Chemistry Spring Final Exam

Calcium hypochlorite, Ca(OCl)2, is a bleaching agent produced from sodium hydroxide, calcium hydroxide, and chlorine. Sodium chloride and water are also produced in the reaction. What is the missing coefficient that will balance the chemical equation?

2

The first step in constructing a Lewis dot structure for a molecule is to determine how many valence electrons are in all of the atoms contained in the molecule. How many total valence electrons are contained in the atoms of a molecule of butane, C4H10?

26 e-

Which of the following must not be split up when writing net ionic equations? A molecular substances, liquids, and solids B solids, liquids, and ionic substances C ionic substances, soluble substances, and gases D soluble substances, molecular substances, and solids

A molecular substances, liquids, and solids

Between which two atoms are ionic bonds most likely to form? (Draw electron-dot structures to help you decide.) A) K and F B) O and O C) C and H D) N and O

A) K and F ionic bonds are between a nonmetal and a metal

at what pressure would this gas occupy a volume of 5.0L? A. 0.4 atm B. 0.33 atm C. 2.0 atm D. 0.5 atm

A. 0.4 atm

Which mole ratio for the equation 6Li + N2→2Li3N is incorrect? A. 6 mol Li/ 2 mol N2 B. 1 mol N2 /6 mol Li C. 2 mol Li3N/1 mol N2 D. 2 mol Li3N/ 6 mol Li

A. 6 mol Li/ 2 mol N2

Which of the following molecules contains a double bond? A. COCl2 B. C2H6 C. CF4 D. SF

A. COCl2

A precipitation of iron(III) hydroxide is produced by reacting an aqueous solution of iron(III) chloride with an aqueous solution of sodium hydroxide. Which is the correct balanced chemical equation?

A. FeCl3 + 3NaOH -> Fe(OH)3 (s) + 3NaCl (s)

How is the hydroxide part of a chemical formula for the bases in the table expressed?

A. OH

When the temperature of a gas is increased within a closed container, pressure increases due to which of the following? A. The frequency of collisions between molecules and the container walls decreases. B. The frequency of collisions between molecules and the container walls increases. C. The spaces between the molecules of gas decrease. D. The gas turns into a liquid.

A. The frequency of collisions between molecules and the container walls decreases.

2C(s) + O2(g) = 2CO the equilibrium constant is-

A. [CO]2/[O2]

Which of the following conditions will favor a spontaneous reaction? A. an increase in entropy and a decrease in enthalpy B. an increase in both entropy and enthalpy C. a decrease in both entropy and enthalpy D. a decrease in entropy and an increase in enthalpy

A. an increase in entropy and a decrease in enthalpy

The kinetic-molecular theory states that ideal gas molecules — A. are in constant, rapid, random motion B. slow down as temperature increases C. exert forces of attraction and repulsion on each other D. have high densities compared with liquids and solids

A. are in constant, rapid, random motion

Identify the salt that forms when a solution of H2SO4is titrated with a solution of Ca(OH)2. A. calcium sulfate B. calcium hydroxide C. calcium oxide D. calcium phosphate

A. calcium sulfate

Which one of the acids in the table is an organic acid?

A. citric acid

To balance a chemical equation, you may adjust the A. coefficients. B. subscripts. C. formulas of the products. D. either the coefficients or the subscripts.

A. coefficients

Increasing the temperature of a substance — A. increases its kinetic energy B. increases its potential energy C. increases its specific heat D. makes the molecules move more slowly

A. increases its kinetic energy

Molarity is expressed in units of A. moles of solute per liter of solution. B. liters of solution per mole of solute. C. moles of solute per liter of solvent. D. liters of solvent per mole of solute

A. moles of solute per liter of solution

Which of the following properties is a common property of acids? A. pH values < 7 B. insoluble in water C. does not conduct electricity D. does not react with metals

A. pH values < 7

Which change can cause the value of the equilibrium constant to change

A. temperature

Two metals of equal mass but different specific heats absorb the same amount of heat. Which metal undergoes the smaller change in temperature? A. the metal with the higher specific heat B. the metal with the lower specific heat C. Both undergo the same change in temperature. D. cannot determine from the information given

A. the metal with the higher specific heat

A rate law relates — A. reaction rate and temperature B. reaction rate and concentration C. temperature and concentration D. energy and concentration

B reaction rate and concentration

What mass of NaOH is contained in 2.5 L of a 0.010 M solution? A. 0.010 g B. 1.0 g C. 2.5 g D. 0.40 g

B. 1.0 g

A saturated solution can become supersaturated under which of the following conditions? A. It contains electrolytes. B. A heated saturated solution is allowed to cool. C. More solvent is added. D. More solute is added.

