General Questions and Answers
Physical Chemistry
GeneralFor a 25.0 % m/v MgCl₂ solution.
1. What is the molarity? The GFW for magnesium chloride is 95.21 g. (hint: find the g in 1000 ml, then convert to moles)
there are 25.0 g in 100. mL, so there are 250. g in 1000. mL
25.0 g
1000. mL
2. What is the osmolarity?
MgCl₂ → Mg¹2
1 mol =
+
a. 250.
b. 100.0
J. 1
k. 6.00 x 10-3
q. 7.65 x 10-10 r. 2.63
2 CH
mol
L
09
osmoles
-X-
C. 2
1. 3.60 x 10-2
S. 7.89
d. 30.00
-X-
osmoles
mol
e. 6 f. 24
m. 6.00 x 10-² n. 5
t. 5.26
u. 95.21
mol
8
09
11
11
g. 3 h. 36
0.3.0 x 10-²
V. 10¹2
1. 18.0
p. 1.80 x 10-2
W. 109
h
M
osmoles/L
Physical Chemistry
GeneralA quantity of 36.4L of methane gas is heated from 25°C to 88°C at constant
pressure. What is its final volume? What law did you use to solve?
Make sure to show all work, for partial credit if your answer happens to be
incorrect.
Equations:
P₁ P₂
V₁
V₂ P₁V₁ P₂V₂
P.V₁ = P_V₂ 2-2 2-1/2 2V AV
=
2
T₁ T₂
T₁ T₂ T₁ T₂
Physical Chemistry
GeneralShow all work!
4. You just got a new job at Tommy's Malt Shop! It is your job to order all the food. To make a
cheese burger you need to follow this recipe: 3 Ch + 1 M + 2 B → 1 Ch3MB₂ In your order one box
contains 1050 pieces of Ch (cheese), 850 M (meat patties), and 1000 B (buns).
->
a. How many total cheese burgers will you be able to make? (SHOW WORK)
1050 ch 1CH3 MB2- 350ch3 MB2 = 10008 x Ich 3 MB2
2-B
3ch
b. What is the limiting ingredient (s)? Why?
c. What is the excess ingredient (s)? Why?
Physical Chemistry
General14
Refer to the chemical equation below to answer your question.
Note: [x] means the concentration of x.
The reaction is at equilibrium. If H3PO4 is added to the reaction system, what is a possible result?
H3PO4 + H₂O → H₂PO4 + H30+
Physical Chemistry
GeneralProblem G The % (v/v) of ethanol in Everclear is 90%. Ethanol has a density of 0.789 g/mL and a
chemical formula of C₂H,O.
(a) Calculate the % (m/v) of ethanol for Everclear.
(b) Calculate the M of ethanol for Everclear.
Physical Chemistry
GeneralHow many microliters of a 856.0 ppm Co²+ stock solution are required to prepare 23.00 mL of a 23.0 ng/μl. Co²+ solution?
Significant figures are graded for this problem. Be sure you do not round your answers until the very end of your calculations.
V =
μL
Physical Chemistry
GeneralLipoprotein complexes carry lipids in the bloodstream. Which of the following lipoproteins carries cholesterol (at least 25% cholesterol by weight)?
(Select all that apply.)
very-low-density lipoprotein
chylomicrons
low-density lipoprotein
high-density lipoprotein
Physical Chemistry
GeneralThe end point of a titration was reached after 21.1 mL of 0.050 M disodium EDTA titrant was dispensed into a solution
containing the zinc ion. Calculate the moles of disodium EDTA used.
Physical Chemistry
GeneralWhich two functional groups are in the molecule shown below? Use the terms left and right to
distinguish them.
H
O
"The left functional group is a carboxylic acid. The
right functional group is an alcohol"
Physical Chemistry
GeneralClassify each substance as an atomic element, molecular element, molecular compound, or ionic compound.
Atomic element
00
Mn
O
Molecular element
8 888
Molecular compound
CO
Ionic compound
FeCl,
Physical Chemistry
GeneralHow many moles of MgCl₂ are needed to make 190 mL of 3.00 M MgCl₂
solution?
0.57 mol
570 mol
O 63 mol
O 0.016 mol
Physical Chemistry
GeneralHydrogen atoms are excited by a laser to the n = 4 state and then allowed to emit.
What is the maximum number of distinct emission spectral lines (lines of different wavelengths) that can be observed from
this system?
