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Name_____________________________________________________________________ CHEMISTRY 1 REVIEW CHEMICAL FOUNDATIONS Significant Figures and Unit Conversions 1) How many significant figures are in each of the following? 1

d) 0.0048

2

b) 1.00 x 10

3

e) 0.00480

3

c) 100.

3

f) 2303.03

6

a) 100 2

2) Round off each of the following numbers to the indicated number of significant figures, and write the number in standard scientific notation. 3.42x10-4 a) 0.00034159 to three sig figs b) 103.351 to four sig figs

1.034x102

c) 17.9915 to 5 sig figs

1.7992x101

d)3.365 x 105 three sig figs

3.37x105

3) Use exponential notation to express the number 385,500 to a) 1 sig fig

4x105

b) 2 sig figs

3.9x105

c) 3 sig figs

3.86x105

d) 4 sig figs

3.855x105

4) Perform the following mathematical operations, and express the result to the correct number of significant figures. 788.15 a) 2.526/3.1 + 0.470/0.632 + 80.705/0.4326 b) (6.404 x 2.91) / (18.7 – 17.1) -5

-6

12 -4

c) 6.071 x 10 - 8.2 x 10 – 0.521 x 10

4.100x10-7

d) 8.925 -8.905 X 100 (percent error calculation, assume 100 is an exact number) 0.224 8.925 For #5-8, must show all work using dimensional analysis! Express answers with correct units and significant figures. 5) Science fiction often uses nautical analogies to describe space travel. If the starship U.S.S. Enterprise is traveling at warp factor 3.42, what is its speed in knots and in miles per hour? (1.71 warp = 5.00 times the speed of light; speed of light = 3.00 x 108 m/s; 1 knot = 2030 yd/h, 5280 feet = 1 mile, 1m = 3.3 ft, 1760 yd = 1 mi). 6.75x109 mph 5.85x109 knots 6) You pass a road sign saying “New York 112 km”. If you drive at a constant speed of 65 mi/h, how long should it take for you to reach New York? If your car gets 28 miles to the gallon, how many liters of gasoline are necessary to travel 112 km (1609m = 1 mi, 1 gal = 3.8L)? 1.1 hr 9.5 L 7) Mercury poisoning is a debilitating disease that is often fatal In the human body, mercury reacts with essential enzymes leading to irreversible inactivity of these enzymes. If the amount of mercury in a polluted lake is 0.4 micrograms Hg per mL, what is the total mass in kilograms of mercury in the lake? (The lake has a surface area of 100 mi2 and an average depth of 20 ft.) (1ml = 1x10-6 m) 1.2z10-22 kg 8) Lipitor, a pharmaceutical drug that has been shown to lower “bad” cholesterol levels while raising “good” cholesterol levels in patients taking the drug, had over 11 billion dollars in sales in 2006. Assuming one 2.5 g pill contains 4.0 % of the active ingredient by mass, what mass in kg of active ingredient is present in one bottle of 100 pills? 0.010 kg

Density 9) A rectangular block has dimensions 2.9 cm x 3.5 cm x 10.0 cm. the mass of the block is 615.0 g. What are the volume and density of the block? (Show all work, express answer with correct sig figs and unit) 102 cm3 6.06 g/cm3 Classification/Separation of Matter 10) Classify each of the following as a mixture or a pure substance. Of the pure substances, which are elements and which are compounds? e) brass mixture a) water pure, cpd b) blood

mixture

f) uranium

pure, element

c) the oceans

mixture

g) wine

mixture

d) iron

pure, element

h) table salt

pure, cpd

11) Classify the following as physical or chemical changes: a) Moth balls gradually vaporize in the closet phys b) HF acid attack glass and is used to etch calibration marks on glass laboratory utensils.chem c) Chemistry major sometimes get holes in the cotton jeans they wear because of acid spills. chem d) A cup of tea becomes sweeter as sugar is added to it. phys ATOMS, IONS, AND MOLECULES Dalton’s Atomic Theory 12) Two elements, R and Q, combine to form two binary compounds. In the first compound, 14.0 g of R combines with 3.00 g of Q. In the second compound, 7.00 g of R combines with 4.50 g of Q. Show that these data are in accord with the law of multiple proportions. If the formula of the second compound is RQ, what is the formula of the first compound?

