quiz 5

Question 1

law of conservation of energy formula

Answer 1

(KE + PE)initial = (KE + PE)final

Question 2

how many calories is in 1 kcal?

Answer 2

1000 cal per 1 kcal

Question 3

how many J in 1 Kilowatt-hour

Answer 3

3.60 x 10^6 J per Kilowatt-hour

Question 4

What is a system?

Answer 4

system consists of those molecules which are reacting

Question 5

What is the surroundings in an experiment?

Answer 5

everything else that is not the system?

Question 6

what are the three types of systems?

Answer 6

open, closed, and isolated

Question 7

what is an open system?

Answer 7

energy can flow in and out

matter can flow in and out

Question 8

what is a closed system?

Answer 8

if closed beaker, matter can not flow in or out

Question 9

what is a closed system?

Answer 9

if closed beaker, matter can not flow in or out

Question 10

what is an isolated system?

Answer 10

insulated, energy cant flow in or out

Question 11

what are the 2 types of energy transfer?

Answer 11

exothermic and endothermic

Question 12

what is exothermic?

Answer 12

heart flows out from the system to the surrondings

Question 13

what is endothermic?

Answer 13

heat flows in from the surrounding to the system

Question 14

endo or exothermic: propane burning?

Answer 14

exothermic

Question 15

endo or exothermic: food cooking?

Answer 15

endothermic

Question 16

endo or exothermic: dry ice subliming?

Answer 16

endothermic

Question 17

endo or exothermic: metal reacting with acid?

Answer 17

exothermic

Question 18

what is internal energy (U)?

Answer 18

sum of PE and KE of a system

Question 19

what are the properties of a state function?

Answer 19

the value does not depend on how it got there, change only asks for start and end points, state functions deal with change

Question 20

what is the opposite of a state function

Answer 20

a path function

Question 21

what is the formula for deltaUniverse

Answer 21

deltaSystem + deltaSurrounding=0

Question 22

why is deltaSurroundings + deltaSystem =0?

Answer 22

because energy is conserved, theres no change

Question 23

Why is deltaSystem + deltaSurrounding=0?

Answer 23

because energy is conserved; no change

Question 24

what is the equation of deltaU

Answer 24

q + w

Question 25

what does q stand for

Answer 25

heat

Question 26

what does w stand for

Answer 26

work

Question 27

what is there no delta in front of q and w

Answer 27

because you can not keep heat or work; also it is a transfer of work

Question 28

work formula

Answer 28

w= -P(deltaV)

Question 29

What happens if the gas in a system expands?

Answer 29

deltaV > 0 | w<0

Question 30

What happens if the gas in a system compresses?

Answer 30

deltaV<0 | w>0

Question 31

What happens if the gas in a system does not change in volume?

Answer 31

deltaV=0 | w=0

Question 32

what happens (in terms of heat and work) in a combustion reaction?

Answer 32

heat is transferred out of the fuel | work is being done by the fuel

Question 33

if the fuel is the system in a combustion reaction, what are the signs of q and w and deltaU?

Answer 33

q<0 w<0 deltaU<0

Question 34

What are the two heat equations?

Answer 34

q=C (deltaT) | q=m(Cs)deltaT

Question 35

what is the different between the two heat equations?

Answer 35

the one with mass and specific heat (Cs) is used if dealing with a pure substance

Question 36

what is the sign of heat if it is cooling down?

Answer 36

negative

Question 37

is cooling down endo or exothermic reactions?

Answer 37

exothermic

Question 38

what kind of sign will heat have if it is an exothermic reaction?

Answer 38

negative

Question 39

what is constant in a bomb calorimetry

Answer 39

volume

Question 40

since volume is constant in a bomb calorimetry what is the equation for work

Answer 40

work = 0 so: -PdeltaV=0

Question 41

what kind of system is a bomb calorimetry?

Answer 41

isolated

Question 42

since the bomb calorimetry is an isolated system what happens to q?

Answer 42

The sum is =0

Question 43

how do you tell if volume will increase

Answer 43

look at balanced equation and moles

Question 44

in an isolated system what happens to deltaU

Answer 44

it would always be the same because it is a state function

Question 45

what is the formula used when working with a bomb calorimetery

Answer 45

qrxn + qcal = 0 | qrxn + C(deltaT) = 0

Question 46

what happens to the pressure in a coffee cup calorimetry?

Answer 46

pressure stays constant

Question 47

what happens to deltaUuniverse in a coffee cup calorimetry?

Answer 47

delaUuniverse=0

Question 48

what is the equation for an aqueous reaction?

Answer 48

0= qrxn + qwater + qcal