sat subject test_ chemistry_ diagnostic test - learningpod

Practice Questions

SAT Subject Test: Chemistry: Diagnostic Test

ANSW ER (Choose the correct answer)




POD

Takes into account various isotopes of an atom1.

Atomic massAAtomic numberBAtomic radiusCElectronegativityDIonization potentialE

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Determines how electron density is shared w hen an atom forms a bond2.


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Average distance betw een the nucleus and the outermost electron3.


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Number of protons in an element4.


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Energy required to remove an electron5.


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Has a f illed 4 p orbital6.

NaAFeB

C $MRbD

E $Bby Kaplan Test Prep

All of its electrons are paired in this ion7.

NaAFeB

C $MRbD


Electron configuration is,

1 2 2 3 3 3 4

8.

/

/

,

/

,

/

NaAFeB

C $MRbD


Cannot be further broken dow n by chemical means9.

CationAInert GasBCrystalCAnionDElementE

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Ionic species w ith a positive charge10.


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Has an octet of valence electrons11.


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Defined by the number of protons12.


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Apparatus used to measure the heat absorbed or released by a reaction13.

CentrifugeABarometerBBalanceCCalorimeterDBatteryE

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Apparatus used to measure atmospheric pressure14.


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Apparatus used to measure w eight15.


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Apparatus used to sediment particles in suspension16.


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The energy of a system available to do w ork17.

Gibbs free energyAHeat of formationBSpecif ic heatCHeinsenberg uncertainty principleDHeat of vaporizationE

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Heat required to raise one unit mass of a substance by 1 degree Celsius18.


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Heat absorbed or released during production of a substance from elements in their standard states19.


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Which one of the follow ing Forms a strong base w hen dissolved in w ater?20.

NaOHACsClBHBrC

COOHD $)E

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Which one of the follow ing Forms a w eak acid w hen dissolved in w ater?21.

NaOHACsClBHBrC

COOHD $)E

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Which one of the follow ing Forms a strong acid w hen dissolved in w ater?22.

NaOHACsClBHBrC

COOHD $)E

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Which one of the follow ing Forms an ionic solution w ith a neutral pH w hen dissolved in w ater?23.

NaOHACsClBHBrC

COOHD $)E

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What is the formal charge on the nitrogen atom in ?24.

-1A+1B0C+2D+3E

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What volume of a 1 M solution of hydrochloric acid is required to neutralize 80 mL of a 0.5 M NaOH solution?25.

320 mLA160 mLB80 mLC40 mLD20 mLE

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Which of the follow ing w ould be classif ied as a strong electrolyte?26.

Benzoic acidAWaterBHydrofluoric acidCPotassium chlorideDGlucoseE

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Which atom has an ionic radius that is larger than its atomic radius?27.

NaAKBMgCCaDClE

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The basic structure of crystalline substances is called28.

unit cellAmoleculeBlatticeCgeodeDmatrixE

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The oxidation state of nitrogen is most negative in w hich of the follow ing compounds?29.

A B C D E

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An insulated tube w ith a movable piston at one end had 500 J of heat added to it. If , during the experiment, the piston moves

and does 75 J of w ork on the atmosphere, w hat is the change in energy of the tube system?

30.

575 JA500 JB425 JC75 JD425 JE

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The reaction of NaOH and in w ater goes to completion because31.

it is a neutralization reactionAw ater is a strong electrolyteBsodium sulfate quickly precipitatesCa volatile product is formedDsulfuric acid is a very strong acidE

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Which of the follow ing w ould be different in a ground state and an excited state neon atom?32.

The number of neutronsAThe number of electronsBThe atomic w eightCThe electronic configurationDEverything w ould remain the same.E

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The of Mg in w ater is 1.2 x . If the concentration in an acid solution is 1.2 x mol/L, w hat is

the pH at w hich Mg just begins to precipitate?

33.

TQ

0)

#

3A4B5C11D12E

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Which of the follow ing states has the highest average translational kinetic energy?34.

SolidALiquidBGasCColloidDNone of the aboveE

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Which of the follow ing w ill favor the melting of ice in a closed container if all other parameters are kept constant?35.

