Name__________________________________________ Date____________ Period________

Chemistry Mid-Year ReviewRead ALL the problems. Complete as many as you feel necessary for you exam preparation. Concentrate on the ones you do NOT know how to do. There are some occasional references to ions or compounds that were outside of the scope of our particular class. Feel free to look up / access internet / use other resources to complete. The answers provided below are NOT guaranteed. Please email me if you find an error.

Unit 1 1. What are the steps of the scientific method?

:a process to identify and prove the cause and effect relationship between an independent and a dependent variable. Often it involves and observation/question, a hypothesis, an experimental design/procedure, the collection and analyzing of data, and making a conclusion.

2. What is an experimental control?: a test group or set-up which has predictable results / used for comparison

3. What is a controlled variable?: a condition that could affect the results that is held constant during the

experiment4. What is difference between an independent variable and a dependent variable?

: the independent variable is the cause (purposefully change/manipulated) while the dependent variable is the measured effect.

5. What is the difference between qualitative data and quantitative data?: qualitative is a relative observation; whereas quantitative is a numerical

observation6. Determine the correct number of significant digits for the figures below and write each number in scientific notation

a) 0.93 2 b) 1.008 4c) 340 2 d) 10001 5e) 0.097 2 f) 15.96 4g) 39.5 3 h) 10100 3

7. Add or subtract the following numbers. Round to the correct amount of significant digits and scientific notation

a) 7.623 + 85.0+ 9.815 =102.4 b) 10.96 – 5.555 =5.4c) 230.72 + 0.00861 =230.73 d) 9.0731 + 0.00078 =9.0739e) 10.96 – 5.5 =5.5 f) 23.6 – 16.1218 =7.5

8. Multiple or Divide the following measured numbers. Round to the correct amount of significant digits and scientific notation NOTE: b and d were intended as scientific notation, please correct on your copy.

a) 2.695 x 33.20 x 1.5611 =139.7 b) (3.2 x 103)(4.21 x 102)÷ 6.28 x 10-8 =2.15 x 1013

c) 8.032/0.591 =13.6 d) (2.500 x 106)(3.92 x 10-3) =9.80 x 103

e) (72.21 x 6.42) + 7.050 =53.3 f) (6000260 x 0.005201) ÷ 5.206 = 3.121 x 104

9. Answer the questions below using the figures provided.

a. What is the reading of the water level in the test tube? 18.0 mLb. What is length of the ruler at point G? Point E? Point B? Point J? Point F?

G = 9.67cm E = 10.30cm B = 11.30cm J = 11.70cm F = 12.00 cm (MUST measure to 1/100ths, values +/- a hundredth or two are acceptable)

10. Solve the follow dimensional analysis problems. Solve all problems using scientific notation and significant digits

a. 3 m = 3 x 102 cm b. 1 cm = 1 x 10-4 μmc. 20 mm = 2 cm d. 1 m = 1 x 10-3 km-. 15g = 1.5 x 103 mg f. 2 L = 2 x 103 mL

11. What is a significant figure?: is any number in a measurement that is certain (compared to a standard) PLUS one estimated value. 12. a. What is an element?

:a pure substance that cannot be broken down into simpler substances by chemical means. b. What is a compound?

:a pure substance that can be broken down into simpler substances by chemical means. c. What is a substance?

:a material that cannot be separated into simpler substances by physical means.

d. What is an atom?: the smallest particle that retains its chemical identity (protons/neutrons and

electrons do NOT!)13. Answer the following questions about density.

a. What is density, and what is the mathematic equation used to find the density of a substancedensity = Mass / VolumeCalculate the following densities. Use Significant Digits in your answer. b. 252 mL of a solution with a mass of 500 g = 1.98g/mLc. A 6.75 g solid with a volume of 5.35 cm3 = 1.25 g/cm3

d. 50.0 mg of a gas which occupies a volume of 0.0064 L = 7.8 x 10-3g/mL 14. What is Accuracy? What is precision? How do they differ when speaking about them in scientific terms.Accuracy is how close a measurement is to the true or known value and is expressed in percent error. Precision is how repeatable/reproducible a measurement is and is expressed as range or deviation.15.

a. Working in the laboratory, a student find the density of a piece of pure aluminum to be 2.85 g/cm3.  The accepted value for the density of aluminum is 2.699 g/cm3.  What is the student's percent error? = 5.59%

b.  A student experimentally determines the specific heat of water to be 4.29 J/g x Co.  He then looks up the specific heat of water on a reference table and finds that is is 4.18 J/g x Co.    What is his percent error? = 2.63%

c.  A student takes an object with an accepted mass of 200.00 grams and masses it on his own balance.  He records the mass of the object as 196.5 g.   What is his percent error? = -1.750%