13) Write the atomic symbol for each of the following isotopes: a) Z = 8, number of neutrons = 9 b) the isotope of chlorine in which A = 37 c) Z = 27, A = 60 d) number of protons = 26, number of neutrons = 31 e) the isotope of I with a mass number of 131 f) Z = 3, number of neutrons = 4

14. Complete the following table:

Nomenclature 3 15) Name the following compounds: a) MgSO4 magnesium sulfate

i) HCN (aq) cyanic acid

b) Fe2O3 iron (III) oxide

j) HBr (aq) hydrobromic acid

c) N2O3 dinitrogen trioxide

k) NaHCO3 sodium bicarbonate

d) NH3 ammonia

l) HIO3 (aq) iodic acid

e) KMnO4 potassium permanganate

m) P4O6 tetraphosphorous hexoxide

f) Cr(OH)3 chromium hydroxide

n) BF3

boron triflouride

g) ZnCO3 zinc carbonate

o) LiH

lithium hydride

h) AgNO3 silver nitrate

p) K2Cr2O7 potassium dichromate

16) Write formulas for the following compounds a) sulfur trioxide SO3

j) iron (II) chlorite Fe(ClO2)2

b )lead (II) nitrate Pb(NO3)2

k) sodium hydrogen sulfate NaHSO4

c) potassium chlorate KClO4

l) carbonic acid H2CO3

d) ammonium phosphate(NH4)3PO4

m) chromium hexafluorideCrF6

e) hydrosulfuric acid H2SO4

n) ammonium oxalate (NH4)2C2O4

f) diphosphorus pentoxide P2O5

o) barium chloride BaCl2

g) iron (III) chloride FeCl3

p) potassium bicarbonate KHCO3

h) nickel(II)chloride hexahydrate NiCl2•6H2O

q) potassium hydroxide KOH

i) acetic acid HC2H3O2

r) calcium hydroxide Ca(OH)2

STOICHIOMETRY Must show all work for all problems in this stoichiometry section. Express answers with correct units and significant figures. Average Atomic Mass 19) A noble gas consists of three isotopes of masses of 19.99 amu, 20.99 amu, and 21.99 amu. The relative abundances of these isotopes are 90.92%, 0.257%, and 8.82% respectively. What is the average atomic mass of this noble gas? What noble gas is this? 20.2 amu Ne

20) The element Europium exists in nature as 2 isotopes: 151Eu has a mass of 150.9196 amu, and 153Eu has a mass of 152.9209 amu. The average atomic mass of Europium is 151.96 amu. Calculate the relative abundances of the two Europium isotopes. 48.01% -151 51.99% -153

Moles and Molar Masses 21) A diamond contains 5.0 x 1021 atoms of carbon. What amount (moles) of carbon and what mass (grams) of carbon are in this diamond? 8.3x10-3 mol 0.10 g

22) What amount (moles) is represented by each of these samples? a) 150.0 g of iron (III) oxide 0.9393 mol

b) 10.0 mg of nitrogen dioxide 2.17x10-4 mol

c) 2.7 x 1023 molecules of ethanol OMIT

23)

a) Calculate the molar mass of sodium hydrogen phosphate 142 g/mol b) What mass of sodium hydrogen phosphate is present in 5.00 moles of the compound? 710 g c) What number of formula units is present in 1.00 g of sodium hydrogen phosphate? 4.24x1021 fu

d) What number of phosphorus atoms is present in 1.00 g of sodium hydrogen phosphate? OMIT

