Chemistry answers




Chemistry answers


The following texts are the property of their respective authors and we thank them for giving us the opportunity to share for free to students, teachers and users of the Web their texts will used only for illustrative educational and scientific purposes only.


The information of medicine and health contained in the site are of a general nature and purpose which is purely informative and for this reason may not replace in any case, the council of a doctor or a qualified entity legally to the profession.



Chemistry answers




AP Chemistry

Study Guide

1.         According to the law of multiple proportions:

A)   if the same two elements form two different compounds, they do so in the same ratio.

B)   it is not possible for the same two elements to form more than one compound.

C)   the ratio of the masses of the elements in a compound is always the same.

D)   the total mass after a chemical change is the same as before the change.

E)   none of these


2.         Which of the following pairs of compounds can be used to illustrate the law of multiple proportions?

A)   NH4 and NH4Cl

B)   ZnO2 and ZnCl2

C)   H2O and HCl

D)   NO and NO2

E)   CH4 and CO2


3.         Many classic experiments have given us indirect evidence of the nature of the atom. Which of the experiments listed below did not give the results described?

A)   The Rutherford experiment proved the Thomson "plum-pudding" model of the atom to be essentially correct.

B)   The Rutherford experiment was useful in determining the nuclear charge on the atom.

C)   Millikan's oil-drop experiment showed that the charge on any particle was a simple multiple of the charge on the electron.

D)   The electric discharge tube proved that electrons have a negative charge.


4.         Which of the following statements from Dalton's atomic theory is no longer true, according to modern atomic theory?

A)   Elements are made up of tiny particles called atoms.

B)   Atoms are not created or destroyed in chemical reactions.

C)   All atoms of a given element are identical.

D)   Atoms are indivisible in chemical reactions.

E)   All of these statements are true according to modern atomic theory.


5.         The first people to attempt to explain why chemical changes occur were

A)   alchemists.

B)   metallurgists.

C)   physicians.

D)   physicists.

E)   the Greeks.


6.         The Greeks proposed that matter consisted of four fundamental substances:

A)   fire, earth, water, air

B)   fire, metal, water, air

C)   earth, metal, water, air

D)   atoms, fire, water, air

E)   atoms, metal, fire, air


7.         The first chemist to perform truly quantitative experiments was

A)   Paracelsus.

B)   Boyle.

C)   Priestly.

D)   Bauer.

E)   Lavoisier.


8.         The scientist who discovered the law of conservation of mass and is also called the father of modern chemistry is

A)   Proust.

B)   Boyle.

C)   Priestly.

D)   Bauer.

E)   Lavoisier.


9.         Which of the following pairs can be used to illustrate the law of multiple proportions?

A)   SO and SO2

B)   CO and CaCo3

C)   H2O and C12H22O11

D)   H2SO4 and H2S

E)   KCl and KClO2


10.       The chemist credited for inventing a set of symbols for writing elements and a system for writing the formulas of compounds (and for discovering selenium, silicon, and thorium) is

A)   Boyle.

B)   Lavoisier.

C)   Priestly.

D)   Berzelius.

E)   Dalton.


11.       What element (in trace amounts) has been shown to help in protecting against heart disease and cancer?

A)   silicon

B)   oxygen

C)   selenium

D)   copper

E)   potassium


12.       The first scientist to show that atoms emit any negative particles was

A)   J. J. Thomson.

B)   Lord Kelvin.

C)   Ernest Rutherford.

D)   William Thomson.

E)   John Dalton.


13.       The scientist whose alpha-particle scattering experiment led him to conclude that the nucleus of an atom contains a dense center of positive charge is

A)   J. J. Thomson.

B)   Lord Kelvin.

C)   Ernest Rutherford.

D)   William Thomson.

E)   John Dalton.


14.       Which one of the following statements about atomic structure is false?

A)   The electrons occupy a very large volume compared to the nucleus.