16. Precision ProblemsSeveral lab groups measure the density of aluminum. Here is their data:

Team 1 Team 2 Team 3 Team 4 Team 5 Team 6 Team 72.65

g/cm32.75

g/cm32.80

g/cm32.77

g/cm32.60

g/cm32.65

g/cm32.68

g/cm3

a. What is the average density? 2.70 g/cm3

b. Subtract the highest value from the lowest value: 0.20 g/cm3 Divide this number by 2 0.10 g/cm3

c. The precision of the measurement can be shown as 2.70 0.10 g/cm3.d. Here is more data. Is this more precise, less precise, or the same precision

as the above data? The same.Team 1 Team 2 Team 3 Team 4 Team 5 Team 6 Team 7

2.60 g/cm3

2.70 g/cm3

2.80 g/cm3

2.75 g/cm3

2.65 g/cm3

2.62 g/cm3

2.78 g/cm3

Unit 217. The Periodic Table

a. A proton has a +1/positive charge, a neutron has a 0/neutral charge, and an electron has a -1/negative charge

b. Group 2A (column 2) has a charge of +2c. Group 6A (column 16) had a charge of -2d. An element with a positive or negative charge is called an ione. An ion with a negative charge is called an anionf. An ion with a positive charge is called a cationg. An ionic bond is the transfer of electrons and a covalent bond is a sharing of

electrons18. Label each of the sections of the element below

Atomic Number (Number of Protons)

Chemical Symbol

Atomic Mass (Average of ALL Isotopes)Mass Number is the sum of protons +

neutrons

19. Fill out the following table based on the information given. Use your periodic table to help complete it.

Element Atomic # Atomic Mass

Charge # of protons

# of neutrons

# of electrons

Lithium 3 7 +1 3 4 3

Nitrogen 7 14 0 7 7 7

Fluorine 9 19 -1 9 10 10

Argon 18 40 0 18 22 18

Tarbium 65 159 +2 65 94 63

Naming Compounds – Ionic and Covalent20. Name the following chemical compounds. a. CaF2

calcium fluoride b. NaF sodium fluoride

c. P2O3

diphorphorus trioxided. MgSO4

magnesion sulfate

e. AgNO3 f. C2S7

silver nitrate dicarbon heptasulfideg. Al2(CO)3

aluminum carbonateh. SrS strontium sulfide

i. NaBr sodium bromide

j. NaOH sodium hydroxide

k. H2SO4

sulfuric acidl. MgI2 magnesium iodide

m. NH3

ammonian. CaNO2

calcium nitritro. Ti(SO4)2

titanium (IV)sulfatep. N3O8

trinitrogen octoxideq. SO2

sulfur dioxider. Na2O sodium oxide

s. NaNO3

sodium nitratet. BF5

boron pentafluoride

21. Give the correct formula for the following compoundsa. disilicon tetraselenide Si2Se4 b. cobalt (II) chloride CoCl2

c. copper (I) acetate CuC2H3O2 d. lithium phoshide Li3P

e. sodium fluoride NaF f. manganese (IV) nitride Mn3N4

g. iron (III) sulfite Fe2(SO3)3 h. boron trichloride BF3

i. silver oxide Ag2O j. carbon tetraarsenide CAs4

k. strontium carbonite SrCO2 l. beryllium astatide BeAt2

m. pentasilicon dichloride Si5Cl2 n. nickel (II) selenide NiSe

o. potassium permanganate KMnO4 p. cesium carbonate Cs2CO3

q. sodium hydroxide NaOH r. ammonia hydroxide NH4OH

s. tetraphosphorus octatelluride P4Te8 t. calcium iodide CaI2

22. Calculate the Molar Mass of the following compounds.a. Cu(CN)2 = 116.0 g/mol b. C6H6 =78.0g/mol c. SmO = 166.4g/mol

d. H3PO4 = 98.0g/mol e. K2SO4 = 174.3g/mol f. ZnO = 81.4g/mol

g. (NH4)3PO3 = 133.0g/mol h. BaCO3 = 197.3g/mol i. NaHCO3 = 84.0g/mol

23. Calculate the Percent Composition of the following elements

a. Nitrogen in Cu(CN)2 = 24.1%

b. Carbon in C6H6 = 92.3%

c. Oxygen in SmO = 90.4%

d. Phosporus in H3PO4 = 30.7%

e. Oxygen in K2SO4 = 36.7%

f. Zinc in ZnO = 80.3%

g. Complete Percent Composition in (NH4)3PO3

=31.6%N,9.0%H,22.6%P,36.1%O

h. Complete Percent Composition in BaCO3

= 69.6%Ba, 6.1%C, 24.3%O

i. Complete Percent Composition in NaHCO3

=27.3%Na1.2%H,14.3%C,57.1%O

24. a. What is the definition of Avogadro’s numberAvogadro’s number is the number of atoms in exactly 12.0 grams of carbon

