Exam 2 Intro to Chem

-the number of valence electrons __________ for elements in a group -the atomic size of atoms ________ going from top to bottom in a group -the atomic size of atoms _________ going from left to right across a period -the number of valence electrons ________ for atoms going from left to right across a period -the ionization energy ______ going from top to bottom in a group -the ionization energy _______ going from left to right across a period -metallic character ______ going from top to bottom in a group -metallic character ______ going from left to right across a period

-is the same -increases -decreases -increases -decreases -increases -increases -decreases

Combination of which of the following will result in a precipitation reaction? Select all that apply. -potassium chloride and lead(II) acetate -lithium sulfate and strontium chloride -potassium bromide and calcium sulfide -chromium(III) nitrate and potassium phosphate

-potassium chloride and lead(II) acetate -lithium sulfate and strontium chloride -chromium(III) nitrate and potassium phosphate

-An electronic sublevel that holds up to 2 electrons -A spherically shaped orbital -An electron sublevel that holds up to 14 electrons -An electron sublevel with 3 orbitals -An electron sublevel with 5 orbitals

-s sublevel -s sublevel -f sublevel -p sublevel -d sublevel

Manganese metal undergoes a single replacement reaction with sulfuric acid. What is the coefficient of hydrogen gas in the balanced equation that describes the process? Hint: the manganese ion in the product has a 2+ charge

1

Classify each of the following reactions: 1. CaCl2 * H2O(s) -> CaCl2(s) + H2O(g) 2. Na2O(s) + H2O(l) -> 2NaOH (aq) 3. P4(s) + 5O2(g) -> P4O10(s) 4. BaCl2(aq) + K2SO4(aq) -> BaSO4(s) + 2KCl(aq)

1. Decomposition 2. Combination 3. Combination 4. Double replacement

How many joules are there in a 255 calorie snack bar? A. 2.55 x 10^5 B. 1.07 x 10^6 C. 1.07 x 10^3 D. 6.09 x 10^4 E. none of these

1.07 x 10^3

What thickness (in cm) is the silicon block (density= 2.33 g/cm3) that is 2.87 cm wide and long necessary to react with 91.3 g of Cr2O3 by the reaction: 3Si(s) + 2Cr2O3(s) -> 3SiO2(s) + 4Cr (l)

1.3

Pentacarbonyliron (Fe(CO)5) reacts with phosphorus trifluoride (PF3) and hydrogen, releasing carbon monoxide: Fe(CO)5 + PF3 + H2 -> Fe(CO)2(PF3)2(H)2 + CO (not balanced) The reaction of 5.0 mol of Fe(CO)5, 8.0 mol of PF3 and 6.0 mol of H2 will release ________ mol of CO.

12

What is the sum of the coefficients in the equation that describes the reaction between solid cobalt (III) oxide and solid carbon to produce solid cobalt and gaseous carbon dioxide

12

The chemical reaction occurring during the discharge of a lead storage battery can be represented by the equation: Pb(s) + PbO2(s) + 2H2SO4(aq) -> 2PbSO4(s) + 2H2O (l) What is the mass of lead sulfate that would result from the complete reaction of 41.4 g of lead?

121 g

How many sublevels are contained in the second shell (n=2) of a given atom?

2

Write the balanced equation for the combustion of C5H10. What is the coefficient for C5H10?

2

Lead (II) carbonate decomposes to give lead (II) oxide and carbon dioxide. If the reaction yield is 95.7%, how many grams of lead (II) oxide will be produced by the decomposition of 2.50 g of lead (II) carbonate?

2.18

What is the mass of silver metal produced from 6.35 g of copper when copper reacts with excess silver nitrate in a single replacement reaction? _______ g (You can assume Cu forms a 2+ ion)

21.6

When 7.3 g of C3H8 burns in the presence of excess O2, ______ g of CO2 is produced.

22

Ammonia, an important source of fixed nitrogen that can be metabolized by plants, is produced by the Haber process in which nitrogen and hydrogen combine. N2 + 3H2(g) -> 2NH3(g) How many grams of nitrogen are needed to produce 325 grams of ammonia? _____g

268

Ethanol, C2H5OH, is made from fermenting grain and can be blended with gasoline to make "gasohol" If the combustion of "gasohol" produces carbon dioxide and water, what is the coefficient of oxygen in the balanced equation?