Adding w ater w ith a temperature of CA Low ering the temperature below CB Low ering the pressureCRaising the pressureDDecreasing the amount of iceE

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Which of the follow ing has the most polar bond?36.

N-OACHBCCCHFDNone of the bonds are polar.E

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The rate law expression for the reaction

+ 3 2N

37.

can be represented by rate = A < >

< >

can be represented by rate = k B can be represented by rate =

C ' < >

< >

can be represented by rate = D ' < >

cannot be determined from the information givenEby Kaplan Test Prep

100 mL of 10 N is diluted to 800 mL. What is the molarity of the dilute acid solution?38.

16/10 MA8/10 MB10/8 MC10/12 MD5/8 ME

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Which of the follow ing molecules contains both ionic and covalent bonds?39.

A Mg B $M

C

D E

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Gas A is at C and gas B is at C. Both gases are at 1 atmosphere. What is the ratio of the volume of 1 mole of gas A to

1 mole of gas B?

40.

1:1A2:3B3:2C303:293D606:293E

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How w ill the equilibrium of the follow ing reaction be affected if more chlorine is added?

( g ) ( g ) + ( g )

41.

1$M

1$M

$M

It w ill be shifted to the right.AIt w ill be shifted to the left.BIt w ill be unaffected.CThe effect on the equilibrium cannot be determined w ithout more information.DMore w ill be produced.E 1$M

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After balancing the equation

... ( aq ) + ... ( aq ) + ... ( aq ) ... ( l ) + ...

the ratio of to is

42.

#S

.

#S

#S

.

1:5A1:3B1:2C1:1D2:3E

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What mass of sodium carbonate, (formula w eight = 106 amu), is needed to make 120 mL of a 1.5 M solution?43.

295 gA9.5 gB19 gC589 gD19,000 gE

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Equimolar amounts of hydrogen and oxygen gas, at the same temperature, are released into a large container. The ratio of the

rate of diffusion of the hydrogen molecules to that of the molecules of oxygen w ould be

44.

256:1A16:1B1:16C4:1D1:4E

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What does X represent in the follow ing nuclear reaction?

+ + X

45.

"M

)F

particleA DPositronB

particleC CNeutronD

rayE Eby Kaplan Test Prep

When chromium metal is used to form , the oxidation state of chromium changes from46.

.

0 to 4A3 to 6B2 to 6C0 to 6D2 to 4E

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Electron density studies have revealed that X and Y have an equal number of electrons. Which of the follow ing could X and Y

be?

47.

and KA $B and HeB

Cl and FC and D

None of the aboveEby Kaplan Test Prep





All halogens have similar reactivity because48.

they have the same number of protonsAthey have the same number of electronsBthey have similar outer shell electron configurationsCthey have valence electrons w ith the same quantum numbersDthey have the same number of neutronsE

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and have the same49. $M

atomic w eightAelectronic configurationBionization potentialCnumber of protons and neutronsDatomic radiusE

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Which of the follow ing has the largest ionic radius?50.

A /BB C .HD "ME $M

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When the follow ing reaction is balanced, w hat is the net ionic charge on the right side of the equation?

... + ... + ... ... + ... + ...

51.

.O

'F

.O

'F

+5A+7B+10C+17DThe net ionic charge on either side must be zero.E

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Question below refer to the follow ing equation.

...Ag + ...

What is the sum of the coeff icients once the equation is balanced?

52.

"H

/)

1A2B3C4D5E

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...Ag + ...

How many moles of Ag + are required to produce 11 moles of ammonia?

53.

"H

/)

1A2B5.5C11D22E

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...Ag + ...

What is the percent composition by w eight of Ag in Ag ?

54.

"H

/)

4.2A19.7B76.1C80.3D95.8E

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If 88 g of and 160 g of are allow ed to react maximally to form and , how many grams of w ill be

formed?

55.

$0

$0

33A66B132C264DNone of the aboveE

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A 200 mL flask contains oxygen at 200 mm Hg, and a 300 mL flask contains neon at 100 mm Hg. The tw o f lasks are connected

so that each gas f ills their combined volumes. Assuming no change in temperature, w hat is the partial pressure of neon in the

final mixture?

