General Questions and Answers
Physical Chemistry
GeneralUse the balanced equation in the image below. How many moles of ammonia (NH3) will be produced if 2.22 moles of nitrogen (N2) are used? (Assume there is excess hydrogen gas.) SHOW YOUR WORK TO RECEIVE CREDIT. * N₂ + 3H₂ → 2 NH3
Physical Chemistry
GeneralFor each of the elements listed, and using a periodic table, how many protons, electrons and neutrons does each
element have in a normal neutral ground state configuration.
a. Chromium
b. Vanadium
c. Lead
d. Barium
Physical Chemistry
GeneralVanadium (V) oxide is decomposed into the elements sodium and chlorine by means of electrical energy. How many grams of Sulfur dioxide gas can be obtained from the production of 5.50 mol V₂O5?
Physical Chemistry
GeneralA 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 equal to 7 because a strong base will neutralize a strong
acid.
The resulting pH will be greater than 7 because potassium hydroxide is less
concentrated than the hydrochloric acid.
The resulting pH will be less than 7 because potassium hydroxide is less
concentrated than the hydrochloric acid.
Physical Chemistry
GeneralHow do gas particles respond to an increase in volume?
Increase in kinetic energy and increase in temperature
Increase in Kinetic energy and decrease in temperature
Decrease in kinetic energy and decrease in pressure
Increase in temperature and increase in pressure
Physical Chemistry
GeneralWhat is the empirical formula of a compound that is 75% carbon and 25% hydrogen? The molar mass of a sample of this compound is 32 g/mol. What is the molecular formula?
Physical Chemistry
GeneralGiven the following equation:
2 K₂O₂ (s) + 2 H₂O(1)→ O₂(g) + 4 KOH(aq)
How many grams of H₂are needed to produce 0.18 moles of KOH? (molar mass of H₂= 18.0 g/mole)
1.6 grams
2.5 grams
3.2 grams
6.5 grams
Physical Chemistry
GeneralAccording to this chemical reaction, what is the number of grams of Fe produced from 9.40 moles of H₂? Do not include units in your answer. Round to the tenths place or further.
Fe3O4 (cr) + 4H₂ (g) - 3 Fe (cr) + 4H₂O (1)
Physical Chemistry
GeneralWhy are some isotopes radioactive and others are not radioactive?
radioactive isotopes have too many or not enough neutrons
radioactive isotopes have too many or not enough protons
radioactive isotopes have too many or not enough positrons
radioactive isotopes have too many or not enough electrons
Physical Chemistry
GeneralWhich character is the best example of an archetype?
A. A gravedigger who enjoys playing online video games all day
B. A nice old man who carves ritual masks out of exotic woods
C. A grandmother who suddenly decides to run for city council
D. A greedy executive who will stop at nothing to increase profits
Physical Chemistry
GeneralWater can dissolve many substances because -
F. it has a linear molecular shape
G. it is polar with a partial charge on each side of its molecule and has a bent molecular structure
H. it has the molecular formula H₂O
J. it has a nonpolar molecular structure
Physical Chemistry
GeneralSubstance A is mixed with water and donates 0.4% of its H+ ions. Which of the following BEST describes Substance A?
It is a weak acid and a poor conductor of electric current.
It is a weak base and a very good conductor of electric current.
It is a strong acid and a very good conductor of electric current.
It is a strong base and a very poor conductor of electric current.
Physical Chemistry
GeneralA sample of argon has a volume of 1.20 L at STP. If the temperature is increased to 23.0°C and the pressure is lowered to 0.800 atm, what will the new volume be, in L?
Physical Chemistry
GeneralA molecular cluster is formed from iron atoms and carbon monoxide (CO) molecules. If the molar mass of a cluster is 503.6 g/mol, and its empirical formula is Fe(CO)4, how many iron atoms does the cluster contain?