3

Gases emitted during volcanic activity often contain high concentrations of hydrogen sulfide and sulfur dioxide. These gases may react to produce deposits of sulfur according to the equation: 2H2S(g) + SO2(g) -> 3S(s) + 2H2O(g) For the complete reaction of 6.41 mol of hydrogen sulfide, what mass of sulfur is formed? _______ g

308

Aluminum chloride is formed via the combination reaction of aluminum and chlorine. What mass of aluminum chloride can be formed from the reaction of 7.5 kg of aluminum and 24.8 kg of chlorine? ____ kg

31

Dinitrogen tetroxide and hydrazine (N2H4) undergo a redox reaction in which nitrogen and water are formed as products. What mass of nitrogen could be produced when 50.0 g of dinitrogen tetroxide and 45.0 g of hydrozine are combined? Report your answer to the appropriate number of significant figures.

45.7

Automative air bags inflate when sodium azide decomposes explosively to its constituent elements: 2NaN3(s) -> 2Na(s) + 3N2(g) How many grams of sodium azide are required to produce 30.5 g of nitrogen? ____g

47

When calcium ionizes to form a calcium ion, electrons from the ____ sublevel are lost

4s

Water can be formed from the stoichiometric reaction of hydrogen and oxygen gases. A complete reaction of 5.0 g of O2 with excess hydrogen produces _____ g of H2O.

5.6

Phosphorus trichloride can be formed via a combination reaction from its elements. Phosphorus is often represented by its empirical formula, P, in chemical equations, as is carbon. If 12.39 g of phosphorus is combined with 42.54 g of chlorine, what mass of phosphorus trichloride could be formed?

54.9

Gold (III) nitrate undergoes a double replacement reaction with potassium chromate. What is the coefficient of potassium nitrate in the balanced equation?

6

Phosphoric acid and barium hydroxide participate in a double replacement reaction. What is the coefficient of water in the balanced equation?

6

In the reaction between glucose and oxygen, 10.0 g of glucose reacts and 7.50 L of carbon dioxide is formed. What is the percent yield if the density of CO2 is 1.26 g/L? C6H12O6(s) + 6O2(g) -> 6CO2(g) + 6H2O(l) _______%

64.5

How many grams of sodium fluoride (used in water fluoridation and manufacture of insecticides) are needed to form 485 g of sulfur tetrafluoride? _____g 3SCl2(g) + 4NaF(s) -> SF4(g) + S2Cl2(l) + 4NaCl(s)

756

-The sum of the coefficients when the equation below is balanced is ______ UO2(s) + HF(l) -> UF4(s) + H2O(l)

8

Determine the percent yield of a reaction that produces 28.65 g of Fe when 50.00 g of Fe2O3 react with excess Al in a single replacement reaction. _____%

81

The density of ethanol, C2H5OH, is 0.789 g/mL. How many mililiters of ethanol are needed to produce 15.0 g of CO2 via combustion reaction? _____ mL

9.95

What is the percent yield if 185 grams of SiO2 are made from328 g of Cr2O3 in the presence of excess silicon, according to the following equation? 3Si(s) + 2Cr2O3(s) -> 3SiO2 + 4Cr(l)

95.1

Lead(II) nitrate reacts with sodium iodide in order to precipitate lead(II) oxide. If 16.9 g of lead(II) nitrate reacts with 75.25 g sodium iodide to produce lead(II) iodide in an 85.0% yield, what is the actual yield of lead(II) iodide from the reaction?