01
03
4
5
6
λ=
7
8
Calculate the wavelength of the 41 transition.
IT
Physical Chemistry
GeneralWhat is the energy of a photon of electromagnetic radiation with a wavelength of 623.3 nm? (c = 3.00 x 10 m/s, h = 6.63 × 10-34 J-s) YOU
MUST WRITE ALL CALCULATIONS OTHERWISE YOU WILL NO BE GRANTED FULL CREDIT
O 3.19 x 10-28 J
O 3.19 × 10-¹⁹ J
O 1.38 x 10-3⁹ J
O 4.81 x 10¹4 J
4.13 x 104⁰ J
Physical Chemistry
GeneralAccording to the Star Trek Fifth Interstellar Geophysical Conference Standard version of the periodic table, there are 140
known elements.
In what group of the periodic table would you place element 117, "topaline," which is reported to have been discovered on
Ganymede in 2021?
Group:
If the symbol for topaline is To, predict the formula of a compound that would presumably result from the reaction between
calcium and topaline, and name the compound. Spelling counts.
formula:
name:
Physical Chemistry
GeneralThe next step is to create a conversion factor relating atoms to volume. The structure of Al is shown. The radius of an Al atom is 143.2 pm.
What is the distance of the diagonal of the face of the unit cell, in pm?
Molar volume of Al: 9.996 cm³/mol
Physical Chemistry
GeneralGiven:
4AICI3(s) + 302(g) Ⓡ 2Al2O3(s) + 6Cl2(g); DH = -529.0 kJ
determine DH for the following thermochemical equation. YOU MUST WRITE ALL CALCULATIONS OTHERWISE YOU WILL NO BE
GRANTED FULL CREDIT
Cl₂(g) + Al₂O3(s) ⓇAICI3(s) + O₂(g)
+529.0 kJ
-176.3 kJ
+176.3 kJ
+264.5 kJ
+88.2 kJ
Physical Chemistry
GeneralWhich describes the burning of fossil fuels?
OA. Turbines are used to heat the fuels.
OB. Greenhouse gases are released into the atmosphere.
OC. The reaction is endothermic.
OD. Petroleum is formed because of the heating.
Physical Chemistry
General1. Fill in the diagram (with "high" or "low") to show how intermolecular forces influence the volatility,
vapor pressure, and boiling point of a substance.
volatility is
vapor pressure is
boiling point is
weak
PART B-VAPOR PRESSURE GRAPHS (1 pt each, 4 pts total)
Use the graph below to answer the following questions.
2. What is the vapor pressure of CHCl3 at 50°C?
4. What is the normal boiling point of CCl4?
5. Which substance has the weakest IMF?
Vapor pressure (kPa)
100
3. What is the boiling point of H₂O when the external pressure is 30 kPa?
80
60
40
20
When IMF are...
0
20
40
CHC
60
ca
80
strong
volatility is
vapor pressure is
boiling point is
100
H₂O
101.3 kPa
Physical Chemistry
GeneralThe amount of energy needed to change a material from a solid to a liquid is called the heat
of
O vaporization
evaporation
condensation
fusion
Physical Chemistry
General5) A standard laboratory preparation of iodine is shown the following balanced equation:
2 Nal + MnO₂ + 2 H₂SO, Na₂SO4 + MnSO4 + 2 H₂O + 1₂
What is the percentage yield of I, if the actual yield of I, was 39.78 g when the amount of Nal used was
62.55 g.
=
m
Please show the percent yield formula calculation here:
What is the percent yield?
Physical Chemistry
GeneralBinder: Q4 HO
4. **
Chemistry-Law of Conservation of Matter no [U7 - Lesson 5]
Na2CrO4 +
KCI →>
4310ATT
NaCl +
K₂CRO4
Uncommon
5. Describe the mole ratio between potassium chloride and sodium chloride:
Schools Change Histo
Physical Chemistry
General6) Given the following reactions:
Fe (s) + Br₂ (g) →
3 FeBr₂ (s) + Br₂ (g) →
Fe Brs (S)
If each reaction gives an 82% yield, what mass of FesBr, is produced from 1.00g Fe, assuming Br, is in excess?
A) 4.81 g
B) 3.94 g
C) 2.65 g
D) 3.23 g
E) 2.57 g
FeBr₂ (s)
Physical Chemistry
GeneralAlBr3 + Li₂CO3 --> LiBr + Al2(CO3)3
Balance the chemical equation and then type in the correct coefficient for each
compound.
