### SAT Chemistry Subject Test - Practice Test 4

##
**SAT Chemistry Subject Test - Practice Test 4**

**Note:**For all questions involving solutions and/or chemical equations, assume that the system is in water unless otherwise stated.

**Reminder:**You may not use a calculator on these tests.

The following symbols have the meanings listed unless otherwise noted.

H = enthalpy

M = molar

n = number of moles

P = pressure

R = molar gas constant

S = entropy

T = temperature

V = volume

atm = atmosphere

g = gram(s)

J = joules(s)

kJ = kilojoules

L = liter(s)

mL = milliliter(s)

mm = millimeter(s)

mol = mole(s)

V = volt(s)

**PART A**

**Directions:**Every set of the given lettered choices below refers to the numbered statements or formulas immediately following it. Choose the one lettered choice that best fits each statement or formula and then fill in the corresponding oval on the answer sheet. Each choice may be used once, more than once, or not at all in each set.

**Questions 1-3:**

**refer to the following graphs:**

**1.**The graph that best shows the relationship of gas volume to temperature, with pressure held constant

**2.**The graph that best shows the relationship of gas volume to pressure, with temperature held constant

**3.**The graph that best shows the relationship of the number of grams of a solid that are soluble in 100 grams of H

_{2}0 at varying temperatures if the solubility begins at a small quantity and increases at a slow, steady pace as the temperature is increased

**Questions 4-7:**

**(A)**A molecule

**(B)**A mixture of compounds

**(C)**An isotope

**(D)**An isomer

**(E)**An acid salt

**4.**The simplest unit of water that retains its properties

**5.**A commercial cake mix

**6.**An atom with the same number of protons as another atom of the same element but a different number of neutrons

**7.**Classification of Ca(HCO

_{3})

_{2}

**Questions 8-10:**

**(A)**1

**(B)**6

**(C)**9

**(D)**10

**(E)**14

**8.**The atomic number of an atom with an electron dot arrangement similiar to

**9.**The number of atoms represented in the formula Na

_{2}CO

_{3}

**10.**The number that represents the most acid pH

**Questions 11-14:**

**(A)**Density

**(B)**Equilibrium constant

**(C)**Molar mass

**(D)**Freezing point

**(E)**Molarity

**11.**Can be expressed in moles of solute per liter of solution

**12.**Can be expressed in grams per liter of a gas

**13.**Will NOT be affected by changes in temperature and pressure

**14.**At STP, can be used to determine the molecular mass of a pure gas

**Questions 15-18:**

**(A)**Buffer

**(B)**Indicator

**(C)**Arrhenius acid

**(D)**Arrhenius base

**(E)**Neutral condition

**15.**Resists a rapid change of pH

**16.**Exhibits different colors in acidic and basic solutions

**17.**At 25°C, the aqueous solution has a pH < 7.

**18.**At 25°C, the aqueous solution has a pH > 7.

**Questions 19-23:**

**(A)**O

_{2}

**(B)**SO

_{2}

**(C)**CO

**(D)**CO

_{2}

**(E)**O

_{2}

**19.**In the stratosphere, screens out a large fraction of the ultraviolet rays of the sun

**20.**Is a product of the incomplete combustion of hydrocarbons

**21.**A gas produced by the heating of potassium chlorate

**22.**A gas that is slightly soluble in water and gives a weakly acid solution

**23.**The gas with the slowest effusion rate

**PART B**

ON THE ACTUAL CHEMISTRY TEST, THE FOLLOWING TYPE OF QUESTION MUST BE ANSWERED ON A SPECIAL SECTION (LABELED “CHEMISTRY”) AT THE LOWER LEFT-HAND CORNER OF PAGE 2 OF YOUR ANSWER SHEET. THESE QUESTIONS WILL BE NUMBERED BEGINNING WITH 101 AND MUST BE ANSWERED ACCORDING TO THE FOLLOWING DIRECTIONS.

**Directions:**Every question below contains two statements, I in the left-hand column and II in the right-hand column. For each question, decide if statement I is true or false and if statement li is true or false and fill in the corresponding T or F ovals on your answer sheet. *Fill in oval CE only if statement II is a correct explanation of statement I.