24) Dimethylnitrosamine, (CH3)2N2O, is a carcinogenic (cancer causing) substance that may be formed in foods, beverages, or gastric juices from the reaction of nitrite ion (used as a food preservative) with other substances. a) What is the molar mass of dimethylnitrosamine? 74 g/mol

b) How many moles of dimethylnitrosamine molecules are present in 250 mg dimethylnitrosamine? 3.4x10-3 mol

c) What is the mass of 0.050 mole of dimethylnitrosamine? 3.7 g

d) How many atoms of hydrogen are in 1.0 mole of dimethylnitrosamine? 6.02x1023 atoms

e) What is the mass of 1.0 x 106 molecules of dimethylnitrosamine? 1.2x10-16g

Percent Composition 25) Calculate the mass percent of each element in potassium dihydrogen phosphate. 28.7% K 1.5% H 22.8% P 47.1% O Empirical and Molecular Formulas 26) Vanillin is often used in the production of vanilla extract, Vanillin contains the following percentages by mass: C = 63.18 %, H = 5.26 %, O = 31.56% Determine the empirical formula of vanillin. C8H8O3

27) A compound is found, by mass spectral analysis, to contain the following percentages of elements by mass: C = 49.97 %, Cl = 48.92%, H = 1.39 % The molar mass of the compound is 289.9 g/mole. Determine the empirical and molecular formulas of the compound. CH3Cl C12H4Cl4

Writing and Balancing Chemical Equations 28) Balance the following equations, then classify each reaction as either synthesis, decomposition, single replacement, double replacement, or combustion: (a) _1_N2 (g) + _3_H2 (g) → _2_NH3(g)

S

(b) _2_Li (s) + _2_H2O (l) →_2_LiOH (aq) + __H2 (g)

SR

(c) _2_KClO3 (s) → _2_KCl (s) + _3_O2 (g)

D

(d) _2_C6H14 (g) + _13_O2 (g) → _12_CO2 (g) + _14_H2O (g)

C

(e) __H2SO4 (aq) + _2_NaOH (aq) → __Na2SO4 (aq) + _2_H2O (l)

DR

29) Complete and balance the following reactions, also classify each reaction (a) calcium (s) + nitrogen (g) S (e) sodium chlorate (s) D 2Ca + N2 → 2CaN

NaClO3 → Na+ + ClO3 -

(b) C2H8 (g) + oxygen (g) C

(f) barium oxide (s) + water (l) S

C2H8 + 3O2 → CO2 + 4H2O

BaO + H2O → Ba(OH)2

(c) bromine (l) + potassium iodide (aq) SR

(g) magnesium carbonate (s) D

Br2 + 2KI → 2KBr + I2

MgCO3 → Mg+ + CO3 -

(d) cupric (II) chloride (aq)+sodium sulfide (aq)

(h) zinc (s) + hydrochloric acid (aq) SR

DR

2Zn + 2HCl → 2ZnCl + H2 CuCl2 + Na2S → 2NaCl + CuS

Reaction Stoichiometry (Again, make sure you show all work and express answers with correct sig. figs and units) 30) DDT, an insecticide harmful to fish,birds, and humans, is produced by the following reaction: 2C6H5Cl + C2HOCl3 → C14H9Cl5 + H2O chlorobenzene chloral DDT In a government lab, 1142 g of chlorobenzene is reacted with 485 g of chloral. a) Which reactant is limiting? Which is excess? C6H5Cl C2HOCl3

b) What mass of DDT is formed, assuming 100% yield? 1166.3 g

c)

What mass of the excess reactant is left over? 401 g

d) If the actual yield of DDT is 200.0 g. what is the percent yield? 17.1%

31) Consider the unbalanced reaction: P4 (s) + F2 (g) → PF3 (g) What mass of fluorine gas is needed to produce 120. g of PF 3 if the reaction has a 78.1 % yield? 6.07 g...