Intro and Thermodynamics

Question 1

total internal energy of a system equation

Answer 1

U = w(work) + q(heat)

Question 2

U - total internal energy of system

Answer 2

transferred from one entity to another as work or heat

Question 3

Form of energy

Answer 3

kinetic and potential

Question 4

kinetic energy

Answer 4

Ek= 1/2mv2

Question 5

potential energy

Answer 5

gravitational and chemical bond energy

Question 6

chemical bond energy

Answer 6

energy stored
formation release energy
bond cleavage requires energy

Question 7

open system

Answer 7

both matter and energy can be transferred

Question 8

closed system

Answer 8

only energy transferred

Question 9

isolated system

Answer 9

no matter or energy is transferred

Question 10

1st law of thermodynamics

Answer 10

sum of energy of system and surroundings is constant

cannot be created or destroyed

Question 11

energy transfer as work

Answer 11

can be used to lift weight

energy transferred from system to surroundings

Question 12

energy transfer as heat

Answer 12

system gets colder when in contact with colder surrounding

irreversible

Question 13

energy change during chemical reaction

Answer 13

H = U + pV
H - enthalpy
p - pressure
V - volume

Question 14

change in enthalpy

Answer 14

DH = DU + D(pV)

Question 15

Endothermic

Answer 15

more energy absorbs from surroundings

+ve

Question 16

Exothermic

Answer 16

more energy released to surroundings

-ve

Question 17

example: burning methane

Answer 17

DH = Sum(E reactant) - Sum(E product)

exothermic

Question 18

example: photosynthesis

Answer 18

always independent whether in plant cell or by chemist in lab

Question 19

Measuring enthalpy changes

Answer 19

using bomb calorimeter

Question 20

bomb calorimeter

Answer 20

exothermic reaction - reaction vessel transfer energy to water bath
increase temp measured by thermometer
in a closed system