Question

MEDAL!!!!!!!! HELP PLEASE!

Answer 1

The following phase diagram shows how a catalyst affected the rate of a reaction.
http://prntscr.com/71w5fe

Which statement below best describes how the catalyst affected the reaction shown in this diagram?

The catalyst decreased the activation energy of the reactants.
The catalyst increased the activation energy of the reactants.
The catalyst increased activation energy of the products.
The catalyst decreased activation energy of the products.

Answer 2

@iGreen @AngelPSP

Answer 3

B

Answer 4

A sample of water is being heated over a flame. What happens to the water as it is heated?

The volume of the water decreases.
The water undergoes an endothermic reaction.
The kinetic energy of the water molecules increases.
The velocity of the water molecules begins to decrease.

Answer 5

I chose C

Answer 6

For the first problem, catalysts don't increase the activation energy.

Answer 7

Wait so it's A

Answer 8

Yes

Answer 9

Is the second one right?

Answer 10

Yep, good. :-)

Answer 11

I have a lot can you check?

Answer 12

You are welcome to post. I will check if I am able.

Answer 13

Okay thanks.

Answer 14

According to the collision theory, what two factors must be true for a collision to successfully result in a reaction?
sufficient kinetic energy and molar mass
correct orientation and sufficient energy
sufficient velocity and molecular mass
correct position and potential energy

I chose B

Answer 15

@JoannaBlackwelder

Answer 16

Yep

Answer 17

On a hot day, water vapor condenses on a cold glass. Which of the following best describes what happens during the condensation process?
increase in enthalpy in the system
decrease in entropy in the system
increase in kinetic energy
decrease in activation energy

I chose A?

Answer 18

The equation X + Y yields 2 Z has the rate law equation shown below. Which of the following statements best describes the relationship of Y on the rate of the reaction?

rate = k[X]2[Y]

Changing Y has no effect on the reaction rate.
Doubling Y causes the reaction rate to double.
Doubling Y causes the reaction rate to quadruple.
Dividing Y by two causes the reaction rate to double.

Also for this I chose C

Answer 19

Which statement about the following reaction is correct?

CaO (s) + H2O (l) yields Ca(OH) 2 (s) deltaH = -65.2 kJ

65.2 kJ of heat is absorbed for every one of CaO that reacts.
130 kJ of heat is released for every mole of H2O that reacts.
32.6 kJ of heat is released for every 0.5 mole of CaO that reacts.
16.3 kJ of heat is absorbed for every 0.5 moles of H2O that reacts.

And for this I chose A

Answer 20

@JoannaBlackwelder

Answer 21

Hold on, please hold off posting a new question until the first one is answered.

Answer 22

On a hot day, water vapor condenses on a cold glass. Which of the following best describes what happens during the condensation process?
increase in enthalpy in the system
decrease in entropy in the system
increase in kinetic energy
decrease in activation energy

I chose A?

I agree

Answer 23

The equation X + Y yields 2 Z has the rate law equation shown below. Which of the following statements best describes the relationship of Y on the rate of the reaction?

rate = k[X]2[Y]

Changing Y has no effect on the reaction rate.
Doubling Y causes the reaction rate to double.
Doubling Y causes the reaction rate to quadruple.
Dividing Y by two causes the reaction rate to double.

Also for this I chose C

I disagree

Answer 24

Why do you disagree?

Answer 25

Which statement about the following reaction is correct?

CaO (s) + H2O (l) yields Ca(OH) 2 (s) deltaH = -65.2 kJ

65.2 kJ of heat is absorbed for every one of CaO that reacts.
130 kJ of heat is released for every mole of H2O that reacts.
32.6 kJ of heat is released for every 0.5 mole of CaO that reacts.
16.3 kJ of heat is absorbed for every 0.5 moles of H2O that reacts.

And for this I chose A

I disagree

Answer 26

Because Y is to the first power.

Answer 27

So it would be A it has no affect?

Answer 28

Nope

Answer 29

Darn sorry Im not the best at this.

Answer 30

So im going to gues that the correct answer is B then.

Answer 31

No worries. :-) When a component has a power of one, when the concentration doubles, the rate also doubles.

Answer 32

Yep

Answer 33

Now for the third one....im confused.