B. A heated saturated solution is allowed to cool.

Water boils at 100°C. Ethanol boils at 78.5°C. Which of the following statements is true? A. Water has the higher vapor pressure at 78.5°C. B. Ethanol has the higher vapor pressure at 78.5°C. C. Both have the same vapor pressure at 78.5°C. D. Vapor pressure is not related to boiling point

B. Ethanol has the higher vapor pressure at 78.5°C

The "phlogiston theory" was the idea that combus-tion depended on the presence of a substance called phlogiston. Phlogiston was colorless, odor-less, and, apparently, massless, but without it, a substance would not burn. Why might it be inaccu-rate to call phlogiston a scientific theory?

B. It was difficult to test, because phlogiston was undetectable.

Which of the following formula-name pairs below is written correctly? A. Na(OH)1= sodium hydroxide B. NH4OH = ammonium hydroxide C. Sr(OH)2= strontium(II) hydroxide D. Cu(OH)2= copper(I) hydroxide

B. NH4OH = ammonium hydroxide

At a constant pressure, the following reaction is exothermic: 2NO2(g) --> N2O4(g) Which of the following statements is true about the reaction (as written)? A. The reaction is always spontaneous. B. The reaction is spontaneous at low temperatures but not at high temperatures. C. The reaction is spontaneous at high temperatures but not at low temperatures. D. The reaction is never spontaneous.

B. The reaction is spontaneous at low temperatures but not at high temperatures.

Which of the following statements is true about the reaction 2F2 + 2H2O → 4HF + O2? A. Two grams of O2 are produced when 2 g of F2react with 2 g of H2O. B. Two moles of HF are produced when 1 mol of F2reacts with 1 mol of H2O. C. For every 2 mol O2 produced, 6 mol HF are produced. D. For every 1 mol H2O that reacts, 2 mol O2 are produced.

B. Two moles of HF are produced when 1 mol of F2reacts with 1 mol of H2O.

The Kw value for water can be affected by — A. dissolving a salt in the solution B. changes in temperature C . changes in the hydroxide ion concentration D. the presence of a strong acid

B. changes in temperature

Which is the correct name for the base CuOH2? A. copper hydroxide B. copper(II) hydroxide C. copper(I) hydroxide D. copper hydroxide(I)

B. copper(II) hydroxide

exothermic reaction reached equilibrium, then increasing the temperature will-

B. favor the reverse reaction

Identify the conditions in which a spontaneous chemical reaction is expected in all cases. A. if ∆H is negative and ∆S is negative B. if ∆H is negative and ∆S is positive C. if ∆H is positive and ∆S is negative D. if ∆H is positive and ∆S is positive

B. if ∆H is negative and ∆S is positive

Pure liquids boil at higher temperatures under high pressures than they do under low pressures, because — A. liquid molecules are closer together at higher pressures B. it takes a higher temperature for the vapor pressure to equal the higher external pressure C. vapor molecules are farther apart at higher pressures D. the vapor diffuses more rapidly at higher pressures

B. it takes a higher temperature for the vapor pressure to equal the higher external pressure

The Lewis structure of HCN contains A. one double bond and one single bond. B. one triple bond and one single bond C. two single bonds. D. two double bonds

B. one triple bond and one single bond

Identify which of the following substances would be soluble in water in all cases. A lead(II) iodide B sodium nitrate C silver carbonate D barium sulfate

B. sodium nitrate

what point is the equivalence point on the graph?

C

Which of the following is the best representation of the precipitation reaction that occurs when aqueous solutions of sodium carbonate and calcium chloride are mixed? A Na+(aq) + Cl-(aq) → 2NaCl(s) B Ca2+(aq) + CO32- (aq) → CaCO3(s) C 2Na+(aq) + CO32- (aq) + Ca2+(aq) + 2Cl-(aq) → CaCO3(s) + 2NaCl(s) D No precipitation reaction occurs.

C 2Na+(aq) + CO32- (aq) + Ca2+(aq) + 2Cl-(aq) → CaCO3(s) + 2NaCl(s)

Which of the following statements accurately describes precipitates and precipitation reactions? A Dissolve means the same thing as dissociate. B Ionize means the same thing as dissociate C A substance can dissolve without dissociating. D Electrolytes form whenever solids are added to water.

C A substance can dissolve without dissociating.

A certain reaction is zero order in reactant A and second order in reactant B. What happens to the reaction rate when the concentrations of both reactants are doubled? A The reaction rate remains the same. B The reaction rate increases by a factor of two. C The reaction rate increases by a factor of four. D The reaction rate increases by a factor of eight.