56.

60 mm HgA80 mm HgB100 mm HgC150 mm HgD200 mm HgE

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What is the value of Z in the beta decay reaction below ?

+

57.

$P

!

25A26B27C28D29E

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Question below refer to the follow ing experimental setups.

Which of the follow ing experimental setups w ill complete the circuit?

58.

II onlyAIII onlyBIII and IVCII, III, and IVDI, II, III, and IVE

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What types of bonds are found in solid NaCl?

59.

Van der WaalsAIonicBCovalentCHydrogenDHydrophobicE

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What w ould happen if the electrodes w ere put in a saturated solution of glucose dissolved in w ater?

60.

Light bulb w ould glow .ALight bulb w ould remain dark.BApparatus w ould combust.CGlucose molecules w ould dissociate.DNone of the aboveE

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Which of the follow ing statements correctly characterizes a galvanic cell?

I. Oxidation occurs at the anode, w hich is negative.

II. Oxidation occurs at the anode, w hich is positive.

III. Reduction occurs at the cathode, w hich is positive.

61.

II onlyAIII onlyBI and IIICI, II, and IIIDII and IIIE

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The heat of combustion of gaseous ammonia is 81 kcal/mole. How much heat is evolved in the reaction of 34 grams of ammonia

w ith excess oxygen?

62.

40.5 kcalA60.3 kcalB75.8 kcalC81 kcalD162 kcalE

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When there are tw o electrons in the 3 s sublevel,63.

they must occupy different orbitalsAthe Heisenberg uncertainty principle predicts that they must periodically jump to the 3 p sublevelBthe oxidation state of the atom must be 2+Cthey must have opposite spinsDthey are oppositely chargedE

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In order to make a buffer solution, a w eak monoprotic acid could be added to64.

another acidAanother baseBits conjugate baseCits conjugate acidDa strong baseE

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How w ill the equilibrium of the follow ing reaction be affected if the temperature is increased?

( g ) + 3 ( g ) 2 ( g ) = -30kJ/mol

65.

9

It w ill be shifted to the right.AIt w ill be shifted to the left.BIt w ill be unaffected.CThe effect on the equilibrium cannot be determined w ithout more information.DNone of the aboveE

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For a sample of an ideal gas of f ixed w eight and at a f ixed temperature,

I. the volume varies directly w ith the pressure exerted on it

II. the volume varies inversely w ith the pressure exerted on it

III. the pressure varies directly w ith the density of the gas

66.

I onlyAII onlyBIII onlyCI and IIDII and IIIE

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When 200 g of Mg is added to 1 kg of w ater, w hat is the molality of the solution?67. $M

200/(24 + 71)A0.200/(24 + 71)B0.2(24 + 71)C0.200D200E

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How many moles of w ater are formed by a mixture of 100 grams of and 100 grams of ? (Assume the reaction goes to

completion.)

68.

100/32 + 100/64A100 + 2(100/32)B2(100/32)C100(100/32)D200(100/32)E

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An oxide of arsenic contains 65.2% arsenic by w eight. What is its simplest formula?69.

AsOAAs2 B As C

D /E /

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SAT Subject Test: Chemistry: Diagnostic Test www.learningpod.com 2014 Learninpod, Inc.

Answers & Explanations

SAT Subject Test: Chemistry: Diagnostic Test

Atomic mass is the averaged mass of the atoms of an element, taking into account the relative abundance of the various

isotopes in a naturally occurring substance.

Electronegativity is a measure of the ability of an atom to attract the electrons in a bond. A common scale is the Pauling scale.

The atomic radius is defined as the average distance betw een a nucleus and the outermost electrons. It is usually measured as

half of the distance betw een tw o nuclei of an element in its elemental form.

The atomic number is defined as the number of protons in a given element. It defines an element.

The ionization potential, or ionization energy, is the energy required to remove an electron from the valence shell of a gaseous

atom.

Krypton is the f irst element w ith a f illed 4 p orbital, so the element must fall after it in the periodic table. Rb is the only element

w ith enough electrons to have a f illed 4 p subshell.