A) 1
B) 2
C) 3
D) 4
E) 5
Physical Chemistry
GeneralWhich of the following best describes limiting and excess reactants?
The amount of product obtained is determined by the excess reactant.
The amount of product obtained is determined by the limiting reactant.
The amount of product obtained is determined by the reactant with the largest mass.
The amount of product obtained is determined by the reactant with the smallest mass.
Physical Chemistry
GeneralBelow are the reactants of a single replacement (displacement) reaction:
2 NaBr(g) + Cl₂(aq) →
Which product(s) will this chemical reaction form?
2 NaBrCl
2 NaCl + Br₂
2 Na + 2 CIBr
2 Na+ Cl₂Br₂
Physical Chemistry
GeneralPotassium chlorate (KCIO3) decomposes into potassium chloride (KCI) and oxygen gas (O₂), as shown in the equation below:
KClO3(s) → KCl(s) + O₂(g)
Which set of coefficients balances the chemical equation for this reaction?
1, 1,3
2, 2, 2
2,2,3
2, 3, 6
Physical Chemistry
GeneralAccording to this reaction, how many moles of Cu are needed to react with 5.39 moles of AgNO3? Do not include units in your answer. Round to the tenths place or further.
Cu + 2 AgNO3 - Cu(NO3)2 + 2 Ag
Physical Chemistry
GeneralYou begin pouring sodium chloride into a glass of water. For a long time, the sodium chloride just dissolves in the water, but suddenly it begins to pile up at the bottom of the glass. Which statement is true?
The sodium chloride has increased the temperature of the water.
The sodium chloride has decreased the temperature of the water.
The water is unsaturated.
The water is saturated.
Physical Chemistry
GeneralIdentify the type(s) of intermolecular forces that are
present in the product that is produced from this
reaction.
Write the equilibrium-constant expression (Kp) for
the given equilibrium reaction, which is taking
place in the production of sulfur trioxide.
Consider the equilibrium reaction given above.
Consider an experiment where 1.25 mol sulfur
dioxide gas and 1.25 mol oxygen gas are combined
in a 1.00 L flask at 727 °C with a Kp value of 4.13
x 102. Calculate the concentrations of all the
reactant(s) and product(s) at equilibrium.
Physical Chemistry
GeneralAl2(SO3)3 + 6NaOH - 3Na₂SO3 + 2Al(OH)3
How many grams of sodium sulfite (Na₂SO3) can be made? (HINT: BE SURE TO USE YOUR LIMITING REAGENT FROM THE PREVIOUS QUESTION)
Round your answer to 2 decimal places. Do NOT give units in your answer.
Physical Chemistry
GeneralA baseball bat hits a baseball with a force of 100 Newtons. What is the force and its direction exerted by the ball on the bat?
A. 100 Newtons, same direction
B. 100 Newtons, opposite direction
C. 200 Newtons, same direction
D. 200 Newtons, opposite direction
Physical Chemistry
GeneralWrite a balanced chemical equation based on the following description: aqueous potassium phosphate reacts with aqueous nickel(II) bromide to produce solid nickel(II) phosphate and aqueous potassium bromide.
Physical Chemistry
GeneralCalculate the density of Iron, in g/mL if the mass of 13.55 g and the volume of 6.45 mL. Report your answer to the correct number of significant figures
A. 2.10077519 g/mL
B. 2.100 g/mL
C. 2.10 g/mL
D.2.11 g/mL
Physical Chemistry
General7.17 grams of aluminum acetate reacts with 3.21 grams of copper (II) phosphate. Predict the products, write the complete reaction equation, balance, and calculate the mass of the aqueous product.
Physical Chemistry
GeneralThe activity of chymotrypsin using N-acetyl-l-phenylalanine p-nitrophenyl ester as a substrate at pH = 7.0 was monitored spectroscopically in a 1 cm cuvette. What is the concentration of product produced if an absorbance of 0.6 is obtained at 415 nm, given a molar absorptivity of 15,000 L mol¹ cm¹?