C The reaction rate increases by a factor of four.

A neutral aqueous solution — A has a 7.0 M H3O+concentration B contains neither hydronium ions nor hydroxide ions C has an equal number of hydronium ions and hydroxide ions D none of the above

C has an equal number of hydronium ions and hydroxide ions

Which of the following is not incorporated into a net ionic equation? A solids B liquids C spectator ions D precipitates

C spectator ions

Which is the balanced chemical equation for the following formula equation: (NH4)2S = NH3 + H2S

C. (NH4)2S = 2NH3 + H2S

Gas A and gas B (both unreactive) are allowed to mix. The total pressure is found to be 3.50 atm. If gas B was measured initially at 1.25 atm, what is the partial pressure of gas A? A. 4.75 atm B. -2.25 atm C. 2.25 atm D. 1.25 atm

C. 2.25 atm

Analyze the reaction of solid magnesium and water. Which pair of reactants and products in the table below represents the correct balanced equation for the reaction?

C. 3- Mg (s) + H2O (l) --> Mg(OH)2(aq) + H2 (g)

Estimate the boiling point of ethanol at an applied (external) pressure of 200 torr. A. 10°C B. 40°C C. 50°C D. 80°C

C. 50°C

Which of the following statements is true for the reaction below?HF(aq) +HPO42-(aq) ⟵⟶F-(aq) + H2PO4- (aq) A. HF is the base. B. HPO42- is the acid. C. F- is the conjugate base. D. H2PO4-is the conjugate base.

C. F- is the conjugate base

Identify the precipitate in the following reaction:Ca(OH)2(aq) + FeCl3(aq) → A Ca(OH)2 B FeCl3 C Fe(OH)3 D CaCl2

C. Fe(OH)3

Identify the reaction in which a precipitate occurs. A NaOH + HCl → B NaNO3+ KI → C MgBr2+ AgNO3→ D None of the above form precipitates.

C. MgBr2 + AgNO3 ->

Which of the following represents the correct Lewis dot structure for sodium chloride?

C. Na+ +[:..Cl..:]-

How is the oxide part of a chemical formula for the bases in the table expressed?

C. O

Lewis structures use dots to depict valence electrons. For the following elements, what pattern in the corresponding Lewis dot structures can you identify? lead (Pb) antimony (Sb) sulfur (S) chlorine (Cl) A. The dot structure for each contains the same number of outer electrons. B. The number of outer electrons increases by 2 for each element. C. The number of outer electrons increases by 1 for each element. D. The number of outer electrons corresponds to the total number of electrons in each element

C. The number of outer electrons increases by 1 for each element.

f the pH of a solution of the strong base NaOH is known, which property of the solution can be calculated? A. molar concentration B. [OH−] C. [H3O+] D. all of the above

C. [H3O+]

Which of the following is not a typical property of solids? A. very low melting point B. high density C. easily compressible D. low rate of diffusion

C. easily compressible

A chemical reaction is in equilibrium when-

C. forward and reverse reaction rates are equal

Which of the following processes has a negative ∆S? A. evaporating 1 mol of a liquid B. raising the temperature of 1 L of water from 295 K to 350K C. freezing of 1 mol of a liquid D. none of the above

C. freezing of 1 mol of a liquid

Two liquids are likely to be immiscible- A.both have polar molecules. B. both have nonpolar molecules. C. one is polar and the other is nonpolar. D. one is water and the other is methyl alcohol, CH3OH.

C. one is polar and the other is nonpolar (water and oil)

Identify the correct pairing of term and definition. A. enthalpy—temperature B. endothermic—reaction in which energy is released C. specific heat—amount of energy required to raise 1 g of a substance 1 degree Celsius (or 1 Kelvin) D. joule—the unit that measures temperature

C. specific heat—amount of energy required to raise 1 g of a substance 1 degree Celsius (or 1 Kelvin)

If a collision between molecules is very gentle, the molecules are — A more likely to be oriented favorably B less likely to be oriented favorably C likely to react D likely to rebound without reacting

D likely to rebound without reacting

In a graph of how energy changes with reaction progress, the activated complex appears at the — A left end of the curve B right end of the curve C bottom of the curve D peak of the curve

D peak of the curve

From what you know of the properties of water, estimate which value best corresponds to average atmospheric pressure. A. 200 torr B. 460 torr C. 600 torr D. 760 torr

D. 760 torr

Which of the explanations below describes why catalysts can increase reaction rates? A. Adding a catalyst adds more molecules. B. Adding a catalyst adds heat to the reaction. C. Adding a catalyst adds electricity to the reaction. D. Adding a catalyst provides an alternate reaction mechanism having a lower potential-energy barrier between reactants and products