12 isotope.b. What does STP stand for, and what are the measurements for each

STP means standard temperature of 0o C and pressure of 1 atm c. How many moles are in 521 grams of HCl = 14.3 mole HCld. How many atoms are in 41 grams of K = 6.3 x 10 23atoms Ke. How many Liters of O2 gas are in 35 grams = 24.5 L O2

f. How many grams of CO2 gas are in 245 Liters = 481 g CO2

g. How many moles are in 51 x 1026 molecules of HNO3 = 8.4 x 103 moles HNO3

h. How many grams are in 4.7 moles of H2CO3 = 290 g H2CO3 (rounded for sig fig from 291.4)

i. How many molecules are in 72.3 Liters of NH3 gas = 1.94 x 1024 molecules NH3

j. How many moles are in 83 Liters of Cyanide gas = 3.7 mol CNk. How many grams are in 11.9 x 1021 atoms of Kr = 1.66 g Kr

25. Figure out the empirical formulas for each of the following compoundsa. A compound that is 25.41g S and 38.11g O SO3

b. A compound that has 1.04g K, 0.700g Cr, and 0.86g O K2CrO4

c. A compound that is 53.7% Fe and 46.30% S Fe2O3 (from Fe1O1.5)d. A compound that has 4.04g of N and 11.16g of oxygen P2O5 (from P1O2.5)e. 43.67% P and 56.33% O P2O5 (from P1O2.5)f. 39.3% Na and 60.7%Cl NaClg. 24.58% K, 34.81% Mn, and 40.50% O KMnO4

Unit 3 26. What is the definition of a physical property, chemical property, and chemical reactions? Give 3 examples of physical changes? Give 3 examples of chemical changes?A physical property is observed with senses and the act of observing it does NOT change the chemical make up of the material. A chemical property is observed by reaction the material with another substance and the act of observing it produces a new chemical substance. Examples of physical change may be grinding, melting,

cutting, boiling, etc. Examples of chemical change may be rusting/oxidizing, burning/combusting, reacting with acid or bases, etc.27. What is a reactant? Which side of the equation are the reactants on?

Reactants are the substances that exist before the reaction. They are listed on the left side.28. What is a product? Which side of the equation are the products on?

Products are the substances that exist after the reaction. They are listed on the right side.29. Is the mass of the reactants equal to, greater than, or lesser than the mass of the products?

The Law of Conservation of Mass says the mass of the reactants is always EQUAL to the mass of the products. This is because the number and type of atoms before the reaction are the same after the reaction; the bond are broken, the atoms are rearranged and new bonds are formed. (The Law of Conservation of Matter).

30. What is a coefficient? What is subscript? What do each signify and where are they located in a problem?

A coefficient tells how many molecules, where a subscript tells how many atoms in ONE molecule. (See example below).

31. Give examples of a coefficient and of a subscript.3H2O The 3 is a coefficient; it means 3 water molecules.

The 2 is the subscript; it means 2 hydrogen atoms in EACH of the 3 water molecules.

32. Answer the following questions below. a. 5 Al2CO3 How many molecules? 5 How many atoms of Aluminum? 10

How many atoms of Carbon? 5How many atoms of Oxygen 15

b. CH3COOH How many molecules? 1 How many Atoms of Hydrogen? 4

How many atoms of Carbon? 2How many atoms of Oxygen? 2

c. 4 (NH4)3PO3 How many molecules? 4 How many Atoms of Nitrogen? 12

How many atoms of Hydrogen? 48How many atoms of Phosphorus? 4How many atoms of Oxygen? 12

33. First, write out the following word equations. Second, write the formula equations. Lastly, balance the equations and make sure to indicate which state/phase each is in!a. Carbon gas and Nitrogen gas combine to form cyanide gas

carbon + nitrogen cyanide Steps: C + N2 CN C + N2 2CN 2C + N2 2CN

Finished balanced equation with phase notations:

2C(g) + N2(g) 2CN(g)

b. Liquid pentane and Oxygen gas combine to make Carbon Dioxide gas and Water pentane + oxygen carbon dioxide + water C5H12(g) + 8O2(g) 5CO2(g) + 6H2O(g)

c. Salt is broken down to form Sodium metal and Chlorine gas sodium chloride sodium + chlorine 2NaCl(s) 2Na(s) + Cl2(g)

d. Hydrogen gas and Oxygen gas form Water when bonded together. hydrogen + oxygen water 2H2(g) + O2(g) --> 2H2O(l)

e. Aqueous Copper Chloride combines with aqueous Sodium Sulfate to form Aqueous Copper Sulfate and Sodium Chloride.