**Sample Answer Grid:**

CHEMISTRY * Fill in oval CE only if II is a correct explanation of I.

**PART C**

**Directions:**Every question or incomplete statement below is followed by five suggested answers or completions. Choose the one that is best in each case and then fill in the corresponding oval on the answer sheet.

**Question 24**:

In this graphic representation of a chemical reaction, which arrow depicts the activation energy of the forward reaction?

**(A)**A

**(B)**B (Q C

**(D)**D

**(E)**E

**Question 25**:

How many liters (STP) of O

_{2}can be produced by completely decomposing 2.00 moles of KClO

_{3}?

**(A)**11.2

**(B)**22.4

**(C)**33.6

**(D)**44.8

**(E)**67.2

**Question 26**:

Which of the following statements is true?

**(A)**A catalyst cannot lower the activation energy.

**(B)**A catalyst can lower the activation energy.

**(C)**A catalyst affects only the activation energy of the forward reaction.

**(D)**A catalyst affects only the activation energy of the reverse reaction.

**(E)**A catalyst is permanently changed after the activation energy is reached.

**Question 27**:

Which of the following is the correct structural representation of sodium?

**Question 28**:

If the molecular mass of NH

_{3}is 17, what is the density of this compound at STP?

**(A)**0.25 g/L

**(B)**0.76 g/L

**(C)**1.52 g/L

**(D)**3.04 g/L

**(E)**9.11 g/L

**Question 29**:

Which bond(s) is (are) ionic?

I. H—Cl(g)

II. S—Cl(g)

III. Cs—F(s)

**(A)**I only

**(B)**III only

**(C)**I and II only

**(D)**II and III only

**(E)**I, II, and III

**Question 30**:

Aromatic hydrocarbons are represented by which of the following?

**(A)**I only

**(B)**III only

**(C)**I and II only

**(D)**II and III only

**(E)**I, II, and III

**Question 31**:

According to placement in the Periodic Table, which statement(s) regarding the first ionization energies of certain elements should be true?

I. Li has a higher value than Na.

II. K has a higher value than Cs.

III. Na has a higher value than Al.

**(A)**I only

**(B)**III only

**(C)**I and II only

**(D)**II and III only

**(E)**I, II, and III

**Question 32**:

Redox reactions include which of the following?

Na

_{2}S(aq) + PbCl

_{2}(aq) → NaCl(s) + PbS(s)

CH

_{4}(g) + O

_{2}(g) → C0

_{2}(g) + H

_{2}O(l)

H

_{2}(g) + O

_{2}(g) → H

_{2}O(l)

**(A)**I only

**(B)**III only

**(C)**I rind II only

**(D)**II and III only

**(E)**I, II, and III

**Questions 33-35:**

**What is the apparent oxidation state (number) of the underlined element in the compound**

**33.**KHCO

_{3}?

**(A)**+1

**(B)**+2

**(C)**+3

**(D)**+4

**(E)**+5

**34**: MgSO

_{4}?

**(A)**+1

**(B)**-1

**(C)**+2

**(D)**-2

**(E)**+3

**35**: CO

_{2}?

**(A)**+2

**(B)**-2

**(C)**+4

**(D)**-4

**(E)**+5

**Question 36**:

An atom with an electron configuration of 1s

^{2}2s

^{2}2p

^{6}3s

^{2}3p

^{4}will probably exhibit which oxidation state?

**(A)**+2

**(B)**-2

**(C)**+3

**(D)**-3

**(E)**+5

**Question 37**:

In the Lewis dot structure X:, what is the predictable oxidation number?

**(A)**+1

**(B)**-1

**(C)**+2

**(D)**-2

**(E)**+3

**Questions 38-40:**

**(A)**Balance

**(B)**Barometer

**(C)**Condenser CD) Funnel

**(E)**Pipette

**38.**Commonly used in the laboratory to transfer an exact volume of liquid from one container to another

**39.**Commonly used in the laboratory in a distillation setup

**40.**Commonly used in the laboratory in a filtration setup

**Question 41**:

If you collected hydrogen gas by the displacement of water and under the conditions shown:

which of the following would give you the pressure of the hydrogen in the bottle?