Of the tw o ions and , has the same electron configuration as argon, a noble gas, and therefore has all paired

electrons.

POD

Answ er (A) is correct.

Atomic mass

1.

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Answ er (D) is correct.

Electronegativity

2.

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Answ er (C) is correct.

Atomic radius

3.

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Answ er (B) is correct.

Atomic number

4.

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Answ er (E) is correct.

Ionization potential

5.

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Rb

6.

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Answ er (C) is correct.7.

$M

$M

$B

$M

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Fe has 26 electrons, configured as listed.

An element is a substance that cannot be further broken dow n by chemical means.

A cation is an ionic species w ith a positive charge. An anion is an ionic species w ith a negative charge.

Inert gases, elements in Group 0 (or VIII) of the periodic table, contain a full octet of valence electrons in their outermost shells;

this makes these elements the least reactive.

All atoms of a given element have the same numbers of protons.

A calorimeter is an apparatus used to measure the heat released or absorbed by a reaction.

A barometer is used to measure atmospheric pressure.

A balance is used to measure w eight.


Fe

8.

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Element

9.

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Cation

10.

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Inert Gas

11.

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Element

12.

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Calorimeter

13.

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Barometer

14.

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Balance

15.

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Centrifuges can spin at very high rotor speeds (e.g., 60,000 rpm) to sediment out particles in suspension.

The Gibbs free energy is the energy of a system available to do w ork. The change in Gibbs free energy, , can be

determined for a given reaction w ith the equation = T . Reactions w ith a negative change in Gibbs free

energy are spontaneous.

Specif ic heat is the amount of heat required to raise the temperature of one unit mass of a substance one degree Celsius.

The heat of formation is the heat absorbed or released during the formation of a pure substance from its elements at constant

pressure.

NaOH completely dissociates in w ater to form and ions, the latter of w hich is a very strong base. This results in

a solution w ith a very high pH ( 7).

COOH does not completely dissociate in w ater. There w ould be some undissociated COOH and some

+ ; therefore, it w ould be a w eak acid w ith a pH slightly less than 7.

HBr completely dissociates into and in w ater; this solution w ould have a very low pH ( 7).

CsCl is a salt; it completely dissociates in w ater into and . This w ill form an ionic solution w ith a neutral pH.


Centrifuge

16.

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Gibbs free energy

17.

9

9 9 9

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Specific heat

18.

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Heat of formation

19.

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NaOH

20.

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COOH

21.

$)

$)

$)

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HBr

22.

#S

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CsCl

23.

$T

$M

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To answ er this question, you need to w rite the Lew is dot diagrams and then use any one of several formulas to f ind the formal

charge. One such formula is formal charge = valence electrons [number of bonds + number of nonbonding electrons]. The

Lew is dot structure of show s that nitrogen is double bonded to one oxygen, single bonded to another oxygen, and

single bonded to another oxygen that is single bonded to a hydrogen-there are no lone electron pairs on the nitrogen. Using the

formula, formal charge is equal to the valence electrons of nitrogen (5) minus the sum of the number of bonds and the number

of nonbonding electrons, w hich in this case is 4. So, the formal charge on the nitrogen is 5 minus 4, or 1.

In a solution, HCl contributes 1 mol of ions per mol of HCl. NaOH also contributes 1 mol of ions per mol of NaOH.

Therefore, to neutralize the 80 mL of a 0.5M NaOH solution, you must have the same number of moles of HCl. The number of

moles of NaOH you have is:

(0.80 L)(0.5 mol/L) = 0.04 mol of NaOH

and therefore 0.04 mol of ions.

To calculate the volume of a 1M solution of HCl, you w ill need to get 0.04 mol, perform the follow ing calculation:

(1 mol/L)(X L) = 0.04 mol

X L = 0.04 L

X mL = 40 mL

An electrolyte is a substance that ionizes to yield an electrically conducting solution. A strong electrolyte is one that ionizes

completely or nearly completely, and a w eak electrolyte doesn't ionize very much at all. Examples of strong electrolytes are

NaCl, KCl, HCl, HBr, and HI. Examples of w eak electrolytes are w ater, HF, acetic acid, benzoic acid, and ammonia.

