PrELIM EXAM CHEMISTRY

8/3/2019 PrELIM EXAM CHEMISTRY

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public of the PhilippinesDAVAO ORIENTAL STATE COLLEGE OF SCIENCE AND TECHNOLOGY

San Isidro Campus, Davao Orientalset b.

Chem 11Final Examination

struction. Encircle the letter that corresponds with your answerultiple Choice.

This is a result of changes in electron distribution; and formed when atoms combine.

a. Chemical symbolsb. Chemical bondsc. Periodic tabled. Lewis symbol

The difference between a family and a group in the periodic table is that:

a. Families are columns and groups are rowsb. Families are rows and groups are columnsc. Families determine the energy level of an element and groups determine the number of val

electronsd. None of the above

Which guideline shows that atoms tend to gain, lose, or share electrons until they are surroundeeight valence electrons.

a. Octet Ruleb. Hunds Rulec. Lewis Ruled. Formal charge

Select the term best describing the series of elements: Mn, Fe, Co, Ni, Cu.

a. d-transition metals c. mettaloidsb. representative elements d. alkaline earth metals

Which of the following properties of the alkali earth metals decreases with increasing atomic weigh

a. ionic radii b. ionization energy c. atomic radii d. atomic number

Which statement is wrong?

a. The atomic weight of carbon is about 12.

b. The most stable ion of lithium is Li+.

c. A phosphorous atom is larger than an antimony atom.d. The radius of a sodium atom is larger than that of a sodium ion.

Which element would have the higher electron affinity?

a. Cl b. Brc. Both should have the same electron affinity because they are in the same group of

the periodic table and both will gain only one electron.e. They have the same electron affinity.


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Which of the following elements has the greatest attraction for electrons in a covalent bond?a. Ge b. As c. Se d. Br

Which of the following ions has the smallest diameter?

a. O2 b. Na+ c. F d. Al3+

. Which of the following elements has the greatest electronegativity?

a. Si b. P c. N d. O

. All of the following properties of the alkali metals increase going down the group EXCEPT:

a. atomic radius b. first ionization energy c. ionic radius d. atomic mass

. Which of the following correctly describes the trend in electronegativity?

a. increases across a period and decreases down a groupb. decreases across a period and decreases down a groupc. increases across a period and increases down a groupd. decreases across a period and increases down a group

. Which one of the following is not a form of chemical bonding?

a. covalent bonding b. hydrogen bondingc. ionic bonding d. metallic bonding

. Covalent bonds are least likely to be formed

a. between atoms of the same elementb. between atoms of the different elements on the right of the periodic tablec. by head of the group element with high ionization energiesd. between an element in Group IA and an element in Group VIIA

. The smallest possible unit of a covalent bond is usually considered to be a/an

a. atom b. cation c. molecule d. polyatomic ion

. A triple bond exists when two atoms share ______ electrons.

a. two b. three c. four d. six

. Which one of the following statements about positive ions is incorrect?

a. they are also known as cationsb. they are formed when electrons are removed from atoms

c. they are larger than the atom from which they are formedd. they are smaller than the atom from which they are formed

. Which one of the following violates the octet rule?a. PCl3 b. CBr4 c. NF3 d. AsF5

. Which combination of atoms can form a polar covalent bond?

a. H and H b. H and Br c. N and N d. Na and Br. Which of the following four molecules are polar: PH3, OF2, HF, SO3?


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a. all except SO3 c. only HF and OF2b. only HF d. all are polar molecules

. Which of the following molecules is the most polar?

a. hydrogen chloride, HCl c. hydrogen molecule, H2b. hydrogen iodide, HI d. chlorine molecule, Cl2

. The neutral atoms of all of the isotopes of the same element have

different numbers of protons d. the same mass numbersequal numbers of neutrons e. the same massesthe same number of electrons. Molecules are made up from two or more ...electrons b. atoms c. . substances d. mixtures. Pick the correct statement:Atomic number is the sum of the number of protons and neutrons.Atomic number is the number of protons.The number of electrons is the atomic number of an atom.Atomic number is the same as the mass number.

. Which statement is correct?

Mass number is the sum of protons, neutrons and electrons in an atom.Mass number is the sum of protons and electrons in an atom.Mass number is the sum of protons and neutrons in an atom.Mass number is the same as the atomic number.

