WorksheetsUnit 4 Part 2 OnRamps Chemistry
Total questions: 53
Worksheet time: 45mins
Is this an example of an isolated, closed, or open system?
isolated
closed
open
Is this an example of an isolated, closed, or open system?
isolated
closed
open
Is this an example of an isolated, closed, or open system?
isolated
closed
open
When work is being done by the system the sign is.
positive
negative
When work is being done on the system the sign is.
positive
negative
q represents _____.
heat
enthalpy
reaction energy
kinetic energy
w represents ______
work
wasted energy
Waltzmann's constant
heat
H represents ___ .
Entropy
Enthalpy
Internal Energy
Gibbs Free Energy
S represents ___ .
Entropy
Enthalpy
Internal Energy
Gibbs Free Energy
U represents ___ .
Entropy
Enthalpy
Internal Energy
Gibbs Free Energy
G represents ___ .
Entropy
Enthalpy
Internal Energy
Gibbs Free Energy
A reaction is spontaneous when...
ΔGrxn is positive
ΔSuniv is positive
ΔGrxn is negative
ΔSuniv is negative
Which of the following reactions have an increase in entropy?
2 H2 (g)+ O2 (g) → 2 H2O (l)
Mg(s) +2 HCl (aq) → H2 (g) + MgCl2 (aq)
H2O (l) → H2O (g)
Which of the following statements concerning the first law of thermodynamics is true
The internal energy of the universe is conserved
The change in internal energy of a system and the surroundings can have the same sign
The entropy of the universe is always decreasing
The internal energy changes are only determined by gases.
A chromebook battery has a change in internal energy, ΔE , of 1000 kJ as it powers the computer. If 50 kJ is warming the desk it is sitting on, how much work was done to watch a video.
1050 kJ
-1050 kJ
9050 kJ
-9050 kJ
What is the total change in internal energy when your cell phone uses 30 kJ to light up and releases 30 kJ of heat into your hand.
60 kJ
-60 kJ
0 kJ
900 kJ
If the specific heat of water is 4 J/g∙°C, how much heat is required to increase the temperature of 10 g of water from 20 °C to 40 °C? (show your work)
-800 J
800 J
800 KJ
-800 KJ
For a skillet, used for cooking, do you want a high or low specific heat
High, so that it will need more energy to heat up
Low, so that it will change temperature quickly
A reaction is performed in a beaker with a temperature probe recording the temperature changes of the surroundings. If the temperature began at 15.0 degrees Celsius and ended at 27.5 degrees Celsius. Is the reaction endothermic or exothermic?
The specific heat of water is 4J/g°C.
If 2400 J of energy is added to 6 g of water at 18.0 °C, what is the final temperature of the water?
18 °C
78 °C
100 °C
118 °C
What does "ΔT" mean?
A change in health
A change in heat
A change in height
A change in temperature
Using the equations below:
C(s) + O2(g) → CO2(g) ∆H = –400 kJ
Mn(s) + O2(g) → MnO2(s) ∆H = –500 kJ
what is ∆H (in kJ) for the following reaction?
MnO2(s) + C(s) → Mn(s) + CO2(g)
900
100
-100
-900
Using the equations below
Cu(s) + 1/2O2(g) → CuO(s) ∆Hf = –150 kJ
2Cu(s) + 1/2O2(g) → Cu2O(s) ∆Hf = –170 kJ
what is the value of ∆H (in kJ) for the following reaction?
2CuO(s) → Cu2O(s) + 1/2O2(g)
130
20
-20
-130
Consider the following equations.
Mg(s) + O2(g) → MgO(s) ∆H = –600 kJ
H2(g) + O2(g) → H2O(g) ∆H = –250 kJ
What is the ∆H value (in kJ) for the following reaction?
MgO(s) + H2(g) → Mg(s) + H2O(g)
-850
-350
+350
+850
Which of the following statements are true for the reaction:
SO2(g) + 1/2O2(g) ↔ SO3(g)
ΔH = –92 kJ mol-1
Where ↔ indicates that the reaction can proceed in the forward and the reverse direction.
The forward and reverse reaction both produce 92 kJ of energy.
Oxidizing 2 moles of SO2 would produce twice as much energy.
The reverse reaction has an enthalpy of +92 kJ mol-1.
Collecting the SO3 produced in the liquid state would not change the measured enthalpy.
The standard enthalpy change of formation values of two oxides of phosphorus are:
P4(s) + 3O2(g) → P4O6(s) ΔHf = –1600 kJ mol–1
P4(s) + 5O2(g) → P4O10(s) ΔHf = –3000 kJ mol–1
What is the enthalpy change, in kJ mol–1, for the reaction below?