B)   Almost all of the mass of the atom is concentrated in the nucleus.

C)   The protons and neutrons in the nucleus are very tightly packed.

D)   The number of protons and neutrons is always the same in the neutral atom.

E)   All of the above statements (a-d) are true.


15.       If the Thomson model of the atom had been correct, Rutherford would have observed

A)   alpha particles going through the foil with little or no deflection.

B)   alpha particles greatly deflected by the metal foil.

C)   alpha particles bouncing off the foil.

D)   positive particles formed in the foil.

E)   None of the above observations is consistent with the Thomson model of the atom.


16.       Rutherford's experiment was important because it showed that:

A)   radioactive elements give off alpha particles.

B)   gold foil can be made to be only a few atoms thick.

C)   a zinc sulfide screen scintillates when struck by a charged particle.

D)   the mass of the atom is uniformly distributed throughout the atom.

E)   an atom is mostly empty space.


17.       Which of the following name(s) is(are) correct?

1.   sulfide S2–

2.   ammonium chloride NH4Cl

3.   acetic acid HC2H3O2

4.   barium oxide BaO

A)   all

B)   none

C)   1, 2

D)   3, 4

E)   1, 3, 4


18.       Which of the following atomic symbols is incorrect?







19.       The element rhenium (Re) exists as two stable isotopes and 18 unstable isotopes. Rhenium-185 has in its nucleus

A)   75 protons, 75 neutrons.

B)   75 protons, 130 neutrons.

C)   130 protons, 75 neutrons.

D)   75 protons, 110 neutrons.

E)   not enough information is given.


20.       Which statement is not correct?

A)   The mass of an alpha particle is 7300 times that of the electron.

B)   An alpha particle has a 2+ charge.

C)   Three types of radioactive emission are gamma rays, beta rays, and alpha particles.

D)   A gamma ray is high-energy light.

E)   There are only three types of radioactivity known to scientists today.


21.       has

A)   20 protons, 20 neutrons, and 18 electrons.

B)   22 protons, 20 neutrons, and 20 electrons.

C)   20 protons, 22 neutrons, and 18 electrons.

D)   22 protons, 18 neutrons, and 18 electrons.

E)   20 protons, 20 neutrons, and 22 electrons.


24.       All of the following are true except:

A)   Ions are formed by adding electrons to a neutral atom.

B)   Ions are formed by changing the number of protons in an atom's nucleus.

C)   Ions are formed by removing electrons from a neutral atom.

D)   An ion has a positive or negative charge.

E)   Metals tend to form positive ions.


25.       Which of the following statements is (are) true?

A)    have the same number of neutrons.

B)    are isotopes of each other because their mass numbers are the same.

C)   .

D)   a and b

E)   a and c


26.       Which among the following represent a set of isotopes? Atomic nuclei containing:

 I.        20 protons and 20 neutrons.

II.        21 protons and 19 neutrons.

III.      22 neutrons and 18 protons.

IV.      20 protons and 22 neutrons.

V.     21 protons and 20 neutrons.

A)   I, II, III

B)   III, IV

C)   I, V

D)   I, IV and II, V

E)   No isotopes are indicated.



27.       By knowing the number of protons a neutral atom has, you should be able to determine

A)   the number of neutrons in the neutral atom.

B)   the number of electrons in the neutral atom.

C)   the name of the atom.

D)   two of the above.

E)   none of the above


28.       The number of neutrons in an atom is the same for all neutral atoms of that element.

A)   True

B)   False


29.       The average mass of a carbon atom is 12.011. Assuming you were able to pick up only one carbon unit, the chances that you would randomly get one with a mass of 12.011 is

A)   0%.

B)   0.011%.

C)   about 12%.

D)   12.011%.

E)   greater than 50%.


30.       The number of electrons in an atom is the same for all neutral atoms of that element.

A)   True

B)   False


31.       An ion is formed

A)   by either adding or subtracting protons from the atom.