. Chemistry is the study of:a. substances b. mixtures c. elements d. only a and ce. all of the above are included in the study of chemistry

. Water is an example ofa. an element b. an ion c. a compound d. a mixture e. all of the

ove

. The first step of the scientific method involves:a. forming a hypothesis b. making observations c. performing an experimentd. predicting the result of an experiment e. formulating a hypothesis

. A liquid is considereda. an element b. a compound c. a state of matter d. a metal e. a

nmetal. Which answer includes all the following that are chemical changes and not physical changes?

I. freezing of waterII. rusting of iron

III. dropping a piece of iron into hydrochloric acid (H2 is produced)IV. burning a piece of woodV. emission of light by a kerosene oil lamp

a. III and IV b. II and V c. I ,II, II, IV and V d. II, III, and V e. II, III, IV, and V

. Iron is an example ofa. an element b. an ion c. a compound d. a mixture e. al

e above


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. Which type of change occurs when the size, shape, appearance, or volume of a substance is chanthout changing

its composition?a. chemical b. physical c. nuclear d. none of them

. Dissolving salt in water is an example of which type of change?

a .chemical b. physical c. nuclear d. none of them

. An example of a chemical property is

a. density b. mass c. acidity d. solubility e. temperature

. Which of the following is not a pure substance?a. molten sodium chloride b. sodium chloride solution c. sodium chloride solidd. sodium chloride vapor e. none of them

. A pattern or relationship that has been established based on a large amount of experimental data

a. theory b. hypothesis c. law d. model e. scientific meth

. The element with symbol Mn is called

a. metal b. magnesium c. sodium d. manganese e. molybdenum

. Which of the following is classified as a metal?a. Ge b. As c. F d. V e. Ar

. Which element best characterizes an organic compound?

a. Oxygen b. Carbon c. Hydrogen d. Nitrogen e. Sulfur

. Identify the INCORRECT statement.a. Helium in a balloon: an element b. Paint: a mixture c. Tap water: a compound. Mercury in a barometer: an element e. Polluted air: a homogenous mixture

. The number 10.00 has how many significant figures?a. 1 b. 2 c. 3 d. 4 e. 5

. The molecule below that is an acid isa. NaCl b. KCl c. CCl4 d. HCl e. MgCl2

. The element below which is a nonmetal isa. silicon b. sodium c. carbon d. both a and c e. a, b and c are all

nmetals

. 20 m/s is the same as:

a. 0.02 km/s b. 2000 mm/s c. 200 cm/s d. 0.002 mm/s e. 20 cm/s

. The number 0.005436 has how many significant figures?a. 7 b. 3 c. 4 d. 5 e. 6

. Two students, Joshua and NJ, determined the mass of an object on two different balances. Thecepted mass of the

object was 2.355 g. Joshua obtained values of 2.531g, 2.537 g, 2.535 g and 2.533 g. NJ obtalues o 2.350 g,

2.404 g, 2.296 g and 2.370 g. Which statement best describes the results that were obtaineJoshua and NJ?


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a. Joshua obtained the better accuracy. b. NJ obtained the better accuracy. c. Jotained the

better precision. d. NJ obtained the better precision. e. Both Joshua and NJ obtainedcuracy and

precision.

. The correct dimensional analysis for the conversion of 6.30 kilometers to miles is:

a.miles

kilometers30.6 b.

kilometers

meters30.6 c.

kilometers

miles30.6

d. miles

scentimeter

30.6 e. miles

miles

30.6

. What is the appropriate SI unit for distance?a. centimeters b. inches c. meters d. kilometers e. miles

. How many milligrams are in 0.2 decigrams?a. 20 mg b. 2000 mg c. 0.002 mg d. 0.00002 mg e. 2 mg

. Which of the following has a positive charge?a. proton b. neutron c. anion d. electron e. atom

. According to Daltons atomic theory, a compound is a unique collection ofa. like atoms b. atoms with the same atomic number c. atoms in varying proportionsd. different atom types in whole number ratios e. all of them

. Consider the species Zn72 , As75 , Ge74 . These species have the:

a. same number of electrons b. same number of protons c. same number of neutrd. same number of protons and neutrons e. same mass number

. The neutral atoms of all of the isotopes of the same element havea. different numbers of protons b. equal numbers of neutrons c. the same massesd. the same mass numbers e. the same number of electrons

. Which atom contains exactly 15 protons?