Copper (I) would be: copper(I) chloride + sodium sulfate copper(1) sulfate + sodium chloride 2CuCl (aq) + Na2SO4(aq) Cu2SO4(s) + 2NaCl(aq)

Copper (II) would be: copper(II) chloride + sodium sulfate copper(II) sulfate + sodium chloride

CuCl2 (aq) + Na2SO4(aq) CuSO4(s) + 2NaCl(aq)

34. Balance the following equations

35. Balance the following equations and identify the type of reaction showna. 2Al + 2H3PO4 2AlPO4 + 3H2 TYPE Single Replacementb. NH4Cl + NaNO3 NaCl + 2H2O + N2O TYPE Double

a.

2Fe + 3H2SO4 Fe2(SO4)3 +

3H2

b.

2C2H6 + 7O2 6H2O +

4CO2

c.

3KOH + H3PO4 K3PO4 +

3H2O

d.

SnO2 + 2H2 Sn +

2H2O

e.

4NH3 + 5O2 4NO +

6H2O

f. 2KNO3 + H2CO3 K2CO3 +

2HNO3

g.

B2Br6 + 6HNO3 2B(NO3)3 +

6HBr

h.

2BF3 + 3Li2SO3 B2(SO3)3 +

6LiF

i. 4(NH4)3PO4 + 3Pb(NO3)4

Pb3(PO4)4 +

12NH4NO3

j.

SeCl6 + O2 SeO2 +

3Cl2

/Decompostionc. 5Cl2 + 10NaOH 8NaCl + 2NaHClO3 + 4H2O Type(Not able to discern)d. 2Pb(NO3)2 2PbO +4NO2 +O2 TYPE Decompositione. 2C3H8 + 7O2 6CO +8H2O TYPE Incomplete Combustionf. 2KI + Cl2 2KCl + I2 TYPE Single Replacementg. CO2 + C 2CO TYPE Synthesish. 3H2O + P2O5 2H3PO4 TYPE Synthesisi. CaSO4 + Na2CO3 CaCO3 + Na2SO4 TYPE Double Replacementj. H2SO4 + 2 KOH K2SO4 + 2H2O TYPE Double Replacement

36. Write It, Balance it, Identify it!!!a. potassium iodide + chlorine potassium chloride + iodine TYPE Single Replacement 2KI + Cl2 2KCl + I2b. sulfuric acid + potassium hydroxide potassium sulfate + dihydrogen monoxide TYPE Double Replacement H2SO4 + 2 KOH K2SO4 + 2H2Oc. carbon dioxide + carbon carbon monoxide TYPE Synthesis CO2 + C 2COd. calcium sulfate + sodium carbonate calcium carbonate + sodium sulfate TYPE Double Replacement CaSO4 + Na2CO3 CaCO3 + Na2SO4

e. water + diphosphorous pentoxide phosphorous acid TYPE Synthesis 3H2O + P2O5 2H3PO4 f. aluminum + phosphoric acid hydrogen + aluminum phosphate TYPE Single Replacement 2Al + 2H3PO4 3H2 + 2AlPO4

g. ammonium chloride + sodium nitrite sodium chloride + water + N2O TYPE Double /Decompostion NH4Cl + NaNO3 NaCl + 2H2O + N2O h. chlorine + sodium hydroxide sodium chloride + sodium hypochlorite + water TYPE (Not able to discern) 5Cl2 + 10NaOH 8NaCl + 2NaHClO3 + 4H2O i. lead (II) nitrate -- (heated) lead (II) oxide + nitrogen dioxide + oxygen TYPE Decomposition 2Pb(NO3)2 2PbO +4NO2 +O2

j. propane + oxygen carbon monoxide + dihydrogen monoxide TYPE Incomplete Combustion 2C3H8 + 7O2 6CO +8H2O 37. What is an activity series and how does it help us? Ranks the activity of metals (and Hydrogen) for cationic single replacement reactions and separately for non metals for anionic signle replacement reactions. This allows one to predict whether a single replacement reaction is spontaneous or not.38. Use the activity series provided, predict which of the

following reactions will occur. (Yes or No answer) a.) Ag + ZnCl2 Nob.) Zn + AgNO3 Yesc.) NaCl + I2 Nod.) K + CaO Yese.) Mg + HCl Yes

39. Predict the products and balance the equation for those reactions that do occur in #38.38b: Zn + 2AgNO3 2Ag + Zn(NO3)2

38d: 2K + CaO Ca + K2O