B)   by either adding or subtracting electrons from the atom

C)   by either adding or subtracting neutrons from the atom.

D)   All of the above are true.

E)   Two of the above are true


32.       Which of the following statements are true of uranium-238?

 I.   Its chemical properties will be exactly like those of uranium-235.

II.  Its mass will be slightly different from that of an atom of uranium-235.

III. It will contain a different number of protons that an atom of uranium-235.

IV. It is more plentiful in nature than uranium-235.

A)   III, IV

B)   I, II, III

C)   I, II, IV

D)   II, III, IV

E)   all of these


33.       An isotope, X, of a particular element has an atomic number of 7 and a mass number of 15. Therefore,

A)   X is an isotope of nitrogen

B)   X has 8 neutrons per atom

C)   X has an atomic mass of 14.0067

D)   a and b

E)   a, b, and c


34.       Write the symbol for each of the following elements.

a)       silver                      _____________

b)       calcium                  _____________

c)       iodine                    _____________

d)       copper                    _____________

e)       phosphorus            _____________


35.       How many oxygen atoms are there in one formula unit of Ca3(PO4)2?

A)   2

B)   4

C)   6

D)   8

E)   none of these


36.       The formula of water, H2O, suggests

A)   there is twice as much mass of hydrogen as oxygen in each molecule.

B)   there are two hydrogen atoms and one oxygen atom per water molecule.

C)   there is twice as much mass of oxygen as hydrogen in each molecule.

D)   there are two oxygen atoms and one hydrogen atom per water molecule.