98.36

A 55.0 g aluminum block initially at 27.5 °C absorbs 725 J of heat. What is the final temperature of the aluminum block? (Cs(Al)= 0.903 J/g* °C) A. 42.1 °C B. 15.2 °C C. 0.531 °C D. 830 °C E. 33.8 °C

A. 42.1 °C

When completing the orbital diagram for the element phosphorus, which of the following statements is correct? A. There are five electrons in the n=3 energy B. The 2p sublevel is not full C. There are electrons in the 3d sublevel D. There are no electrons in the 3s sublevel E. There is one unpaired electron in the 3p sublevel

A. There are five electrons in the n=3 energy

Given the following specific heats and that each sample had the same mass, which of the following materials would cool the slowest? A. ammonia, 4.70 J/(g*°C) B. water, 4.184 J/(g*°C) C. aluminum, 0.90 J/(g*°C) D. silver, 0.24 J/(g*°C) E. All cool at the same rate.

A. ammonia, 4.70 J/(g*°C)

The specific heat of a substance is the A. amount of heat required to change the temperature of a given mass B. amount of heat energy that is stored in chemical bonds C. amount of potential energy in a material that is released when a substance undergoes combustion and gives off heat D. temperature of which a compound starts to melt E. temperature at which a given mass's heat increases

A. amount of heat required to change the temperature of a given mass

The following reaction absorbs 393 kJ of heat for each mole of CO2 that reacts CO2(g) -> C(s) + O2(g) This reaction: A. is endothermic and has a positive value of q B. is exothermic and has a positive value of q C. is endothermic and has a negative value of q D. is exothermic and has a negative value of q

A. is endothermic and has a positive value of q

Which of the following changes represents a physical change, rather than evidence of a chemical reaction? A. when water and a yellow solution of antifreeze are mixed, the resulting solution is a lighter shade of yellow than the original antifreeze solution B. When concentrated HNO2 is placed in contact with copper metal, a brown gas is formed, the copper dissolves, and a green solution is formed C. When an egg is fried, the clear part becomes white, and the egg becomes a solid D. When a piece of zinc metal is placed in a blue solution of copper sulfate, the solution turns from blue to colorless, the zinc dissolves and copper metal is formed E. When solutions of AgNO3 and NaCl are mixed a white solid is formed

A. when water and a yellow solution of antifreeze are mixed, the resulting solution is a lighter shade of yellow than the original antifreeze solution

A solution of silver nitrate is mixed with a solution of sodium chloride, resulting in a precipitate of silver chloride and a solution of sodium nitrate. The class of this reaction is: A) combination B) double displacement reaction C) decomposition reaction D) single displacement reaction E) combustion reaction

B) double displacement reaction

Pioneers sometimes heated their coffee by placing an iron poker from the fire directly into their coffee. If a cup held 500mL of coffee at 18°C (Ccoffee= 4.184 h/g* °C), what would be the final temperature of the coffee when a 502 g iron poker at 800°C (Cfe= 0.450 J/g* °C) was placed in it? (Assume no heat is lost to the surrounding and no water vaporizes; densitycoffee= 1.00 g/mL) A. 102 °C B. 94.2 °C C. 92.4 °C D. 83.5 °C E. 98.6 °C

B. 94.2 °C

What reagent would distinguish between Ag+ and Fe3+? A. NaClO3 B. NaI C. NaNO3 D. NaOH E. none of these

B. NaI

Which has more total energy: a cup of boiling water at 100°C or a swimming pool of slightly cooler water at 90°C? A. The cup of boiling water at 100°C has more energy B. The swimming pool at 90°C has more energy C. They both have the same amount of energy because they are both made of water D. It is not possible to answer this question without knowing the ambient temperature surrounding each body of water

B. The swimming pool at 90°C has more energy

Which of the following processes is endothermic? A. burning gasoline in an internal combustion engine B. evaporation of perspiration on your skin C. burning wood in a fireplace D. condensing stream on a mirror E. hot coffee cooling down as it sits on the table

B. evaporation of perspiration on your skin

Natural gas, or methane, is an important fuel. Combustion of one mole of methane releases 802.3 kilojoules of energy. How much energy does that represent in kilocalories? A. 1.92 x 10^-1 kcal B. 1.92 x 10^2 kcal C. 3.36 x 10^3 kcal D. 1.92 x 10^5 kcal E. 3.36 x 10^6 kcal

B> 1.92 x 10^2 kcal

What is the specific heat of a metal object whose temperature increases by 3.0°C when 17.5 g of metal was heated with 38.5 J? A. 4.18 B. 0.15 C. 0.73 D. 1.4 E. none of these

