Enthalpy & Heat.

Question 1

What is Energy?

Answer 1

The capacity to supply heat or do work

Question 2

What is w?

Answer 2

Work: quantity of energy transferred from one system to another relating to mechanical energery. EX: a change in volume against a pressure. Measured in J

Question 3

How to type ∆?

Answer 3

opt J

Question 4

What is q?

Answer 4

q is the measure of Heat in J
Genereally a measure of all heat in & out of a system.

Question 5

∆U

Answer 5

The change in internal energy of a system.

Question 6

∆U=q (+/-) w

Answer 6

1st law of thermodynamics: that defines the relationship between work and heat

Question 7

ºF to ºC

Answer 7

(ºF)-32*5/9

Question 8

ºF to K

Answer 8

Convert to ºC then add 273.15

Question 9

ºC to K

Answer 9

Add 273.15

Question 10

K to ºC

Answer 10

Subtract 273.15 K

Question 11

ºC to ºF

Answer 11

(ºC)*9/5 +32

Question 12

Relationship between enthalpy and entropy.

Answer 12

∆G=∆H-T∆S

Question 13

What is H?

Answer 13

Enthalpy- the Measure of heat within a system, usually written as ∆H to determine the change of energy within a chemical reaction, since H on it’s own if very difficult to measure. typically measured in STP

Question 14

What is K_c

Answer 14

The ratio of equilibrium between the products and the reactants at equlibrium.

Question 15

How to Calculate K_c

Answer 15

Products/ Reactants.

Question 16

What does a Large K_c Mean?

Answer 16

There are more products than reactants at equilibrium.

Question 17

What does K_c less than 1 Mean?

Answer 17

There are more Reactants than products at equilibrium.

Question 18

What is Q?

Answer 18

The reaction quotient this is calculated the same way as K

Question 19

Q<K?

Answer 19

Reaction will shift towards the Products- Forward reaction.

Question 20

Q>K?

Answer 20

Reactions Will shift towards the reactants- Reverse Reaction.

Question 21

Enthalpy Equation?

Answer 21

H= U+PV

Question 22

U?

Answer 22

Internal energy of a system.

Question 23

H>0?

Answer 23

Endothermic- absorbs heat

Question 24

H<0?

Answer 24

Exothermic- Releases heat.

Question 25

STP

Answer 25

P: 1 ATM or Bar, T: 273.15 K/ 0ºC

Question 26

Standard State Conditions:

Answer 26

P: 1 ATM or Bar, T: 298K/ 25ºC

Question 27

How to calculate enthalpy using Chemical Equations?

Answer 27

∆H= the sum of the products - the sum of the reactants.

Question 28

C_s?

Answer 28

Specific heat capacity at a constant pressure.

Question 29

Why is ∆H=mC_s∆T

Answer 29

Most ∆H are done at a constant pressure, making the ∆P=0 and there there PV=0 so it just leaves U/q

Question 30

What is Entropy?

Answer 30

The measure of disorder within a system. A high entropy will have a lot of disorder and a low entropy will have less disorder.

Question 31

What is G (Gibbs)

Answer 31

The measure of spontaneity/ free energy within a system. this is related by entropy and enthalpy.

Question 32

∆S?

Answer 32

The change of entropy within a system.

Question 33

-∆G

Answer 33

Spontaneous

Question 34

+∆G

Answer 34

Non-Spontaneous.

Question 35

How to calculate ∆S(surroundings)?

Answer 35

∆S= (-1)∆H/T

(T is in K)

Question 36

If ∆H (-) & ∆S (+)?

Answer 36

The reactions will always be spontaneous.

Question 37

If ∆H (+) & ∆S (-)?

Answer 37

The reaction will never be spontaneous.

Question 38

If ∆H (+) & ∆S (+)?

Answer 38

The reaction will be spontaneous at high temperatures.

Question 39

If ∆H (-) & ∆S (-)?

Answer 39

The reaction will be spontaneous at low temperatures.

Question 40

What Happens when you add heat to an endothermic reversible reaction?

Answer 40

The reaction will shift towards products.