E)   none of these


37.       Which of the following are incorrectly paired?

A)   K, alkali metal

B)   Ba, alkaline earth metal

C)   O, halogen

D)   Ne, noble gas

E)   Ni, transition metal


38.       Which of the following are incorrectly paired?

A)   Phosphorus, Pr

B)   Palladium, Pd

C)   Platinum, Pt

D)   Lead, Pb

E)   Potassium, K


39.       Which of the following are incorrectly paired?

A)   Copper, Cu

B)   Carbon, C

C)   Cobalt, Co

D)   Calcium, Ca

E)   Cesium, Ce


40.       All of the following are characteristics of metals except:

A)   good conductors of heat

B)   malleable

C)   ductile

D)   often lustrous

E)   tend to gain electrons in chemical reactions


41.       All of the following are characteristics of nonmetals except:

A)   poor conductors of electricity

B)   often bond to each other by forming covalent bonds

C)   tend to form negative ions in chemical reactions with metals

D)   appear in the upper left-hand corner of the periodic table

E)   do not have a shiny (lustrous) appearance


42.       What are the forms of elemental carbon?

A)   graphite and diamond

B)   graphite, diamond, and buckminsterfullerene

C)   graphite and buckminsterfullerene

D)   diamond and buckminsterfullerene

E)   diamond, graphite, and carbonite


43.       Which metals form cations with varying positive charges?

A)   transition metals

B)   Group 1 metals

C)   Group 2 metals

D)   Group 3 metals

E)   metalloids


44.       A species with 12 protons and 10 electrons is

A)   Ne2+

B)   Ti2+

C)   Mg2+

D)   Mg

E)   Ne2–


45.       The correct name for LiCl is

A)   lithium monochloride

B)   lithium (I) chloride

C)   monolithium chloride

D)   lithium chloride

E)   monolithium monochloride


46.       The correct name for FeO is

A)   iron oxide

B)   iron (II) oxide

C)   iron (III) oxide

D)   iron monoxide

E)   iron (I) oxide



47.       The correct name for Ca2+ is

A)   calcium

B)   calcium (II) ion

C)   calcium ion

D)   calcium (I) ion

E)   monocalcium ion


48.       The formula for calcium bisulfate is

A)   Ca(SO4)2

B)   CaS2

C)   Ca(HSO4)2

D)   Ca2HSO4

E)   Ca2S


49.       Which of the following is incorrectly named?

A)   Pb(NO3)2, lead(II) nitrate

B)   NH4ClO4, ammonium perchlorate

C)   PO43–, phosphate ion

D)   Mg(OH)2, magnesium hydroxide

E)   NO3–, nitrite ion


50.       All of the following are in aqueous solution. Which is incorrectly named?

A)   H2SO4, sulfuric acid

B)   H3PO4, phosphoric acid

C)   H3PO4, phosphoric acid

D)   HCN, cyanic acid

E)   HCl, hydrochloric acid


51.       All of the following are in aqueous solution. Which is incorrectly named?

A)   HC2H3O2, acetic acid

B)   HBr, bromic acid

C)   H2SO3, sulfurous acid

D)   HNO2, nitrous acid

E)   HClO3, chloric acid


52.       Which of the following pairs is incorrect?

A)   NH4Br, ammonium bromide

B)   K2CO3, potassium carbonate

C)   BaPO4, barium phosphate

D)   CuCl, copper(I) chloride

E)   MnO2, manganese (IV) oxide


53.       Write the names of the following compounds:

 a)      FeSO4                                  ________________

b)       NaC2H3O2                         ________________

c)       KNO2                                   ________________

d)       Ca(OH)2                             ________________

e)       NiCO3                                  ________________


54.       Write the chemical formulas for the following compounds or ions.

 a)      nitrate ion                                _________

b)       aluminum oxide                       _________

c)       ammonium ion                         _________

d)       perchloric acid                         _________

e)       copper(II) bromide                  _________


55.       How many atoms (total) are there in one formula unit of Ca3(PO4)2?


56.       Three samples of a solid substance composed of elements A and Z were prepared. The first contained 4.31 g A and 7.69 g Z. The second sample was 35.9% A and 64.1% Z. It was observed that 0.718 g A reacted with Z to form 2.00 g of the third sample. Show that these data illustrate the law of definite composition.


57. Explain how Dalton’s atomic theory accounts for:

a) the law of conservation of mass.

b) the law of definite composition.

c)         the law of multiple proportion.


58.       Complete the following table.



# protons

# neutrons

# electrons

Net Charge























59.       Complete the following table.


Symbol                                               69Ga+3              

Number of protons                              34

Number of neutrons                            46

Number of electrons                          

Atomic number                                  

Mass number                                      

Net charge                                           0


60.       Arsenopyrite is a mineral containing As, Fe, and S. Classify each element as metal, nonmetal, or metalloid.


Use the following to answer questions 61-70:


Name the following compounds:

61.       Al2(SO4)3

62.       NH4NO3

63.       NaH

64.       K2Cr2O7

65.       CCl4

66.       AgCl

67.       CaSO4

68.       HNO3

69.       N2O3

70.       SnI2


Use the following to answer questions 71-80:


Write the formula for:


71.       sodium dichromate

72.       iron (III) oxide

73.       dinitrogen trioxide

74.       cobalt (II) chloride

75.       aluminum hydroxide

76.       hydrosulfuric acid

77.       sulfurous acid

78.       nitric acid

79.       phosphoric acid

80.       acetic acid


81.       A sample of chemical X is found to contain 5.0 grams of oxygen, 10.0 grams of carbon, and 20.0 grams of nitrogen. The law of definite proportion would predict that a 69 gram sample of chemical X should contain how many grams of carbon?

A)   5.0 grams

B)   6.9 grams

C)   10. grams

D)   15 grams

E)   20 grams


82.       Consider the following two compounds:  H2O According to the law of multiple proportions, the ratio of hydrogen atoms per gram of oxygen in H2O to hydrogen atoms per gram of oxygen in H2O2 is:

A)   1:1

B)   2:1

C)   1:2

D)   2:2

E)   4:1


83.       You are given a compound with the formula MCl2, in which M is a metal.  You are told that the metal ion has 26 electrons.  What is the identity of the metal?