C. 0.73

How much heat is required to raise the temperature of 1.00 gram of water from absolute zero, -273°C, to 100°C? A. 1.30 x 10^3 joules B. 373 joules C. 1.56 x 10^3 joules D. 2.26 x 10^3 joules

C. 1.56 x 10^3 joules

How many kilojoules are there in 95.0 Calories? A. 2.27 x 10^7 B. 3.97 x 10^-1 C. 397 D. 22.7 E. none of these

C. 397

A Snickers candy bar contains 280 calories, of which the fat content accounts for ____ calories. What is the energy of the fat content, in kJ? A. 5.0 x 10^-1 B. 29 kJ C. 5.0 x 10^2 D. 1.2 x 10^3 E. 5.0 x 10^5

C. 5.0 x 10^2

The number of joules needed to raise the temperature of 32 g of water from 12°C to 54°C is _____. A. 1300 J B. 1.3 J C. 5600 J D. 1700 J E. 130 J

C. 5600 J

What substance is the limiting reactant when 2.0 g of sulfur reacts with 3.0 g of oxygen and 4.0 g of sodium hydroxide according to the following chemical equation: 2S(s) + 3O2(g) + 4NaOH(aq) -> 2Na2SO4(aq) + 2H2O(l) A. S(s) B. O2(g) C. NaOH(aq) D. None of these substances is the limiting reactant

C. NaOH(aq)

Select the precipitate that forms when aqueous lead(II) nitrate reacts with aqueous sodium sulfate A. NaNO3 B. Na2NO3 C. PbSO4 D. Pb2SO4 E. there is no reaction

C. PbSO4

What is the correct complete ionic equation for the reaction between aqueous solutions of lead(II) nitrate and potassium iodide?

C. Pb^2+ + 2NO3 + 2K+ +2I -> PbI2(s) +2K+ + 2NO3

Which of the following best describes an exothermic reaction? A. Heat must be added to get the reaction to go B. The temperature of the surrounding decreases C. The potential energy of the reactants is greater than that of the surroundings. D. Matter is converted into energy E. Heat is absorbed by the reaction from the surroundings

C. The potential energy of the reactants is greater than that of the surroundings.

Aqueous potassium chloride will react with which one of the following? A. calcium nitrate B. sodium bromide C. lead nitrate D. barium nitrate E. sodium chloride

C. lead nitrate

How many joules are in 55.2 calories? A. 13.200 B. 55.200 C. 13.2 D. 231 E. none of these

D. 231

What is the final temperature when 20.0 g of water at 25°C is mixed with 30.0 g of water at 80°C? A. 35°C B. 42°C C. 53°C D. 58°C E. 70°C

D. 58°C

The balanced net ionic equation for the reaction, if any, that occurs when aqueous solutions of Na2Co3 and CaCl2 are mixed is

D. Ca^2+(aq) + CO3^2-(aq) -> CaCO3(s)

Would an aqueous solution of K2SO4 contain ions? If so, indicate the formulas of the ions in the solution. A. Yes. 2K+(aq) + S^2-(aq) + 4O^2-(aq) B. No, this substance would not form ions in solution C. Yes. 2K2^2+(aq) + SO4^2-(aq) D. Yes. 2K+(aq) + SO4^2-(aq) E. Yes. K2^2+(aq) + SO4^2-(aq)

D. Yes. 2K+(aq) + SO4^2-(aq)

Select the correct name and chemical formula for the precipitate, if any, that forms when aqueous solutions of copper(III) chloride and sodium carbonate are combined. A. sodium chloride NaCl B. copper(II) carbonate Cu2CO3 C. copper(I) carbonate CuCO3 D. copper (II) carbonate CuCO3 E. there is no reaction

D. copper (II) carbonate CuCO3

Galena is the ore from which experimental lead is extracted. In the first step of the extraction process, galena is heated in air to form lead (II) oxide. 2PbS(s) + 3O2(g) -> 2SO2(g) ΔH= -827.4 kJ What mass of galena is converted to lead oxide if 975 kJ of heat are liberated? A. 203 g B. 282 g C. 406 g D. 478 g E. 564 g

E. 564 g

Give the net ionic equation for the reaction (if any) that occurs when aqueous solutions of K2S and Fe(NO3)2 are mixed.