AlBr3
Li₂CO3
LiBr
Al2(CO3)3
Physical Chemistry
General2 Fe(s) + 0₂ (9)
Keq = 1 x 10 at 1000 K
2 FeO (s)
CO₂ (g)
C(s) + 0₂ (9)
Keq=1 x 10-32 at 1000 K
The formation of Fe(s) and O₂(g) from FeO (s) is not thermodynamically favorable at room temperature. In an effort to make the process favorable, C (s) is added to the FeO (s) at elevated temperatures. Based on the information above, which of the following gives the
value of Keq and the sign of AG" for the reaction represented by the equation below at 1000 K?
B
2 FeO (s) + C(s) 2 Fe(s) + CO₂ (9)
Keg
1 × 10 38
Keq
1 × 10-38
Keq
1 x 1026
Keg
1 x 102
AG
Positive
AG
Negative
AG
Positive
AG
Negative
Physical Chemistry
GeneralFind the amount of heat energy needed to convert 400 grams of ice at -38°C to steam at
160°C.
159984 Joules
1284440 Joules
331056 Joules
246840 Joules
Physical Chemistry
GeneralConsider these reactions:
Reaction 1: H₂(g) + Cl₂(g) → 2HCl(g)
Reaction 2: 20F2 (g) → O₂(g) + 2 F2 (g)
Reaction 3: N₂(g) +202 (g) → 2NO₂ (g)
-
Use Reaction 2.
How much energy (in kJ) is released when 54.0 g of oxygen difluoride decomposes?
Answer: -
AH = -184.6 kJ
AH = -49.4 kJ
AH = +66.4 kJ
kJ (enter a positive value)
Physical Chemistry
GeneralA chemist must prepare 900.0 mL of potassium hydroxide solution with a pH of 13.70 at 25 °C.
He will do this in three steps:
• Fill a 900.0 mL volumetric flask about halfway with distilled water.
• Weigh out a small amount of solid potassium hydroxide and add it to the flask.
. Fill the flask to the mark with distilled water.
Calculate the mass of potassium hydroxide that the chemist must weigh out in the second step. Round your answer to 2 significant digits.
Physical Chemistry
GeneralHow does soap work?
Soap works by breaking grease molecules into smaller molecules that dissolve in water.
Soap works by making water into a nonpolar liquid which grease can dissolve in.
none of the above
Soap works by having a polar end and a nonpolar end which allows the water and oil to
interact indirectly.
Soap works by having a polar end which attaches to the grease molecule and polarizes it and turns the grease molecule into another soap molecule. This is a chain reaction.
Physical Chemistry
GeneralA chocolate chip cookie contains 12 Calories. Convert this energy into calories.
1 Calorie = 1 kcal = 1000 cal
1cal=4.184 J
1 kJ = 1000 J
Make sure to show all work for partial credit if your answer happens to be incorrect.
Physical Chemistry
GeneralWhich of the following is an example of kinetic energy?
a phase change
a book in a backpack
chemicals sitting on a shelf
particles of a gas moving about in random motion
Physical Chemistry
GeneralWhen 2.13 g of a nonelectrolyte solute is dissolved in water to make 615 mL of solution at 25 °C, the solution exerts an osmotic pressure of 879 torr.
What is the molar concentration of the solution?
concentration:
How many mole
moles of solute:
What is the molar mass of the solute?
Physical Chemistry
GeneralUse the scenario to answer the following question.
A group of students working in a chemistry lab is planning a procedure to neutralize
25.0mL of 2.0 M hydrochloric acid (strong acid) with 1.0 M potassium hydroxide
(strong base). In their procedure they plan on adding an equal volume of the base to
the acid.
What would be the expected outcome of carrying out this step as planned?
The resulting pH will not be able to be determined because the concentrations
of the acid and base are not the same.
The resulting pH will be greater than 7 because potassium hydroxide is less
concentrated than the hydrochloric acid.
The resulting pH will be equal to 7 because a strong base will neutralize a strong
acid.
The resulting pH will be less than 7 because potassium hydroxide is less
concentrated than the hydrochloric acid.
Physical Chemistry
GeneralGive the formula for the conjugate base of each acid.
a. HNO₂
b. NH4
c. H₂02
Physical Chemistry
GeneralWhat mass of propane, C3H8, must be burned in order to produce 76,000 kJ of energy?