There is not enough information to calculate the concentration.
40 uM
2.5 nM
9 mM
Physical Chemistry
GeneralWhen 1.491 grams of sucrose (Molar mass 342.3 g/mol) is burned in a bomb calorimeter, the temperature of the calorimeter increases from 22.41°C to 26.63°C. If the heat capacity of the calorimeter is 4.900 kJ/°C, what is the heat of combustion of sucrose, in kJ/mol?
Physical Chemistry
GeneralCalculate the theoretical yield in grams All, from the complete reaction of 113 grams 1₂ according to the following balanced chemical equation:
Physical Chemistry
GeneralAlpha Emission
One example is when a Uranium-238 nucleus decays, it produces a Thorium-234 nucleus and a Helium-4
nucleus. That Helium-4 nucleus is called an alpha particle(a). We use the symbol 4₂He.
These particles can be stopped by paper or skin.
Beta Emission
The second type of radioactive emission is beta particle emission. A beta particle(B) is a fast-moving
electron. We use the symbol º.1e.
These particles can be stopped by clothes or wood.
Gamma Emission
The third type of radioactive emission is gamma ray emission. A gamma ray is photon of light that has
the symbol oy.
This type of radiation is very high energy and dangerous to living (biological) things. It can be stopped by
lead or several feet of concrete.
26. Put the different types of emissions in order of weakest to strongest below:
Physical Chemistry
GeneralUsing the given reactions find the enthalpy for the decomposition of calcium carbonate into calcium oxide,
carbon, and oxygen gas in kJ.
Given: CaCO3 (s) → Cao (s) + CO₂ (g)
C(s) + O₂ (g) → CO₂ (g)
A. 215.5 kJ
B. 571.6 kJ
C. -215.4 kJ
CaCO3 (s) CaO (s) + C (s) + O₂ (g) AH = ? kJ
D. -571.6 kJ
Physical Chemistry
GeneralWhat mass, in grams, of precipitate will form when 303 g of nickel (II) nitrate reacts with excess rubidium phosphate? You will need a solubility table to correctly answer this question.
Physical Chemistry
GeneralWhich of the following is correct that represents the dissociation of ionic compound; Na₂SO4(aq).
A. Naz (aq) + SO4² (aq)
B. Na*(aq) + SO₂² (aq)
C. 2Na*(aq) + SO4² (aq)
D. Na*(aq) +2SO4² (aq)
Physical Chemistry
GeneralA 16.0 gram sample of iron was heated from 0°C to 35.0°C. It absorbed 246.4 Joules of energy as heat. What is the specific heat of this piece of iron?
A. 240 J/g°C
B. 3.67 J/gºC
C. 1.34 J/g °C
D. 0.44 J/g °C
Physical Chemistry
GeneralKOH(aq) + HC2H30 (aq) →KC2H30
2H³0₂(aq) + H₂O (1)
Calculate the molarity (M) of Acetic acid if the volume of acetic acid is 10.00 mL and moles of acetic acid is 0.002622 moles.
0.002622 M
2622 M
0.2622 M
0.0002622 M
Physical Chemistry
GeneralHow old is the Earth according to most Geologists?
4.6 billion years
4.6 thousand years
600 million years
4.6 million years
Physical Chemistry
GeneralThe chemical equation used for the experimental determination of iron in an unknown sample is,
5Fe2+ + MnO4 +8H+ +5Fe³+ + Mn2+ + 4H₂O
If the experimental data show that 0.0015 mol of MnO4 has been consumed in the reaction, how many mol of iron is in the sample?
A. 1.0 mol
B. 0.0030 mol
C. 0.0075 mol
D. 0.015 mol
E. 0.00030 mol
Physical Chemistry
GeneralA student has a sample of 1.76 moles of fluorine gas that is contained in a 22.1 L container at 256 K. What is the pressure of the sample? The ideal gas constant is 0.0821 L'atm/mol K. Round your answer to the nearest 0.01 and include units.