**(A)**730. mm - 40.8 mm

**(B)**730. mm - 30.0 mm

**(C)**730. mm - 30.0 mm/13.6 + 40.8 mm

**(D)**730. mm - 30.0 mm/13.6 - 40.8 mm

**(E)**730. mm - 40.8 mm/13.6 - 30.0 mm

**Question 42**:

What occurs when a reaction is at equilibrium and more reactant is added to the container?

**(A)**The equilibrium remains unchanged.

**(B)**The forward reaction rate increases.

**(C)**The reverse reaction rate increases.

**(D)**The forward reaction rate decreases.

**(E)**The reverse reaction rate decreases.

**Question 43**:

How much heat energy is released when 8 grams of hydrogen are burned? The thermal equation is 2H

_{2}(g) + O

_{2}(g) —> 2H

_{2}O(g) + 483.6 kj.

**(A)**241.8 kj

**(B)**483.6 kj

**(C)**967.2 kj

**(D)**1,934 kj

**(E)**3,869 kj

**Question 44**:

Would the reaction shown below be spontaneous? Why or why not?

ZnCl

_{2}(aq) + Au(s) -> Zn(s) + AuCl

_{3}(aq)

**(A)**Yes, gold is more active than zinc.

**(B)**No, gold is less active than zinc.

**(C)**Yes, gold is less active than zinc.

**(D)**No, gold is more active than zinc.

**(E)**No, gold and zinc have the same activity.

**Question 45**:

Four moles of electrons (4 × 6.02 × 10

^{23 }electrons) would electroplate how many grams of silver from a silver nitrate solution?

**(A)**108

**(B)**216

**(C)**324

**(D)**432

**(E)**540

**Question 46**:

A 5.0 M solution of HCl has how many moles of H

^{+}ion in 1 liter?

**(A)**0.50

**(B)**1.0

**(C)**2.0

**(D)**2.5

**(E)**5.0

**Question 47**:

What is the K

_{sp}for silver acetate if a saturated solution contains 2 × 10

^{-3}moles of silver ion/liter of solution?

(A) 2 × 10

^{-3}

(B) 2 × 10

^{-6}

(C) 4 × 10

^{-3}

(D) 4 × 10

^{-6}

(E) 4 × 10

^{6}

**Question 48**:

The following data were obtained for H

_{2}O and H

_{2}S:

What is the best explanation for the variation of physical properties between these two compounds?

**(A)**The H

_{2}S has stronger bonds between molecules.

**(B)**The H

_{2}O has a great deal of hydrogen bonding.

**(C)**The bond angles differ by about 15°.

**(D)**The formula mass is of prime importance.

**(E)**The oxygen atom has a smaller radius and thus cannot bump into other molecules as often as the sulfur.

**Question 49**:

What is the pOH of a solution that has 0. 00001 mole of H

_{3}O

^{+}/liter of solution?

**(A)**2

**(B)**3

**(C)**4

**(D)**5

**(E)**9

**Question 50**:

How many grams of sulfur are present in 1 mole of H

_{2}SO

_{4}?

**(A)**2

**(B)**32

**(C)**49

**(D)**64

**(E)**98

**Question 51**:

What is the approximate mass, in grams, of 1 liter of nitrous oxide, N

_{2}O, at STP?

**(A)**1

**(B)**2

**(C)**11.2

**(D)**22

**(E)**44

**Question 52**:

If the simplest formula of a substance is CH

_{2}and its molecular mass is 56, what is its true formula?

**(A)**CH

_{2 }

**(B)**C

_{2}H

_{4 }

**(C)**C

_{3}H

_{4 }

**(D)**C

_{4}H

_{8 }

**(E)**C

_{5}H

_{10}

**Questions 53 and 54:**

**refer to the following dia¬grams of two methods of collecting gases:**

**53.**Method 1 is best suited to collect

**(A)**a gas denser than air

**(B)**a gas less dense than air

**(C)**a gas that is insoluble in water

**(D)**a gas that is soluble in water

**(E)**a gas that has a distinct color

**54.**Which of these gases, because of its density and solubility, should be collected by Method 2?

**(A)**NH

_{3 }

**(B)**H

_{2 }

**(C)**HCL

**(D)**CO

_{2 }

**(E)**He

________________________________________________

**Question 55**:

What is the molar mass of CaCO

_{3}?