Circle one: Is this reaction endothermic or exothermic?
Additionally, rewrite the thermochemical equation in the other format.
C3H8 +502 → 3CO2 + 4H₂O + 2200 kJ
Physical Chemistry
GeneralA candy bar contains 250 Calories. How many joules of energy are in this candy bar?
1 Calorie=1 kcal = 1000 cal
1cal=4.184 J
1 kJ=1000 J
Make sure to show all work for partial credit if your answer happens to be incorrect.
Physical Chemistry
GeneralIt takes 487.5 J to heat 25.0 g of an unknown metal from 25°C to 75°C. What is the specific heat of the metal?
Q=mx cx AT
Make sure to show all work for partial credit if your answer happens to be incorrect.
Physical Chemistry
GeneralThese two sentences appear in a paragraph: "Sally loves horses." "Sally hates cowboy
movies." If you combine these two sentences into one sentence, using the conjunction "yet," your new sentence will have a
compound predicate.
compound subject.
complex predicate.
complex subject.
Physical Chemistry
GeneralThe molecule C₂H₂Cl₂ has three possible Lewis Structures. When a single molecular formula can apply to different molecules with different properties, the molecules are called isomers.
Draw Lewis structures for all 3 isomers of C₂H₂Cl₂.
Circle any of these isomers which are polar
Physical Chemistry
GeneralA patient with respiratory alkalosis has a blood plasma pH of 7.53. What is the [H3O+] of the blood plasma?
Express your answer to two significant figures and include the appropriate units.
Physical Chemistry
GeneralFor the unbalanced equation
NaClO3 -> NaCl + 02
how many moles of Og can be obtained from 1.50 mol NaClO3?
O2.50 mol O₂
1.50 mol O₂
2.25 mol O₂
O3.00 mol O₂
Physical Chemistry
GeneralArrange the following elements in order of decreasing first ionization energy.
(Hint: think about half-filled and completely filled orbitals)
Highest lonization Energy
Be
O
B
C
N
Lowest lonization Energy
Physical Chemistry
GeneralWhich of the following would have the highest concentration of [OH-] in solution?
HCO3
NO₂
HCI
CN
H₂S
Physical Chemistry
GeneralRead the following chemical equation.
Fe(s) + O2(g) → Fe³+ 02-
What most likely happens during this reaction?
Iron loses three electrons.
Iron gains three electrons.
Oxygen loses one electron.
Oxygen gains one electron.
Physical Chemistry
GeneralIsomers must have the same
Ochemical structure
O Lewis Dot diagram
O carbon parent chain
O chemical formula
Physical Chemistry
GeneralIn the reaction between CO and Fe3O4, the theoretical yield in an experiment is calculated to be 47.2 g Fe.
When a careless chemistry student carries out the experiment, the actual yield is 35.6 g Fe. Calculate the
percentage yield.
75.4%
O 24.6%
O 50.3%
O 37.7%
O none of these.
Physical Chemistry
GeneralComplete and balance the following neutralization reaction:
NaOH(aq) + HC₂H₂O₂(aq) -->
What are the products of this reaction before balancing?
NaCl and H₂O
Na2C₂H3O2 and H₂O
NaC₂H3O2 and H₂O
NaCl2 and H₂O
no reaction
Physical Chemistry
GeneralA calorimeter
1. is an indicator of spontaneity.
2. is equal to the molar enthalpy of reac-tion.
3. is only useful in measuring exothermic re-actions.
4. is a dieting aid.
5. is a device used to measure the transfer of heat energy.
Physical Chemistry
GeneralFor each reaction below:
- Assign Oxidation Numbers
- Identify which atom/compound is oxidized and which atom/compound is reduced
- Identify the oxidizing agent and the reducing agent
Underneath each, write the oxidation half reaction and the reduction half reaction.
-
2.
2Fe + 3V₂O3 → Fe2O3 + 6VO
Physical Chemistry
GeneralA particular sample of vinegar has a pH of 3.20.
▼
Part A
If acetic acid is the only acid that vinegar contains (Ka = 1.8 x 10-5), calculate the initial concentration of acetic acid in the vinegar.
Express your answer using two significant figures.
Physical Chemistry
GeneralAn alcohol is 58.80 % C and 9.889 % H by mass. The rest is oxygen. What is the empirical formula of the alcohol? Enter the elements in the order C, H, and then O.
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