P4O6(s) + 2O2(g) → P4O10(s)
+4600
+1400
–1400
–4600
If N2 (g) + 2O2 (g) ⟶ 2NO2(g) has a ΔHrxn = 68, then what is the ΔHrxn if you reverse the reaction?
86 kJ
- 86 kJ
68 kJ
-68 kJ
Which of the following statements must be true if ΔG is negative.
The reaction is nonspontaneous
The reaction is exothermic
The reaction is at equilibrium
The entropy could be positive or negative
What is the symbol for entropy?
H
G
S
E
Entropy is a measure of
accuracy
precision
possible microstates
the attraction of a nucleus for an electron
Which of these processes represents a decrease in entropy?
sublimation of CO2
boiling water
condensation of steam on cold glass
NaCl dissolving in water
Which of these reactions shows a DECREASE in entropy?
CaCO3(s) → CaO(s) + CO2(g)
3O2(g) → 2O3(g)
2NH3(g) → 3H2(g) + N2(g)
C6H6(l) → C6H6(g)
The entropy will usually increase when
a molecule is broken into two or more smaller molecules
a reaction occurs that results in an increase in the number of moles of gas
a solid changes to a liquid
all of these
Which reaction has a +ΔS ?
AgNO3(aq) + NaCl(aq) → AgCl(s) + NaNO3(aq)
H2O(g) + CO2(g) → H2CO3(aq)
H2(g) + I2(g) → 2Hl(g)
C2H2O2(g) → 2CO(g) + H2(g)
Which sample has the lowest entropy?
1 mole of KNO3(l)
1 mole of KNO3(s)
1 mole of H2O(l)
1 mole of H2O(g)
Which phase change represents a decrease in entropy?
solid to liquid
gas to liquid
liquid to gas
solid to gas
Which sample has the greatest entropy?
1 mole of KNO3(l)
1 mole of KNO3(s)
1 mole of H2O(l)
1 mole of H2O(g)
Which sample has the greatest entropy?
1 mole of CH4(l)
1 mole of C3H8(s)
1 mole of C2H4(l)
1 mole of C6H12(g)
Which sample has the greatest entropy?
1 mole of CH4(l)
1 mole of C3H8(s)
1 mole of C2H4(l)
1 mole of C6H12(g)
Your enthalpy is high and negative but your entropy is also negative. What type of temperature would you want to get a spontaneous reaction?
low
high
Your enthalpy is positive and your entropy is positive. What type of temperature would you want to ensure a spontaneous reaction.
very high
very low
Which of the following situations demonstrates high entropy?
water freezing
water vaporizing
steam condensing to water
For which of the following processes would ΔS have a negative value (look at the states s, l, or g) ?
i. 2Fe2O3 (s) → 4Fe(s)+3O2(g)
ii. Mg2+(aq)+2OH-(aq) → Mg(OH)2(s)
iii. H2(g) + C2H4(g) → 3C2H6(g)
I only
I and II only
I and III only
II only
NH3(g) + 2CH4(g) + 5/2 O2(g) → H2NCH2COOH(s) + 3H2O(l), ΔS is...
increasing
decreasing
staying the same
speeding up
What is the equation for Gibbs Free Energy Change?
ΔG = ΔH + TΔS
ΔH = ΔG - TΔS
ΔS = ΔH - TΔG
ΔG = ΔH - TΔS
1. Calculate the standard entropy change for the following reaction: Cu(s)+ 1/2 O2(g) → CuO(s). Given that
S0 (Cu(s)) = 30 J/K*mol
S0 (O2(g)) = 200 J/K*mol
S0 (CuO(s)) = 40 J/K*mol
-200 J/K.mol
90 J/K.mol
-90 J/K.mol
+200 J/K.mol
For the process at 250C : I2(g) →I2(s). What are the signs for ΔG, ΔH and ΔS?
ΔG ΔH ΔS
+ - -
ΔG ΔH ΔS
- - -
ΔG ΔH ΔS
- + +
ΔG ΔH ΔS
- + +
If a process is exothermic and not spontaneous, then what must be true?
ΔSsys > 0
ΔHsys > 0
ΔGsys = 0
ΔSuniv < 0
In which of the following reactions do you expect to have a decrease in entropy?
Fe(s) →Fe(l)
H2O2(l) →2H2O(l) +O2(g)
2Fe(s) +3/2O2(g)→Fe2O3(s)
HF(l) →HF(g)
If ΔH and ΔS are both negative or positive, then ΔG has a -------------------sign.
Positive
Negative
Large
Variable