**(A)**68 g/mol

**(B)**75 g/mol

**(C)**82 g/mol

**(D)**100 g/mol

**(E)**116 g/mol

**Question 56**:

What volume, in liters, will be occupied at STP by 4 grams of H

_{2}?

**(A)**11.2

**(B)**22.4

**(C)**33.6

**(D)**44.8

**(E)**56.0

**Question 57**:

How many moles of KOH are needed to neutralize 196 grams of sulfuric acid? (H

_{2}SO

_{4}= 98 amu)

**(A)**1.0

**(B)**1.5

**(C)**2.0

**(D)**4.0

**(E)**6.0

**Question 58**:

What volume, in liters, of NH

_{3}(g) is produced when 22.4 liters of N

_{2}(g) are made to combine completely with a sufficient quantity of H

_{2}(g) under appropriate conditions?

**(A)**11.2

**(B)**22.4

**(C)**44.8

**(D)**67.2

**(E)**89.6

**Question 59**:

What volume, in liters, of SO

_{2}will result from the complete burning of 64 grams of sulfur?

**(A)**2.00

**(B)**11.2

**(C)**44.8

**(D)**126

**(E)**158

**Question 60**:

The amount of energy required to melt 5.00 grams of ice at 0°C would also heat 1 gram of water at 4°C to what condition?

(Heat of fusion = 80 cal/g or 3.34 × 10

^{2}J/g; heat of vaporization = 540 cal/g or 2.26 × 10

^{3}J/g)

**(A)**water at 90°C

**(B)**water at 100°C

**(C)**steam at 100°C

**(D)**Part of the water would be vaporized tosteam.

**(E)**All of the water would be vaporized to steam.

**Question 61**:

How many moles of electrons are needed to electroplate a deposit of 0.5 mole of silver from a silver nitrate solution?

**(A)**0.5

**(B)**1

**(C)**27

**(D)**54

**(E)**108

**Question 62**:

All of the following statements about carbon dioxide are true EXCEPT:

**(A)**It can be prepared by the action of acid on CaCO

_{3}.

**(B)**It is used in fire extinguishers.

**(C)**It dissolves slightly in water at room temperature.

**(D)**It sublimes rather than melts at 20°C and 1 atm pressure.

**(E)**It is a product of photosynthesis in plants.

**Question 63**:

Three moles of H

_{2}and 3 moles of I

_{2}are introduced into a liter box at a temperature of 490°C. What will the K expression be for this reaction? (K = 45.9)

**Question 64**:

If the following reaction has achieved equilibrium in a closed system:

N

_{2}O

_{4}(g) ⇌ 2 NO

_{2}(g)

which of the following is (are) increased by decreasing the size of the container?

The value of K

II. The concentration of N

_{2}O

_{4}(g)

III. The rate of the reverse reaction

**(A)**I only

**(B)**III only

**(C)**I and II only

**(D)**II and III only

**(E)**I, II, and III

**Question 65**:

**Question 66**:

How many grams of NaCl will be needed to make 100. milliliters of 2 M solution?

**(A)**5.85

**(B)**11.7

**(C)**29.2

**(D)**58.5

**(E)**117

**Question 67**:

How many grams of H

_{2}SO

_{4}are in 1,000. grams of a 10.% solution? (1 mol of H

_{2}SO

_{4}= 98 g)

**(A)**1.0

**(B)**9.8

**(C)**10.

**(D)**98

**(E)**100.

**Question 68**:

If 1 mole of ethyl alcohol in 1,000 grams of water depresses the freezing point by 1.86° Celsius, what will be the freezing point of a solution of 1 mole of ethyl alcohol in 500 grams of water?

**(A)**-0.93°C

**(B)**-1.86°C

**(C)**-2.79°C

**(D)**-3.72°C

**(E)**-5.58°C

**Question 69**:

Which nuclear reaction shows the release of a beta particle?

**ANSWER KEY**

**Practice Test 4**

**ANSWERS EXPLAINED**

**Answer 1:**

**(A)**The volume of a gas increases as temperature increases provided that pressure remains constant. This is a direct proportion. Heating a balloon is a good example.