If an element loses an electron, it w ill have more protons than electrons and w ith this stronger positive charge can pull the

electrons in closer. Therefore, its ionic radius w ould be less than its atomic radius. Thus, Na, K, Mg, and Ca w ill all lose

electrons and become smaller. Cl, on the other hand, w ill gain an electron; its positive nucleus cannot hold on to that extra

electron as tightly, and its ionic radius is larger than its atomic radius.

A crystal is a solid w hose atom, ions, or molecules are arranged in a regular 3D lattice structure. The basic repeating structure

is know n as the unit cell.


+1

24.

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40 mL

25.

0)

0)

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Potassium chloride

26.

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Cl

27.

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unit cell

28.

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The oxidation state of nitrogen in is 0. In it is +1, in it is 3, in it is +4, and in it is +6. Oxygen is

typically 2 and H is usually +1. Therefore, is the correct answ er.

In order to answ er this question correctly, you need to know the f irst law of thermodynamics: The change in internal energy,

, equals the amount of heat transferred, q, minus the amount of w ork transferred, w . If heat is added to the system, q is

positive; if it is transferred to the surrounding, it is negative. If w ork is done by the system, w is positive; if w ork is done on the

system, w is negative. In this example, 500 joules of heat is added to the system, so q is equal to 500 joules. The system does

75 joules of w ork on the surrounding, so w is equal to 75 joules. Plugging these into our equation, the change in internal is

equal to 500 minus 75, or 425 joules.

NaOH and (a strong base and a strong acid) both dissociate completely in into their ionic components ,

, 2 , and , w hich then form a salt and w ater. The driving force of this double displacement reaction is the

formation of w ater by the and ions.

To answ er this question, you simply need to know the definition of ground state and excited state. The ground state of an atom

is the state in w hich all the electrons in the atom are in their low est energy state. If any electron has absorbed energy and

been promoted to a higher energy orbital in the atom w ithout actually leaving the atom, the atom is said to be in an excited state.

An atom can have any number of excited states depending on how many electrons have been promoted and w hat orbitals

they end up in. Usually, excited states are unstable and the atom w ill release energy and return to the ground state. So w hich

of these choices explains the difference betw een these tw o definitions? Choice D: When electrons gain energy and change

w hich atomic orbital they're in, they change their quantum numbers, w hich in turn changes the electronic configuration around

the nucleus.

This question deals w ith solubility constant and the common ion effect. The f irst step to solving this problem is to express the

solubility product constant, w hich is the ion product of the saturated solution, as the product of the concentration of ion

and the concentration of the hydroxide ion squared. Second, you must determine the minimum concentration of hydroxide

necessary to precipitate the Mg . From the equation given, you can solve for the concentration of hydroxide, w hich is

the square root of the divided by the concentration of . Substituting in the values provided in the question, you

should f ind that the concentration is equal to mol/L. That means that the pOH of the solution w ill be 3; therefore, the pH

must be 11.


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425 J

30.

9

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it is a neutralization reaction

31.

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The electronic configuration

32.

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11

33.

#

/,

#

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The random motion of a gas holds the most translational kinetic energy.

This question asks you w hich of the choices w ill increase the rate at w hich ice melts in a closed container. If you low er the

temperature, you are tipping the equilibrium tow ard the ice, so B is w rong. To deal w ith pressure changes, w e must apply Le

Chtelier's principle, w hich says that a system in equilibrium that is subject to stress w ill shift its equilibrium so as to relieve the

stress. If the pressure is low ered, as in choice C, the system w ill counteract the change in pressure by shifting its equilibrium

tow ard the phase that is less dense. In the case of w ater, that is the ice. Remember that w ater has a strange property in that

the solid form, ice, at zero degrees Celsius is less dense than the liquid phase, w ater, at that temperature. Since the reduction

of pressure drives the systems to produce ice, choice C is incorrect. How ever, choice D, an increase in pressure, w ill have

the opposite effect and the w ater w ill be produced preferentially, meaning that the ice is melting faster. Choices A and E both

favor ice formation.