P 32 b. O 15 c. N 15 d. only a and b e. only b and c

. An ion with 5 protons, 6 neutrons, and a charge of 3+ has an atomic number of

5 b. 6 c. 8 d. 11 e. 2

. The neutral atomic particle that resides in the nucleus is thea. electron b. proton c. neutron d. nucleus e. both b and c are correct answers

. +P31 has _____ protons, _____ neutrons, and _____ electrons.

a.31, 15, 30 b.15, 31, 15 c. 15, 31, 14 d. 15, 16, 14 e. 15, 16, 16

. The number of neutrons in an atoms nucleus is given by:a. atomic number (Z) b. mass number (A) c. atomic particles in the nucd. the electrons in the nucleus e. mass number atomic number

. With regard to the species 216O , F19 and Ne20 , which of the following statements is correct?

a. All three species contain 10 electrons.b. The sum of the neutrons in all three species is 27.c. The sum of the protons in all three species is 28.

d. Both F19 and Ne20 contain 20 neutrons.


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e. none of the above. Which name/formula combination is WRONG?

a. phosphorous acid/H3PO4 b. nitrogen monoxide/NOc. acetate ion/CH3COO-

d. sodium chromate/Na2CrO4 e. calcium hypobromite/Ca(BrO)2

. An unused flashbulb contains magnesium and oxygen. After use, the contents are changed tomagnesium oxide but the

total mass does not change. This observation can best be explained by thea. Law of Constant Composition b. Law of Multiple Proportions c. Avogadros Lawd. Law of Conservation of Mass e. Boyles Law

. Which of the following choices provides the best description of an isotope?a. Atoms with the same number of protons but differing numbers of electrons.b. Atoms with the same mass number but differing atomic numbers.c. Atoms with the same mass numbers and the same atomic numbers.d. Atoms with the same atomic numbers but differing mass numbers.e. none of the above

. The cation +2Cu is best named as

a. copper (I) b. cesium (I) c. copper (II) d. copper (III) e. cesium (III)

. What is the oxidation number for carbon in 42OCaC ?

a. 0 b. +2 c. +3 d. +4 e. +6

. The identity of an element is determined bya. the number of its protons b. the number of its neutrons c. the number of its electd. its atomic mass e. all of the above

. Determine the oxidation number of carbon in 32COK .

a. 0 b. +2 c. +4 d. -2 e. some other value

. The charge on the lead atom in the compound ( )24

SOPb is

a. 0 b. +1 c. +2 c. +3 e. +4

. Which one of the formulas for ionic compounds below is incorrect?a. SrCl2 b. Cs2S c. AlCl3 d. Al3P2 e. CaSe

. Which name/formula combination is WRONG?a. chlorous acid/HClO2 b. dinitrogen tetroxide/N2O4 c. ammonium nitrate/NH4NO3d. copper (II) periodate/CuIO4 e. potassium permanganate/KMnO4

. Of the following name/symbol combination of elements, which one is WRONG?a. uranium/U b. sulfur/S c. nitrogen/N d. potassium/K e. iro

. Aluminum is in Group III. Its oxide will have the formula a. AlO b. AlO2 c. Al2O3O2 e. AL2O3

. Which of the following choices is the correct name for H2CO3?

dihydrogen carbon b. carbonic acid c. hydrogen carbon oxide d. hydrogearbon e. dihydrogen carbonate

. A student wrote the following formulas for various compounds:I. copper (I) chloride CuCl III. lead (II) hydroxide Pb(OH)2II. sodium chlorate NaClO3 IV. magnesium nitrate Mg(NO3)2


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Which of the following statements is true?a. All of the formulas are correct. b. Only formulas I, III and IV are correct.c. Only formulas I, II and III are correct.d. Only formulas II, III and IV are correct.

. Balance the molecular equation for the following redox reaction. What is the sum of the coefficieo not forget

coefficients of one (1). Use the smallest whole number coefficients possible.

H2SO4(aq) + HI(aq) I2(s) + SO2(g)

a. 7 b. 9 c. 11 d. 13 e. 5. When iron pyrite (FeS2) is heated in air, the process known as "roasting" forms sulfur dioxide and

iron(III) oxide. When the equation for this process is completed and balanced, usingthe smallest whole number coefficients, what is the coefficient for "O2"?

___ FeS2 + ___ O2 ___ SO2 + ___ Fe2O3

a. 2 b. 4 c. 7 d. 8 e. 11

. The correct name of the molecule CO2 isa. carbon oxide b. carbon dioxide c. monocarbon monoxided. monocarbon dioxide e. carbonate

. Which one of the sets below represents the correct values for the coefficients w, x, y, and z in thelowing equation?

