HChem Test Chapter 17 Flashcards Preview

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

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

A

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

2
Q

What is the equation to find Qwater

A

Mass * 4.184 * delta T

3
Q

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

A

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

4
Q

Heat lost by metal=

A

Heat gained by water (make -)

5
Q

When solving an equation, make sure your units ______

A

Agree (kJ, mole, Kelvin for Gibbs)

6
Q

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

A

1

Combustion

7
Q

What is the typical combustion equation

A

__+O2—>CO2+H2)

8
Q

What is Hess’s Law

A

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

9
Q

What is the summation equation

A

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

10
Q

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

A

1

Don’t do this is asked to find the heat of reaction for the entire process

11
Q

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

A

Exothermic

Endothermic

12
Q

Positive delta S means _______

A

More disorder

13
Q

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

A

Endothermic

14
Q

An ____ reaction produces energy as it proceeds

A

Exothermic

15
Q

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

A

Lower energy, higher disorder

16
Q

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

A

Enthalpy
Entropy
Gibbs

17
Q

What is the formula for Gibbs

A

Delta G=delta H-(T*deltaS)

T must be in kelvin

18
Q

-delta G is ____

A

Spontaneous

19
Q

If a reaction is spontaneous it does not need _____ help

A

Outside (catalyst)

20
Q

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

A

Bottom, top

21
Q

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

A

How talk it is (y axis)

22
Q

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

A

Concentration, temperature, catalyst, surface area

23
Q

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

A

Axes, title

24
Q
  • heat is equal to __________
A

Heat released (you can say either/or)

25
Q

When finding a limited reactant, what do you do

A

Go from grams of the reactant to grams of the product

Whichever is less is limiting reactant

26
Q

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

A

Molar mass

27
Q

qH2O=___

A

-qrxn

28
Q

What is the Hf value for elements

A

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

29
Q

Delta H =

A

qrxn/moles

30
Q

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

A

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

31
Q

1.00 ml of water=

A

1.00 g of water

32
Q

When doing specific heat equation, put temp in ___

A

C

33
Q

What is the second law of thermodynamics

A

Changes in the universe tend towards a state of greater disorder

34
Q

More moles to less moles is __ delta S

A

-

35
Q

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

A

-,+

36
Q

The equation for the delta Hf of N2O is:

A

N2(g)+3/2O2(g)—>N2O3(g)

37
Q

Disorder is ___ delta S

A

+

38
Q

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

A

Summation

39
Q

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

A

02 or H2

40
Q

Delta H must be in ___

A

kJ/mol