The most polar bond is the one that has the greatest difference in the electronegativities of the tw o elements. Of the choices,

HF is the most polar since hydrogen and f luorine are the farthest apart in the periodic table.

This question asks you to determine the rate law of the reaction for the formation of ammonia, . A rate law is an

equation that gives the relationship betw een the rate of the reaction and the concentration of the reactants, each raised to an

appropriate pow er that depends on the exact reaction. For example, the rate of this reaction is equal to k x y ,

w here k is the rate constant and x and y are real numbers. k, x , and y can only be determined experimentally by systematically

varying the initial concentration of one reactant. Since there is no experimental data, there w ay for us to know w hat these

values are.

10 N is equal to 5 M as each molecule has 2 ions associated w ith it. Use the equation =

. (100)(5) = (800). = 5/8.

This question asks you w hich molecule contains both ionic and covalent bonds. Choice C is ammonium sulfate. The bonds

betw een nitrogen and hydrogen in the ammonium ion and betw een sulfur and oxygen in the sulfate ion are all covalent.

How ever, the bond betw een the ammonium ion and the sulfate ion is an ionic bond.


Gas

34.

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Raising the pressure

35.

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HF

36.

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cannot be determined from the information given

37.

< >

< >

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5/8 M

38.

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Charles's law states that / = / , and you must convert Celsius to Kelvin. Rearrange your equation to / =

/ . = 303 and = 293, and the ratio is 303/293.

This question tests your know ledge of Le Chtelier's principle. What w ill happen to this reaction if more chlorine is added?

Adding more chlorine puts a stress on the system, and the system alleviates that stress by using up that added chlorine: The

equilibrium shifts to the left.

This is a redox reaction. We can tell this because the oxidation states of the species change during the reaction. The oxidation

state of bromine in the product, molecular bromine, is 0. The oxidation state of bromine in the bromide reactant is 1, and the

oxidation state of the bromine in the bromate is +5. The fact that the bromine of one reactant reduces the bromine of the other

should not bother you, since it is immaterial. The important thing in redox reactions is the number of electrons. Since bromide is

acting as a reducing agent, going from the 1 oxidation state to the 0 oxidation state, it transfers one electron per bromide.

Bromate, how ever, is going from the +5 oxidation state to the 0 oxidation state, requiring 5 electrons. Bromate gets these

electrons from bromide, requiring 5 of them. The ratio of bromate to bromide is therefore 1 to 5.

To f igure out how many moles of are in 120 mL of a 1.5 M solution, perform the follow ing calculation:

(1.5 mol/L)(0.12 L) = 0.18 mol

To f igure out how many grams are in 0.18 mol, you need to multiply the number of moles by the formula w eight:

(106 g/mol)(0.18 mol) = 19 grams

Thomas Graham stated in 1832 that the rates for tw o gases diffusing is inversely proportional to the square root of the molar

mass. Therefore, : = . Simplify this equation and you have a ratio of diffusion rates of 4:1 for : .


303:293

40.

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It w ill be shifted to the left.

41.

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1:5

42.

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19 g

43.

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4:1

44.

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Questions of nuclear chemistry can, as in this case, often be translated into basic arithmetic problems. Based on the law of

conservation of mass, the sum of the mass numbers (superscripted) must be the same on each side of the arrow . Similarly,

conservation of charge mandates that the sum of the nuclear charges (subscripted) be the same on each side of the arrow .

We can thus translate the nuclear question posed into tw o elementary arithmetic questions:

27 + 4 = 30 + ? and 13 + 2 = 15 + ?

Solving these tw o problems results in a mass number of 1 and a nuclear charge of 0; this set of values corresponds to the

neutron . As for the w rong choices, in choice A, the beta particle is a nuclear electron and thus has mass and charge

numbers of 0 and 1, respectively. The positron, choice B, has the mass of an electron but the opposite charge; the numbers

are thus 0 and +1, respectively. Alpha particles are helium nuclei; choice C corresponds to a mass number of 4 and a nuclear

charge of +2. Choice E, gamma ray, is short-w avelength electromagnetic radiation, i.e., light; as such, it has no mass and no

charge.