**Answer 2:**

**(C)**The volume of a gas decreases as the pressure is increased provided that the temperature is held constant. This is shown by the inversely proportional curve in (C). Pressure increase on a closed cylinder is a good example.

**Answer 3:**

**(E)**The graph shows that there is a starting quantity in solution, and a slight positive slope to the right indicates a directly proportional change in the solubility as temperature rises.

**Answer 4:**

**(A)**This is the definition of any molecule.

**Answer 5:**

**(B)**A commercial cake mix is a mixture of ingredients.

**Answer 6:**

**(C)**This is the definition of an isotope.

**Answer 7:**

**(E)**An acid salt contains one or more H atoms in the salt formula separating a positive ion and the hydrogen-bearing negative ion. For example, Na

_{2}SO

_{4}is a normal salt and NaHSO

_{4}is an acid salt because of the presence of H in the hydrogen sulfate ion. In Ca(HCO

_{3})

_{2}, the same is true. This is classified as an acid salt.

**Answer 8:**

**(C)**An atom with atomic number 9 would have a 2,7 electron configuration, which matches the outer energy level of iodine.

**Answer 9:**

**(B)**There are 2 Na, 1 C, and 3 O, which add to 6 atoms.

**Answer 10:**

**(A)**pH from 0 to 6 is acid, 7 neutral, 8 to 14 basic. Most acid is 1.

**Answer 11:**

**(E)**Molarity is defined as moles of solute/liter of solution.

**Answer 12:**

**(A)**Gas densities can be expressed in grams/liter.

**Answer 13:**

**(C)**Molar mass is not affected by pressure and temperature.

**Answer 14:**

**(A)**If the density of a gas is known, the mass of 1 L can be multiplied by 22.4 to find the molecular mass because 1 mol occupies 22.4 L at STP.

**Answer 15:**

**(A)**Buffers resist changes in pH.

**Answer 16:**

**(B)**Color change is the function of indicators.

**Answer 17:**

**(C)**On the pH scale, from 0 to 6 is acid and 7 is neutral:

**Answer 18:**

**(D)**On the pH scale, from 8 to 14 is basic.

**Answer 19:**

**(E)**The ozone (O

_{3}) in the stratosphere absorbs ultraviolet rays from the sun.

**Answer 20:**

**(C)**When hydrocarbons containing C and H do not have enough oxygen to combust with O

_{2}(g) completely, the product will be CO, carbon monoxide.

**Answer 21:**

**(A)**2KClO

_{3}-> 2KCl + 3O

_{2}(g) is the reaction that occurs.

**Answer 22:**

**(D)**CO

_{2}is slightly soluble in water, forming carbonic acid, H

_{2}CO

_{3}, which is a weak acid.

**Answer 23:**

**(B)**SO

_{2}has the highest molar mass.

**Answer 101:**

**(T, F)**The assertion is true, but the degree of motion of gas molecules is directly related to the temperature.

**Answer 102:**

**(T, T, CE)**Assertion and reason are true; an electron can be treated as either an elec-tromagnetic wave or a bundle of negative charge.

**Answer 103:**

**(T, T, CE)**A homologous series increases each member by a constant number of carbons and hydrogens. Examples are the alkane, alkene, and alkyne series, which each increase the chain by a CH

_{2}group. The reason is true and does explain the assertion.

**Answer 104:**

**(T, F)**The nuclear charge of an active metallic ion is greater than that of the electron cloud. The reason is false.

**Answer 105:**

**(T, T, CE)**A negative heat of formation indicates that the reaction is exothermic and the enthalpy change is negative.

**Answer 106:**

**(T, T, CE)**Water is a polar molecule because there is unequal sharing of bonding electrons.

**Answer 107:**

**(T, T, CE)**This is a function of a catalyst—to speed up a reaction without permanently changing itself. Assertion and reason are true.

**Answer 108:**

**(F, T)**The Cu is losing electrons and thus being oxidized; the assertion is false. It is furnishing electrons and thus is a reducing agent; the reason is true.

**Answer 109:**

**(F, T)**H

_{2}= 2, He = 4 (molecular mass); then inversely √4: √2 = √2:√2 is the rate of diffusion of hydrogen to helium. The assertion is false; the reason, true.