A)   Co

B)   Al

C)   Fe

D)   Cr

E)   Ni


84.       Which of the following names is incorrect?

A)   cobalt(II) chloride

B)   magnesium oxide

C)   aluminum(III) oxide

D)   diphosphorus pentoxide

E)   All of the above names are correct.


85.       Which of the following statements is true?

A)   Ions are formed by adding or removing protons or electrons.

B)   Scientists believe that solids are mostly open space.

C)   Heating water with a Bunsen burner results in a 2:1 mixture of hydrogen and oxygen gases.

D)   At least two of the above statements (a-c) are true.

E)   All of the statements (a-c) are false.


86.       How many protons and electrons does the most stable ion for oxygen have?

 # protons   # electrons


A)               10 8


B)               8              6


C)               6              8


D)               8              8


E)               8              10


87.       How many of the following postulates of Dalton's atomic theory are still scientifically accepted?

 I.        All atoms of the same element are identical.

II.        Compounds are combinations of different atoms.

III.      A chemical reaction changes the way atoms are grouped together.

IV.      Atoms are indestructible.


A)   0

B)   1

C)   2

D)   3

E)   4



Answer Key


1.         E

2.         D

3.         A

4.         C

5.         E

6.         A

7.         B

8.         E

9.         A

10.       D

11.       C

12.       A

13.       C

14.       D

15.       A

16.       E

17.       A

18.       E

19.       D

20.       E

21.       A

22.       B

23.       E

24.       B

25.       E

26.       D

27.       D

28.       B

29.       A

30.       A

31.       B

32.       C

33.       D

34.       a) Ag, b) Ca, c) I, d) Ci, e) P

35.       D

36.       B

37.       C

38.       A

39.       E

40.       E

41.       D

42.       B

43.       A

44.       C

45.       D

46.       B

47.       C

48.       C

49.       E

50.       D

51.       B

52.       C

53.       a) iron (II) sulfate

b) sodium acetate

c) potassium nitrite

d) calcium hydroxide

e) mickel (II) carbonate

54.       a) NO3        b) Al2O3        c) NH4+         d) HClO4       e) CuBr2

55.       13         

56.       See Sec. 2.2 of Zumdahl, Chemistry.    

57.       See Sec. 2.3 of Zumdahl, Chemistry.


Symbol            # protons         # neutrons       # electrons      Net Charge

Pb                82                124              82                0

Ga                31                38                28                3+

Te                52                75                54                2

Mn               25                29                23                2+


59.                                   Symbol        69Ga+3           80Se

Number of protons          31                34

Number of neutrons        38                46

Number of electrons        28                34

Atomic number                31                34

Mass number                   69                80

Net charge                       +3                0


60.       As = metalloid, Fe = metal, S = nonmetal    

61.       aluminum sulfate    

62.       ammonium nitrate    

63.       sodium hydride    

64.       potassium dichromate    

65.       carbon tetrachloride    

66.       silver chloride    

67.       calcium sulfate    

68.       nitric acid    

69.       dinitrogen trioxide    

70.       tin(II) iodide    

71.       Na2Cr2O7    

72.       Fe2O3     

73.       N2O3    

74.       CoCl2    

75.       Al(OH)3    

76.       H2S         

77.       H2SO3    

78.       HNO3    

79.       H3PO4    

80.       CH3COOH    

81.       E

82.       B

83.       E

84.       C

85.       B

86.       E

87.       C



Source :

Web site link:

Author : not indicated on the source document of the above text

Google key word : Chemistry answers file type : doc


If you are the author of the text above and you not agree to share your knowledge for teaching, research, scholarship (for fair use as indicated in the United States copyrigh low) please send us an e-mail and we will remove your text quickly.


Chemistry answers


If you want to quickly find the pages about a particular topic as Chemistry answers use the following search engine:




Chemistry answers


Please visit our home page Terms of service and privacy page




Chemistry answers