thermodynamics :( Flashcards

1
Q

all the names for heat

A

ΔH, enthalpy, Q

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2
Q

when does heat stop transferring

A

when temperatures are equal

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3
Q

if you touch a hot lightbulb what is system and surrounding

A

finger is system, lightbulb is surrounding

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4
Q

endothermic

A

system absorbes heat, +ΔH, reactants have higher energy than products

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5
Q

exothermic

A

system loses heat, -ΔH, reactants have lower energy than products

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6
Q

specific heat of water

A

4.18 JOULES

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7
Q

equation for heat

A

heat= (mass (g)) (C) (ΔT)
C=specific heat
ΔT= difference in heat in celsius

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8
Q

what is heat of fusion (ΔHfus)

A

energy required to melt a solid

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9
Q

what is heat of vaporization (ΔHvap)

A

energy required to vaporize liquid

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10
Q

what type of lattice does a solid have

A

crystalline (exceptions- glass, plastic, wax, and putty are amorphous)

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11
Q

in a heating curve graph, what does each line represent?

A

from origin, the diagonal lines are solid, liquid, gas.
Straight lines are melting and boiling point

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12
Q

what is the relationship between slope of a heating curve graph and specific heat

A

steeper slope= lower specific heat

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13
Q

melting and boiling point of H20

A

melting=0, boiling=100

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14
Q

steps for finding energy of phase changes

A

1) find heat of given phase
2) use stoich to go from given phase to the next one
3) find heat of the phase from part 2
4) repeat 1-2 if there’s another phase

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15
Q

when dealing with dissolution in thermo problems what do you do to the masses

A

add them

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16
Q

what is the ΔHf° of a pure element

A

0

17
Q

equation for ΔH°rxn

A

ΔH°rxn= ΔHf° products- ΔHf° reactants

18
Q

equation for ΔHrxn (bond energy)

A

ΔHrxn= ΔHreactants- ΔHproducts

19
Q

what are the four ways to manipulate equations for Hess’ Law

A

flip, multiply, divide, Add

20
Q

what is entropy

A

ΔS, or available microstates

21
Q

what are the four ways to increase ΔS

A

1) increase molarity
2) increase volume
3) make a mixture
4) increase temp

22
Q

equation of ΔS°system

A

=ΔS°products-ΔS°reactants Pure elements are NOT zero

23
Q

equation of ΔS surroundings

A

ΔSsurr= -ΔH/T
T=temp in Kelvin

24
Q

how to find kelvin

A

C° +273

25
Q

Spontaneous

A

A reaction occurs without external energy input

26
Q

When is a chemical reaction favored

A

when it occurs (-ΔG, +Ecell)

27
Q

ΔG equation

A

ΔG=ΔH- T(ΔS)
T= temp in kelvin

28
Q

Favored conditions for ΔH and ΔS

A

-ΔH, +ΔS= favored under all conditions
+ΔH, -ΔS= never favored
-ΔH, -ΔS= more favored as temp decreases
+ΔH, +ΔS= more favored as Temp increases

29
Q

equation of ΔG°

A

ΔG°= ΔG° products- ΔG° reactants