thermodynamics

Question 1

what is an open system?

Answer 1

able to exchange heat, work and matter with surrounding

Question 2

what is closed system ?

Answer 2

able to exchange heat and work but NOT matter with the surroundings

Question 3

what is an isolated system?

Answer 3

not able to exchange heat , work and matter with surroundings

Question 4

what is the ideal gas equation?

Answer 4

pV = nRT

p= pressure (atm)
V=volume occupied by gas (L)
n=number of moles od substance in gaseous state
T= temperature (Kelvin) +273
R= ideal gas constant (L.K-1.mol-1)

Question 5

give 2 example of non thermodynamic properties

Answer 5

heat (q)
work (w)

Question 6

what is heat in thermodynamics?

Answer 6

heat is the exchange of energy between thermodynamic systems by thermal interactions.

Question 7

what is molar heat capacity cm? J K-1 mol-1

Answer 7

Amount of energy required to increase the temperature of 1 mol of a substance by 1 Kelvin.

Question 7

what is work in thermodynamic systems?

Answer 7

work is then exchange of energy between thermodynamic. systems by any other interaction than thermal.

Question 8

what is specific heat capacity cs? J K-1 g-1

Answer 8

Amount of energy required to increase the temperature of 1 g of a substance by 1 Kelvin.

Question 9

what is the equation for heat energy?

Answer 9

q = m x c x change in T

the c can be cs or cm

q= heat energy
m= mass in grams
n= number of moles
cs= specific heat capacity
cm= molar heat capacity
T= change in temperature (K)

Question 10

what is the first law of thermodynamics?

Answer 10

states that the internal energy (U) is the total energy of a thermodynamics system.

Question 11

what is the equation for internal energy?

Answer 11

sum of heat energy and work

ΔU = q + ω

Question 12

what is bond energy?

Answer 12

the amount of energy stored in a chemical bond between two atoms

Question 13

how do you calculate total energy stored in a compound?

Answer 13

find all the bonds in the compound and add all the energy together that is stored to find the total energy

Question 14

what is the equation for enthalpy

Answer 14

ΔH = sum E(reactants) – sum E(products)

Question 15

what are exothermic reactions?

Answer 15

the sum of energy of bonds formed is greater than the sum of energy of bonds broken

energy released from system

Question 16

what is endothermic

Answer 16

sum of energy of bonds formed is smaller than sum of energy of bonds broken.

energy used

Question 17

as water boils and evaporates the water molecules progress from a more ordered state to a more disordered state of steam. true or false?

Answer 17

true

Question 18

what does entropy (S) mean?

Answer 18

a measure of disorder in thermodynamic system

Question 19

what is the second law of thermodynamics?

Answer 19

states that any spontaneous process must lead to an increase in the disorder of the system and therefore lead to an increase in entropy.

Question 20

equation for Gibbs free energy?

Answer 20

ΔG = ΔH – TΔS

s= entropy
T= temp

Question 21

what is the third law of thermodynamics?

Answer 21

is related to the entropy of the thermodynamic system and states that the entropy of a perfect crystalline material is zero at T= 0K