**Answer 110:**

**(T, T, CE)**Since the gas is being heated at constant pressure, it expands. The tempera¬tures are converted to kelvins (K) by adding 273° to the Celsius readings. The fraction 373/273must be and this will increase the volume.

**Answer 111:**

**(F,T)**Gibbs free energy is useful in indicating the conditions under which a chemical reaction will occur. Therefore, the equation can be used to predict the spontaneity of a reaction. Change in enthalpy and change in entropy are both part of the Gibbs free energy equation: ΔG = ΔH - TΔS.

**Answer 112:**

**(F, F)**Water is 1/9 hydrogen and 8/9 oxygen by weight. Both assertion and reason are false.

**Answer 113:**

**(T, T, CE)**Four grams of ice would require 4 × 80 cal/g = 320 cal or 4 × 3.34 × 10

^{2}J/g = 1.34 × 10

^{3}J to melt the ice.

**Answer 114:**

**(F, T)**The reaction is: 2H

_{2}+ O

_{2 }→ 2H

_{2}O. The coefficients of this gaseous reaction show

that 2 liters of hydrogen react with 1 liter of oxygen. This would leave 1 liter of unreacted oxygen. The limiting factor is the hydrogen.

**Answer 115:**

**(T,F)**The reason why water is a good solvent is false.

**Answer 116:**

**(T, T, CE)**The density of a gas at STP is found by dividing the molecular mass by 22.4 L. NH

_{3}has a gram-molecular mass of N = 14 + 3H = 3 or a total of 17 g. The gram-molecular mass of Ar is 40 g. The density of each can be found by dividing by 22.4 L, but obviously the density of the ammonia will be smaller.

**Answer 24:**

**(C)**The energy necessary to get the reaction started, which is the activation energy, is shown at C.

**Answer 25:**

**(E)**2KClO

_{3}-> 2KCl + 3O

_{2}(g) shows that 2.00 mol of KClO

_{3}yield 3 mol of O

_{2}.

**Answer 26:**

**(B)**A catalyst can speed up a reaction by lowering the activation energy needed to start the reaction and then keep it going.

**Answer 27:**

**(E)**The atomic number gives the number of protons in the nucleus and the total number of electrons. The mass number indicates the total number of protons and neu¬trons in the nucleus—for Na, 23 (11 protons + 12 neutrons).

**Answer 28:**

**(B)**Density =Mass/Volume. For gases this is expressed as grams per liter. Since 1 molar mass of a gas occupies 22.4 L, 17 g/22.4 L = 0.76 g/L.

**Answer 29:**

**(B)**Choice III is made up of elements from extreme sides of the Periodic Table and will therefore form ionic bonds.

**Answer 30:**

**(B)**Only III is a ring hydrocarbon of the aromatic series.

**Answer 31:**

**(C)**Since Li is higher in Group 1 than Na, and K is higher than Cs, they have smaller radii and hence higher ionization energies. A1 is to the right of Na and therefore has a higher ionization energy.

**Answer 32:**

**(D)**Only II and III are redox reactions. The first reaction is a precipitation reaction. PbS is the precipitate, and the oxidation states of the substances in the reaction are not changing. The second equation is a combustion reaction. The oxidation states of carbon and oxygen change from -4 to +4 and 0 to -2, respectively. The third reaction is a syn¬thesis reaction. The oxidation states of hydrogen and oxygen change from 0 to +1 and 0 to -2, respectively.

**Answer 33:**

**(A)**These answers are based on the fact that

**Answer 34:**

**(C)**the total of the assigned oxidation numbers times their occurrence for all the atoms in a

**Answer 35:**

**(C)**compound is zero.

**Answer 36:**

**(B)**This orbital configuration shows 6 electrons in the third energy level. The atom would like to gain 2e

^{-}to fill the 3p and thereby gain a -2 oxidation number.