Cr metal in its elemental state has an oxidation number of 0. In , O has an oxidation number of 2 and K has an

oxidation number of +1.

O(-2)(7) = -14

K(+1)(2) = 2

Total -12

Cr must cancel out the 12, so the tw o Cr molecules must have a charge of +12. 12/2 = +6 for each Cr molecule.

When a Ca molecule loses an electron to become , it goes from 20 to 19 electrons. K in its elemental state has 19

electrons.

This question requires you to know something about the periodicity of the elements. Basically, all you are asked is w hy all the

halogens behave so similarly in reactions. You know from studying the periodic table that there must be something that repeats

or the table w ould not be periodic. What is it about the elements in a column that are the same? The number of valence

electrons. Since the identity of the valence electrons is the same in each column, or group, and columns in the s block have

valence s electrons, columns in the p block have valence s and p electrons, and columns in the d block have valence s and d

electrons, the only thing that can make them act similarly is the number of electrons in these shells. Furthermore, the number of

electrons in the valence shell affects the reactivity and stability of the shell. The number of electrons affects the ionization

energy and electron aff inity, w hether the atom w ill form cations or anions, and even the number of bonds the atom can

participate in.


Neutron

45.

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0 to 6

46.

.

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and K

47.

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they have similar outer shell electron configurations

48.

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The atomic w eight of an element depends on the number of protons and neutrons in its nucleus; those numbers are alw ays

unique to a particular element, regardless of the number of electrons in the species. The ionization potential depends chiefly on

the radius of the parent atoms and the effective charge of the nucleus. Since and have different numbers of protons

by definition, they w ill have different effective charges, different atomic radii, and therefore different ionization potential. Choice

B, how ever, says that the tw o ions have the same electronic configuration. Chlorine belongs to the third period and potassium

belongs to the fourth, so in their unionized forms, chlorine's third shell contains seven electrons and potassium's fourth shell

contains one electron. If chlorine gains one electron and potassium loses one electron, both w ill have eight electrons in the third

shell, w hich becomes the valence shell. So, the potassium and chlorine ions described in the question both contain the samenumber of electrons and the same number of occupied orbitals and thus share the same electronic configuration.

has the largest ionic radius. When an atom gains an electron, positive protons in the nucleus cannot hold on to the

electrons as w ell and therefore the electron shells are able to spread farther out.

The balanced equation looks like this:

8 + + 5 + 5 + 4 .

One and f ive yield a total charge of +17.

The balanced equation looks like this:

1Ag 1 + 2

1 + 1 + 2 = 4

1Ag /2 = X/11

X = 11/2

5.5 moles


electronic configuration

49.

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Answ er (E) is correct.50.

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+17

51.

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4

52.

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5.5

53.

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Ag = 108

N = (14)2 = 28

H = (1)6 = 6

Total molecular w eight: 108 + 28 + 6 = 142

Percent Ag: (108/142) 100% = 76.1%

Balanced equation: + 5 3 + 4

160 g /32 g/mol = 5 moles

88 g /44 g/mol = 2 moles

Therefore, oxygen is the limiting reagent; 5 moles of and one mole of w ill form 3 moles of .

3 moles x 44 g/mol = 132 g

= is the equation you w ill use.

Oxygen:(200)(200) = (500)

= 80 mmHg, the new pressure

Neon: (300)(100) = (500)

= 60 mm Hg

60 is the mass number (the number of protons + the number of neutrons). 27 is the atomic number (the number of protons). In a

beta-decay reaction, the atomic number increases by one as a neutron turns into a proton and an electron that is ejected.

Ionic solutions w ill conduct electricity. The NaCl w ill dissociate to become and . The same occurs w hen you melt the

NaCl. Solid NaCl and pure w ater are not ionic solutions.


76.1

54.

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132

55.

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60 mm Hg

56.

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28

57.

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III and IV

58.

/B

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NaCl is an ionic compound w ith ionic bonds because it is formed w hen Na donates an electron to Cl. The bond is formed by the

electrostatic interaction betw een the positive and negative ions.