Answer 34

Ok, when the enthalpy is negative, energy is released.

Answer 35

So that takes us to B or C

Answer 36

Would it be C?

Answer 37

Yep

Answer 38

Wow I didnt think I would get that!

Answer 39

Do you mind helping me with more?

Answer 40

Good job! :-)

Answer 41

Nope

Answer 42

Using the equations and enthalpy values provided, which mathematical expression can be used to determine the unknown enthalpy change of the decomposition of propane?

3 C + 3 O2 yields 3 CO2 deltaH =-1182 kJ
4 H2 + 2 O2 yields 4 H2O deltaH = -1144 kJ
C3H8 + 5 O2 yields 3 CO2 + 4 H2O deltaH = -2222 kJ
C3H8 yields 3 C + 4 H2 deltaH = ? kJ
These are the choices....
(-1182) - [(-2222) + (-1144)]
(-2222) - [(-1182) + (-1144)]
(-1182) +(-1144) + (-2222)
(-2222) + (-1182) - (-1144)

Answer 43

I dont even know where to start :(

Answer 44

We first need to try to add the top reactions to make the bottom reaction. Any ideas how to do that?

Answer 45

wouldnt it just be adding all of the kj?

Answer 46

Hm, not directly.

Answer 47

so -1182 + -1144 + -2222

Answer 48

No, that's not what I get.

Answer 49

We need the C and H2 to be the products, so we need to reverse those reactions.

Answer 50

So....you would have to have something like B?

Answer 51

Yep :-)

Answer 52

Can we please start a new question? This is getting ridiculously long.

Answer 53

An endothermic process is one in which heat is ________ from the surroundings.
gained
increased
lost
repelled

I chose A

Answer 54

Correct :-)

Answer 55

Which term below best matches a potential energy diagram in which the potential energy value of the reactants is less than that of the products?

activation energy
reaction pathway
exothermic process
endothermic process

I chose A but I dont think that it's right

Answer 56

@JoannaBlackwelder

Answer 57

I agree that it is not right.

Answer 58

Or is it exothermic?

Answer 59

No, that is when the reactants have more potential energy.

Answer 60

Reaction pathway...........i suck at chemistry :_(

Answer 61

Think about this one a min. When the reactants have less energy than the products, the reactants absorbed energy. What kind of reaction is that?

Answer 62

endothermic

Answer 63

:-) I knew you could do it!

Answer 64

Which of the following must be true about a reaction if it is only spontaneous at high temperatures?
It is exothermic, with both negative enthalpy and entropy changes.
It is endothermic, with both positive enthalpy and entropy changes.
It is exothermic, with a negative enthalpy and positive entropy change.
It is endothermic, with a positive enthalpy and negative entropy change.

I chose C
I do know it has to be exothermic

Answer 65

@JoannaBlackwelder

Answer 66

Hm, why do you think it would be exothermic?

Answer 67

http://chemwiki.ucdavis.edu/Physical_Chemistry/Thermodynamics/State_Functions/Free_Energy/Gibbs_Free_Energy/Gibbs_Free_Energy

Answer 68

Oh so that was wrong? Endothermic?

Answer 69

Yeah, it would be endothermic.

Answer 70

Spontaneous means negative delta G.

Answer 71

Ohhh okay that makes sense

Answer 72

:-) So, any ideas given that info?

Answer 73

B

Answer 74

Great!

Answer 75

Which statement below best describes the relationship of the reaction below?

3 A + B yields 2 AB

For every AB produced, the reaction requires three A.
The rate of formation of AB is twice the disappearance of A.
For every two AB produced, the reaction requires three A.
The rate of disappearance of A is two times the formation of AB.

I have no clue

Answer 76

@JoannaBlackwelder

Answer 77

We are looking at the molar ratios in the problem. What are the coefficients for A and AB?

Answer 78

3?

Answer 79

That is the coefficient of A. What about AB?

Answer 80

1?

Answer 81

Hm, I see a 2 in front of AB

Answer 82

oh AB sorry i was thinking b

Answer 83

Gotcha.

Answer 84

So, that means that when 3 A's are consumed, 2 AB's are produced.

Answer 85

okay, so would the answer be C?

Answer 86

Yep :-)

Answer 87

Okay!