Physical Chemistry
GeneralWhich of the following would decrease the rate of solution when dissolving a solid in water?
A. Raise the temperature of the solution.
B. Crush the solid before mixing.
C. Stir the solution after mixing.
D. Use a single cube of solid.
Physical Chemistry
GeneralWhat is the formula for barium fluoride ?
What is the formula for sodium iodide ?
What is the formula for calcium oxide ?
Physical Chemistry
GeneralThe picture above shows a water wave hitting the beach. Which of the following is true about this process?
A. Neither energy nor water is transferred to the shore.
B. Water is transferred to the shore, but energy does not travel with the water.
C. Energy is transferred from the water to the shore, but the water does not travel with the energy
D. As energy transfers from the water to the shore, the water travels with the energy.
Physical Chemistry
GeneralWhich of the following would increase the rate of dissolution of a solid in a solution?
A. Cool the solid and the solution.
B. Cool only the solid.
C. Dry up the solvent.
D. Increase the temperature of the solvent.
Physical Chemistry
GeneralA student is studying a sample of neon in a container with a moveable piston (this means the container can change in size). If the sample in the container is initially at a pressure of 765.9 torr when the container has a volume of 76.7 mL, what is the pressure of the gas when the piston is moved so that the volume of the container becomes 131.8 mL? Round your answer to the nearest 0.01 and include units!
Physical Chemistry
GeneralWhat is the formula for the permanganate ion?
What is the name for CIO3?
What is the formula for the perchlorate ion?
Physical Chemistry
GeneralWhat is the systematic name for the coordination compound, [Cu(NH3)4]SO4.H₂O?
A. Tetraamminecopper(II) sulfate monohydrate
B. Aqueous Copper(II) sulfate tetraammonia
C. Tetraamminecopper(II) sulfate
D. Tetraamminecopper sulfate monohydrate
E. Tetraamminecopper(1) sulfate monohydrate
Physical Chemistry
GeneralAccording to Arrhenius' definition of base
they form a base when dissolved in water
they form hydronium ion when dissolved in water
they form hydroxide ion when dissolved in water
they form an acid when dissolved in water
Physical Chemistry
GeneralHuman skin emits radiation at a peak value of λ = 8.23 x 10-6 m.
What's the frequency of this radiation? (Hint: remember speed of light, c = 3.00 x 10³ m/s)
What type of electromagnetic waves are these?
How much energy in electron volts (eV) is carried by one quantum of these electromagnetic
waves?
Physical Chemistry
GeneralAn aircraft company is receiving complaints that passengers in their planes are receiving high levels of radiation from the Sun and other background radiation. sources. They respond by posting the following response online: Airline company: All of our aircraft are designed with state-of-the-art aluminum sheeting that blocks all radiation types from all sources. Thus, our passengers are not exposed to any dangerous levels of radiation inside of our aircraft. The Sun and other background sources produce alpha, beta, and gamma radiation, all of which enter Earths atmosphere. Based on all of the information, what statement best evaluates the airline companys claims?/span/p The aluminum sheeting will not be able to block any type of radiation. The airline company has made a correct claim about their aircraft and radiation. The aluminum sheeting will not block the high energy gamma radiation. Aluminum could block the weak background radiation, but not the Sun's radiation.
Physical Chemistry
GeneralWhat is the formula for sodium nitrite ?
What is the formula for barium sulfite ?
Physical Chemistry
GeneralIf you drew magnetic field lines for this bar magnet, which
statement would be true?
Arrows point away from both north and south.
Arrows point away from south and toward north.
Arrows point toward both north and south.
Arrows point away from north and toward south.
Physical Chemistry
GeneralWhat is the formula for sulfur hexafluoride ?
What is the formula for nitrogen monoxide ?
What is the formula for boron trifluoride ?