Glucose molecules carry no electrical charge, so there are no electrical charges in the solution to provide conduction.

This Roman-numeral question asks w hich of the given statements describe a galvanic cell (remember more than one of the

answ ers may be correct). Galvanic cells are capable of spontaneous reactions. In all electrochemical cells, oxidation occurs at

the anode and reduction occurs at the cathode. In addition, the anode in a galvanic cell is negative, meaning that it is a source

of electrons. Since a species loses electrons w hen it is oxidized, this should make sense. There is a trick to remembering these

facts. In a galvanic cell, oxidation occurs at the anode, w hich is negative. Alphabetically, anode comes before cathode,

oxidation before reduction, and negative before positive. How ever, this little trick only w orks for galvanic cells.

34 g of at 17 g/mol equals 2 mol combusted. Tw o moles are combusted at 81 kcal/mol. This equation w ould be (2 mol)(81

kcal/mol) = 162 kcal.

The s subshells contain only 2 electrons. Their principal, azimuthal, and magnetic quantum numbers are identical, but due to

Pauli's exclusion principle their spin quantum numbers must be +1/2 and 1/2. Therefore, they have opposite spins.

A buffer is a solution made from a mixture of a w eak acid and a salt containing its anion. Buffers resist pH change due to the

addition of acid or base. Thus, to make a buffer solution w ith a w eak monoprotic acid, the addition of the corresponding salt is

required. This salt must contain the anion, or conjugate base, of the acid.

If the temperature of an exothermic reaction is increased, the reaction shifts to the left. If the temperature of an endothermic

reaction is increased, it shifts to the right. The reaction in question has a negative enthalpy of reaction, meaning that it is an

exothermic reaction. If the temperature of this reaction is increased, the reaction w ill shift to the left.


Ionic

59.

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Light bulb would remain dark.

60.

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I and III

61.

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162 kcal

62.

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they must have opposite spins

63.

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its conjugate base

64.

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It w ill be shifted to the left.

65.

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Boyle's law states that at constant temperatures the volume of a gas is inversely proportional to its pressure. Statement II is

therefore correct. Statement III is also correct as density, defined as mass divided by volume, w ill increase proportionally to

pressure since the volume is decreasing.

Molality equals the number of moles of solute/kg of solvent. 200 g/[24 g/mol Mg + 71 g/mol for 2 Cl] is the number of moles of

solute. This is also the value of molality since it is added to 1 kg of solvent.

100 g = 100 g/2 g/mol = 50 mol

100 g = 100 g/32 g/mol = 100/32 mol

2 + 2

Therefore, oxygen is the limiting reagent since it is the compound in the least amount. According to the balanced equation, for

every mole of oxygen you w ill get tw o moles of w ater. Therefore, to discover how many moles of w ater w ould be produced,

multiply the number of moles of oxygen you begin w ith by tw o, to account for the fact that tw o moles of w ater are produced

for every mole of oxygen. Thus, the correct equation w ould be (2 mol /1 mol of )(100/32 mol of ).

Perhaps the easiest w ay to solve such a problem is to imagine a particular sample mass of the compound. For the sake of

convenience, choose 100 grams, though any mass w ill let you arrive at the correct answ er. Because the oxide of arsenic

contains only arsenic and oxygen, a 100-gram sample w ould contain 65.2 grams of arsenic and the remainder, 34.8 grams,

must be oxygen. To f ind the ratio betw een these tw o elements in the compound, divide the mass of arsenic by the atomic

w eight of arsenic, 74.7 grams/ mol, and the mass of oxygen by the atomic w eight of oxygen, 16 grams/mol. This w ill give the

mole ratio betw een arsenic and oxygen in the compound. To convert to a more easily useful ratio, divide both by the low est

number of the tw o, in this case arsenic. This gives us a ratio of 1 mole of arsenic to 2.5 moles oxygen, w hich is better stated

by doubling both numbers and getting 2 moles of arsenic to 5 moles of oxygen. This w ould correspond to the formula in choice

D, .


II and III

66.

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200/(24 + 71)

67.

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2(100/32)

68.

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Answ er (D) is correct.69.

/

/

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