(w) Fe(NO3)3 (x) Fe2O3 + (y) NO2 + (z) O2

w x y z

a. 2 1 6 3b. 2 2 6 3c. 4 2 3 3d. 4 2 12 3

. The number of sulfur atoms in the molecule Al2(SO4)3 isa. 0 b. 1 c. 2 d. 3 e. 4

. Which one of the following could be an empirical formula?a. C9H15N3O6 b. C14H10CuO4 c. C17H25NO3d. C8H18O3 e. All of these could be empirical formulas

. When barium sulfate is formed from the reaction of barium and sulfur trioxide, it is a/n _________action.

a. Combination b. Decomposition c. Single replacement d. Doubledisplacement e. Neutralization

. Analysis of a sample of a covalent compound showed that it contained 14.4% hydrogen and 85rbon by mass.

What is the empirical formula for the compound?a. CH b. CH2 c. CH3 d. C2H3 e. none of these

. A compound contains, by mass, 40.0% carbon, 6.71% hydrogen, and 53.3% oxygen. A 0.320 mple of this compound weighs 28.8 g. The molecular formula of this compound is:

a. C2H4O2 b. C3H6O3 c. C2H4O d. CH2O e. C4H7O2


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. Guanidin, HNC(NH2)2, is a fertilizer. To three significant figures, what is the percent by mastrogen in the fertilizer?

a. 45.2% b. 49.4% c. 54.8% d. 65.1% e. 71.1%

. How many atoms are in one mole of CH3OH?a. 6 b. 6.0 1023 c. 12.0 1023 d. 3.6 1024 e. 3

. How many aluminum atoms are there in 3.50 grams of Al2O3?a. 4.13 1022 b. 4.90 1022 c. 2.07 1022 d. 1.68 1022 e. 2.45 1022

. What is the volume of a 2.50 gram block of metal whose density is 6.72 grams per cubic centimeta. 16.8 cubic centimeters b. 2.69 cubic centimeters c. 0.0595 cubic centime

d. 0.372 cubic centimeters e. 1.60 cubic centimeters

. How many moles of KBrO3 are required to prepare 0.0700 moles of Br2 according to the reaction:

KBrO3 + 5KBr + 6HNO3 6KNO3 + 3Br2 + 3H2O

a. 0.210 b. 0.0732 c. 0.0704 d. 0.220 e. 0.0233. Calculate the mass of hydrogen formed when 25 grams of aluminum reacts with excess hydrochid.

2Al + 6HCl Al2Cl6 + 3H2

a. 0.41 g b. 1.2 g c. 1.8 g d. 2.8 g e. 0.92 g

. When 12 g of methanol (CH3OH) was treated with excess oxidizing agent (MnO4-), 14 g of formicacid (HCOOH) was obtained. Using the following chemical equation, calculate thepercent yield. (The reaction is much more complex than this; please ignore the fact thatthe charges do not balance.)

3CH3OH + 4MnO4- 3HCOOH + 4MnO2

a. 100% b. 92% c. 82% d. 70% e. 55%. If 5.0 g of each reactant were used for the the following process, the limiting reactant would be:

2KMnO4 + 5Hg2Cl2 + 16HCl 10HgCl2 + 2MnCl2 + 2KCl + 8H2O

a. KMnO4 b. HCl c. H2O d. Hg2Cl2 e. HgCl2

. Silicon carbide, an abrasive, is made by the reaction of silicon dioxide with graphite.

SiO2 + 3C SiC + 2CO

If 100 g of SiO2 and 100 g of C are reacted as far as possible, which one of the followingstatements will be correct?

a. 111 g of SiO2 will be left over. b. 44 g of SiO2 will be left over.c. 82 g of C will be left over. d. 40 g of C will be left over.

e. Both reactants will be consumed completely, with none of either left over.

. The limiting reagent in a chemical reaction is one that:a. has the largest molar mass (formula weight).b. has the smallest molar mass (formula weight).c. has the smallest coefficient.d. is consumed completely.e. is in excess.

. What is the molarity of phosphoric acid in a solution labeled 20.0% phosphoric acid (H3PO4)weight with a density = 1.12 g/mL?


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a. 0.98 M b. 2.3 M c. 2.7 M d. 3.0 M e. 3.6 M

. What Kelvin temperature is equal to 25C?

a. 248 K b. 298 K c. 100 K d. 200 K e. 273 K

. Thirty (30) mg is the same mass as:

a. 300 dg b. 0.3 grams c. 0.0003 kg d. 0.03 g e. 3OO cg

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