D. Adding a catalyst provides an alternate reaction mechanism having a lower potential-energy barrier between reactants and products

Determine the missing reactant for the following combustion reaction: 2 ______ + 15O2→14CO2+6H2O. A. C14H12 B. C14H12O4 C. C7H6 D. C7H6O2

D. C7H6O2

How does the potential energy of the activated complex compare with the energies of the reactants and products? A. It is less than both the energy of the reactants and the energy of the products. B. It is less than the energy of the reactants but greater than the energy of the products. C. It is greater than the energy of the reactants but less than the energy of the products. D. It is greater than both the energy of the reactants and the energy of the products.

D. It is greater than both the energy of the reactants and the energy of the products.

Which one of the following statements is false? A. Gases are generally more soluble in water under high pressures than under low pressures. B. As temperature increases, the solubilities of solids in water increase. C. Water dissolves many ionic solutes because of its ability to hydrate ions in solution. D. Many solids dissolve more quickly in a cold solvent than in a warm solvent.

D. Many solids dissolve more quickly in a cold solvent than in a warm solvent

A transition structure that results from an effective energetic collision between reactants is the — A. order of the reaction B. rate law C. overall reaction D. activated complex

D. activated complex

Dalton's law of partial pressure explains why, when gases are collected over water, A. water vapor forms that mixes with the other gases. B. water vapor pressure must be subtracted to determine the final pressure of the other gases. C. the gas pressures add up to a total pressure. D. all of the above

D. all of the above

Distilled water contains- A. H2O B. H3O+ C. OH- D. all of the above

D. all of the above

According to the law of conservation of mass, the total mass of the reacting substances is A. always more than the total mass of the products. B. always less than the total mass of the products. C. sometimes more and sometimes less than the total mass of the products. D. always equal to the total mass of the products

D. always equal to the total mass of the products

The solubility of a gas in a liquid would be increased by A. the addition of an electrolyte. B. the addition of an emulsifier. C. agitation of the solution. D. an increase in its partial pressure

D. an increase in its partial pressure

Which of the following types of compounds is most likely to be a strong electrolyte? A. a polar compound B. a nonpolar compound C. a covalent compound D. an ionic compound

D. an ionic compound

Le Chateliers principle

D. chemical equilibrium response to reduce applied stress

Which of the following correctly illustrates the Lewis structure for a covalent compound?

H D) H-C- H H covalent= two nonmetals

A gas has a volume of 5 L at 120 K. What is its volume (in liters) at 100 K? (Round to nearest thousandth.)

V1/V2 = T1/T2 5L/V2 = 120K/ 100K V2= 4.167 L

5.0 L of a gas goes from 1.0 atm to 1.3 atm. Calculate the final volume of this gas. A. 6.5 L B. 0.26 L C. 4.1 L D. 3.8 L

V1P1=V2P2 (5.0 L) (1.0 atm) = (V2) (1.3 atm) V2= 3.8 L D. 3.8 L

What is the volume of this gas at 4.0 atm pressure? A. 0.68 L B. 1.0 L C. 0.5 L D. 4.0 L

c. 0.5 L

How many hydrogen atoms in CH3COOH can be ionized?

one

What is the pH of a 0.0010 M solution of HNO3? A. 1.0 B. 3.0 C. 4.0 D. 5.0

pH= -log(H+) pH= -log(0.0010 M) pH=B. 3.0

The hydroxide ion concentration in a solution is 1.6 × 10-11 M. What is the pOH of the solution? (Express your answer to two decimal places.)

pOH= -log(OH-) pOH= -log(1.6 x 10-11 M) pOH= 10.80

The pH of a solution is 6.32. What is the pOH? A. 6.32 B. 4.8 × 10-7 C. 7.68 D. 2.1 × 10-8

pOH= 14 - 6.32 C. 7.68

Silicon dioxide reacts with carbon to produce silicon carbide and carbon monoxide. A chemist performs this reaction in the lab and writes her data in the table shown here Reactants Products SiO2 : 25 g SiC(s) : 15 g C (s) : 15g CO(g) : 22g what is the percent yield for CO?

percent yield for CO = 95%

Calculate the volume of 12.0 g of helium at 100°C and 1.2 atm. A. 0.013 L B. 76.5 L C. 7,750 L D. 56.0 L

pv=nrt (1.2 atm) (v) = (0.082 atm*L/mole*K) (373 K) (3 moles) v= 76.5 L B. 76.5 L