**Answer 37:**

**(C)**With this structure, the atom would tend to lose these electrons and get a +2 charge.

**Answer 38:**

**(E)**The pipette is used to transfer liquid from one container to another.

**Answer 39:**

**(C)**The condenser tube is used in distillation.

**Answer 40:**

**(D)**The funnel is used to hold the filter paper.

**Answer 41:**

**(E)**The pressure in the bottle would be less than atmospheric pressure by the Hg equivalent height of the 30 mm of water above the level in the collecting pan. This is calculated as 40.8 mm water/(13.6 mm water/1 mm Hg) and must be subtracted from atmospheric pressure. The other adjustment is to subtract the vapor pressure of water that is in the hydrogen gas since it was collected over water. This pressure is given as 30.0 mm Hg. Subtracting each of these from 730.mm Hg, the given atmospheric pres¬sure, you have 730. mm - 40.8 mm/13.6 - 30.0 mm.

**Answer 42:**

(B) The equilibrium shifts in the direction that tends to relieve the stress and thus regain equilibrium.

**Answer 43:**

(C) The thermal reaction shows 2 mol of hydrogen reacting, or 4 g. Therefore, 8 g would release twice the amount of energy:

2 × 483.6 kj = 967.2 kj.

**Answer 44:**

(B) The reaction would not be spontaneous because gold is less active than zinc. This could be determined by looking at the activity series for metals. Gold is the least active of all the metals and will not replace another metal in a compound spontaneously.

**Answer 45:**

(D) Since Ag

^{+}+ le

^{-}-> Ag°, 1 mol of electrons yields 1 mol of silver; 1 mol silver = 6.02 × 10

^{23}atoms, and 4 × 108 g/mol = 432 g

**Answer 46:**

(E) 5.0 M = 5.0 mol/L, and since HCl ionizes completely there would be 5.0 mol of H

^{+}and 5.0 mol of Cl

^{-}ions.

**Answer 47:**

(D) K

_{sp}= [Ag

^{+}][C

_{2}H

_{3}O

_{2}

^{-}l = [2 ×10

^{-}

^{3}] [2 × 10

^{-}

^{3}]

(Since AgC

_{2}H

_{3}O

_{2}⇌ Ag

^{+}+ C

_{2}H

_{3}O

_{2}

^{-}

the silver ion and acetate ion concentrations are equal.)

K

_{sp}= 4 ×10

^{-6}

**Answer 48:**

(B) It is the explanation for the observed high boiling point and high freezing point of water compared with hydrogen sulfide.

**Answer 49:**

(E) pH = -log[H

^{+}]

= -log[10

^{-}

^{5}] = -[-5] = 5

Since pH + pOH = 14, pOH = 14 - 5 = 9.

**Answer 50:**

(B) 1 mol H

_{2}SO

_{4}contains 1 molar mass of sulfur, that is, 32 g.

**Answer 51:**

(B) N

_{2}O = 44 g/mol

(2 × 14 + 16 = 44)

1 mol of a gas occupies 22.4 L, so 44 g/22.4 L = 1.99 g/L.

**Answer 52:**

(D) CH

_{2}= 14

(12 + 2 = 14 molecular mass)

56 ÷ 14 = 4

Then 4 × CH

_{2}= C

_{4}H

_{8}

**Answer 53:**

(C) Only insoluble gases can be collected in this way.

**Answer 54:**

(C) HCl is very soluble in water and denser than air, so it is suited to the No. 2 collec¬tion method.

**Answer 55:**

(D) Ca = 40

C = 12

30 = 48

_________

100 g/mol

**Answer 56:**

(D) Gram-molecular mass of H

_{2}is 2 g. 4 g is 2 mol, and each mole occupies 22.4 L. 2 x 22.4 = 44.8 L. x mol 196 g

**Answer 57:**

(D)

**Answer 58:**

(C)

**Answer 59:**

**Answer 60:**

(D) 5.00 g ice to water = 5.00 x 80 cal = 400 cal. 1 g at 4° can go to 100°C as water and absorb 1 cal/°C. Then 400 cal - (100° - 4°) = 400 - 96 = 304 cal. 304 cal can change 304 cal/540 Cal or 0.56 g of water to steam. There obviously is not enough heat to vaporize all the water. If done in joules, 5.00 g of ice to water = 5.00 × 3.34 × 10

^{2}g/J = 1.67 × 10

^{3}J.