Fe^2+ (aq) + S^2- (aq) -> FeS(s)

-The number of electrons in the third shell of a sodium atom is ____ -The number of electrons in a neutral chlorine atom is ____ -The number of electrons in the 3p sublevel of a phosphorus atom is ____ -The number of electrons in the 3s sublevel of a sulfur atom is ____ -The number of neutrons in a neutral hydrogen atom is ____

-1 -17 -3 -2 -0

-The maximum number of electrons that may reside in the n=4 energy level is ____ -The maximum number of electrons that may reside in the n=2 energy level is ____ -The maximum number of electrons that can occupy a single d orbital is ____ -The maximum number of electrons that can occupy the 3p sublevel is -An s sublevel can hold a maximum of _____ electrons

-32 -8 -2 -6 -2

Which of the following is/are impossible -2p -3f -4d^11 -3s^3 -2d

-3f -4d^11 -3s^3 -2d

-The number of sublevels in the 4th principal level is ____ -The number of sublevels in the 2nd principal level is ____ -The lowest principal shell that can contain a d sublevel is ____ -The 5d sublevel can hold a maximum of _____ electrons -The number of electrons that can be accommodated by a 5f orbital is _____

-4 -2 -3 -10 -2

-number of orbitals in a 3d sublevel -number of electrons in a 3d sublevel -number of electrons in a 3d orbital -number of unpaired electrons possible in a 3d sublevel -number of unpaired electrons possible in a 3d orbital

-5 -10 -2 -5 -1

Which of the following equations are balanced? Select all that apply -CH4 + 2O2 -> CO2 + H2O -BaCl2 + H2SO4 -> 2HCl + BaSO4 -2 CH4H10O + 13O2 -> 8CO2 + 10H2O -AgNO3 + 2NH4Cl -> AgCl + (NH4)2NO3 -HNO3 + NaHSO3 -> NaNO3 + H2O + SO2

-BaCl2 + H2SO4 -> 2HCl + BaSO4 -HNO3 + NaHSO3 -> NaNO3 + H2O + SO2

Which of the following combinations of reactants are not likely to result in the formation of a precipitate? Select all that apply: -H2SO3 + Li^+ +Cl^- -> -Pb^2+ + 2NO3^- + 2Na^+ + 2OH^- -> -Li^+ + Br^- + Pb^2+ + NO3^- -> -Ag^+ + Br^- + NO3^- + K^+ -> -Na^+ .+ Cl^- + NO3^- +K^+ . ->

-H2SO3 + Li^+ +Cl^- -> -Na^+ .+ Cl^- + NO3^- +K^+ . ->

The elements with their valence electrons in the same principal shell, of those below, are: -Lithium -Sodium -Nitrogen -Fluorine -Argon

-Lithium -Nitrogen -Fluorine

Which ions(s) would NOT be spectator ions when aqueous solutions of lead(II) nitrate and potassium iodide are combined? Select all that apply: -Pb^2+ -NO3- K+ -I- -there is no reaction

-Pb^2+ -I-

Which changes are chemical reactions? Select all that apply -Propane forms a flame and emits heat as it burns -Acetone feels cold as it evaporates from the skin -Bubbling is observed when potassium carbonate and hydrochloric acid solutions are mixed -Heat is felt when a warm object is placed on your hand

-Propane forms a flame and emits heat as it burns -Bubbling is observed when potassium carbonate and hydrochloric acid solutions are mixed

The expected products of the reaction between zinc metal and hydrochloric acid are (select all that apply): -ZnCl2 -ZnCl -H2 -Cl2 -H2O

-ZnCl2 -H2

Classify each of the following reactions: -2H2O2(aq) -> 2H2O(l) + O2(g) -2Na(s) + 2H2O (l) -> 2NaOh(aq) + H2(g) -2NaCl(l) -> 2Na(l) + Cl2(g) -H2(g) + Cl2(g) -> 2HCl (g)

-decomposition -single replacement -decomposition -combination