HChem Test Chapter 17 Flashcards Preview

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Flashcards in HChem Test Chapter 17 Deck (40):
1

When solving an equilibrium equation (think lab) make sure to...

Make the side losing the heat negative (make sure answer makes sense

2

What is the equation to find Qwater

Mass * 4.184 * delta T

3

What is the equation to solve for an equilibrium with a metal

Mass(m)*Cp(m)*delta T(m)=Mass(w)*4.184*deltaT(w)

4

Heat lost by metal=

Heat gained by water (make -)

5

When solving an equation, make sure your units ______

Agree (kJ, mole, Kelvin for Gibbs)

6

When doing heat of formation, make sure that the thing being combusted has a coefficient of ____
These are _________

1
Combustion

7

What is the typical combustion equation

__+O2--->CO2+H2)

8

What is Hess's Law

Regardless of the multiple stages or steps of a reaction, the total enthalpy change for the reaction is the sum of all changes

9

What is the summation equation

Sum of all products' heat of formation-sum of all the reactants' heat of formation
(Multiply by coefficients)

10

If you are asked to calculate the heat of combustion for butane for a specific compound, make that compound's coefficient ____

1
(Don't do this is asked to find the heat of reaction for the entire process)

11

If energy is being added on product side, the reaction is _____
If energy is being added on reactant side, the reaction is _____

Exothermic
Endothermic

12

Positive delta S means _______

More disorder

13

If something needs a continuous energy supply, it is most likely ____

Endothermic

14

An ____ reaction produces energy as it proceeds

Exothermic

15

What is the "direction" or trend most chemical reactions move toward in terms of energy and disorder

Lower energy, higher disorder

16

Delta H stands for ___
Delta S stands for ___
Delta G stands for __

Enthalpy
Entropy
Gibbs

17

What is the formula for Gibbs

Delta G=delta H-(T*deltaS)
T must be in kelvin

18

-delta G is ____

Spontaneous

19

If a reaction is spontaneous it does not need _____ help

Outside (catalyst)

20

The heat content of the activated complex of any reaction is the ___ to the _____

Bottom, top

21

The heat content of anything (reactants, products, AC) is ____

How talk it is (y axis)

22

Name 4 things that will speed up or slow down a chemical reaction

Concentration, temperature, catalyst, surface area

23

When drawing a graph, label the _____ and give it a ____

Axes, title

24

- heat is equal to __________

Heat released (you can say either/or)

25

When finding a limited reactant, what do you do

Go from grams of the reactant to grams of the product
Whichever is less is limiting reactant

26

When doing dimensional analysis, remember that if the element is diatomic, factor that into ____

Molar mass

27

qH2O=___

-qrxn

28

What is the Hf value for elements

0 (they are naturally occurring and no heat is absorbed)

29

Delta H =

qrxn/moles

30

When doing enthalpy calorimetry and finding final temperature, what do you do

Set enthalpy =qrxn/moles, find moles, cross multiply to find qrxn, turn it negative and set equal to mass, Cp, and Tf-Ti

31

1.00 ml of water=

1.00 g of water

32

When doing specific heat equation, put temp in ___

C

33

What is the second law of thermodynamics

Changes in the universe tend towards a state of greater disorder

34

More moles to less moles is __ delta S

-

35

The tendency for all reactions is to have __delta H and __ delta S

-,+

36

The equation for the delta Hf of N2O is:

N2(g)+3/2O2(g)--->N2O3(g)

37

Disorder is ___ delta S

+

38

The equation for Hf is not _______, but you write the equation for one mole of the compound asked

Summation

39

The equation for the delta Hf of any molecule always contains either __ or ___

02 or H2

40

Delta H must be in ___

kJ/mol