1 g at 4°C to 100°C = Δtemp = 96°

96° × 4.18 J/g/°C = 17.3 J/g = 1.73 × 10

^{1}J = 0.0173 × 10

^{3}J

1.67 × 10

^{3}J - 0.0173 × 10

^{3}J = 1.65 × 10

^{3}J left for vaporization. Since 1 g requires 2.26 × 10

^{3}J for vaporization, (D) is the answer.

**Answer 61:**

(A) Since Ag

^{+}gains le

^{-}to become Ag°, 0.5 mol requires 0.5 mol of electrons.

**Answer 62:**

(E) CO

_{2}is a reactant in photosynthesis, not a product. The reaction is

**Answer 63:**

**Answer 64:**

(D) In a closed system, decreasing the size of the container will cause the pressure to increase. When pressure is applied to an equilibrium involving gases, the reaction that lowers the pressure by decreasing the number of molecules will increase in rate. In this reaction, the rate of the reverse reaction, in which 2 molecules are decreased to 1, increases, thus reducing pressure while also increasing the concentration of N

_{2}O

_{4}. Thus, II and III are true.

**Answer 65:**

(A) This is Rutherford’s famous artificial transmutation experiment, done in 1919.

**Answer 66:**

**Answer 67:**

(E) Percent is by mass, so 10.% is 0.10 x 1,000. g or 100. g.

**Answer 68:**

(D) Since colligative properties, like freezing point, are related to the concentration of the solute particles and since the decrease in volume of the solution causes the concentration of the solution to be doubled, the colligative effect will be doubled.

**Answer 69:**

(C) The nuclear reactions shown release: (A) a neutron, (B) an alpha particle, (C) a beta particle, (D) no particles, (E) a positron.

**CALCULATING YOUR SCORE**

Your score on Practice Test 4 can now be computed manually. The actual test will be scored

by machine, but the same method is used to arrive at the raw score. You get one point for f each correct answer. For each wrong answer, you lose one-fourth of a point. Questions that you omit or that have more than one answer are not counted. On your answer sheet mark all correct answers with a “C” and all incorrect answers with an “X.”

**Determining Your Raw Test Score**

Total the number of correct answers you have recorded on your answer sheet. It should be the same as the total of all the numbers you place in the block in the lower left corner of each area of the Subject Area summary in the next section.

**A.**Enter the total number of correct answers here:_________

Now count the number of wrong answers you recorded on your answer sheet.

**B.**Enter the total number of wrong answers here:__________

Multiply the number of wrong answers in B by 0.25.

**C.**Enter that product here:__________

Subtract the result in C from the total number of right answers in A.

**D.**Enter the result of your subtraction here:_________

**E.**Round the result in D to the nearest whole number: _________.

This is your raw test score.

**Conversion of Raw Scores to Scaled Scores**

Your raw score is converted by the College Board into a scaled score. The College Board scores range from 200 to 800. This conversion is done to ensure that a score earned on any edition . of a particular SAT Subject Test in Chemistry is comparable to the same scaled score earned on any other edition of the same test. Because some editions of the tests may be slighdy easier or more difficult than others, scaled scores are adjusted so that they indicate the same level of performance regardless of the edition of the test taken and the ability of the group that takes it. Consequently, a specific raw score on one edition of a particular test will not necessarily translate to the same scaled score on another edition of the same test.

Because the practice tests in this book have no large population of scores with which they can be scaled, scaled scores cannot be determined.

Results from previous SAT Chemistry tests appear to indicate that the conversion of raw scores to scaled scores GENERALLY follows this pattern:

Note that this scale provides only a general idea of what a raw score may translate into on a scaled score range of 800-200. Scaling on every test is usually slightly different. Some students who had taken the SAT Subject Test in Chemistry after using this book had reported that they have scored slightly higher on the SAT test than on the practice tests in this book. They all reported that preparing well for the test paid off in a better score!

**DIAGNOSING YOUR NEEDS**

After taking Practice Test 4, check your answers against the correct ones. Then fill in the chart below.

In the space under each question number, place a check if you answered that question correctly.

**Example______________________________________________**

If your answer to question 5 was correct, place a check in the appropriate box.

Next, total the check marks for each section and insert the number in the designated block. Now do the arithmetic indicated, and insert your percent for each area.

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