms of H in that compound are , can you guess? 4

Answer 25

hahaha
okay

When balancing an equation you can

A. alter subscripts
B. change the identities of the products
C. change the identities of the reactants
D. write in coefficients
A right?

Answer 26

No, not A. All we can do is write in coefficients

Answer 27

hm.
i really need to study up on this subject >.<
Matter is _______ energy because matter is always ___________ in a chemical reaction.

A. different from; destroyed
B. similar to; conserved
C. similar to; created

B?

Answer 28

I am not quite sure, but i think it might be A, cause matter can be destroyed, but energy cannot

Answer 29

and also energy cannot be created in a chemical reaction

Answer 30

so C, is out

Answer 31

Oh, and B is also out, because in ALL chemical reactions, energy is lost, so it is not conserved

Answer 32

actually in the conservation of matter it states that matter can also not be destroyed or created?
which is weird.

Answer 33

matter, are you sure? i might be off lol

Answer 34

haha yea:
Law of Conservation of Matter:
Says that matter cannot be created or destroyed. Therefore, in a chemical reactionm no new atoms are created and none are destroyed. They are only re-arranged.
-This law demands that all atoms present in the reactants of a chemical reaction must be accounted for in the products. In other words, there must be the same number of each type of atom on the prouduct side and the reactant side. Making sure that this rule is obeyed is called balancing a chemical equation for a reaction. Go to the next page to learn more about balancing equations

Answer 35

hmmmm
i think i just found my answer..
HAHAHAHA
blondeness >:P

Answer 36

well, you might be right thats it B. I am not sure :)

Answer 37

okay :)

Answer 38

In the chemical formula 3NO2, the number “2” is a

A. subscript
B. place holder
C. element
last one!!

Answer 39

I thought you would have deduced the answer to this question already, well, its.............

Answer 40

A

Answer 41

haha
i am not really focused at all right now sorry.
i didn't even try >.<
I am doing several assignments at once to catch up.

Answer 42

been there :)

Answer 43

thanks :)