Chem Final Review

Pure Substances and MixturesWhat is the difference between a pure substance

and a mixture?

What are the two types of mixtures?

Which type of mixture are these?

Pure substance is made of one substance and a mixture is a combination of two of more substances

Heterogeneous- made of two different phases of matterHomogeneous- made of one phase of matter; solution

Homogeneous

Heterogeneous

The ATOMEleme

nt Symbol

Element Name

Mass Numb

er

# of p+

# of n0 # of e-

Cl-35 Chlorine 35 17 18 17

Mn-55 Manganese

55 25 30 25

K-42 Potassium 42 19 23 19

Si-26 Silicon 26 14 12 14

Element

Symbol

Element Name

Mass Numbe

r

# of p+

# of n0 # of e-

Cl-35

Mn-55

K-42

Si-26

Calculating Atomic MassCalculate the atomic mass:

Atomic mass= (23.985)(0.7870) (24.986)(0.1013) +(25.983)(0.1117)

24.31 amu

Significant Figures (sig-figs)• The number of digits reported in a

measurement reflect the accuracy of the measurement and the precision of the measuring device.

• Report the fewest significant figures

• Fewest number for multiplication and division

• Fewest decimal places for addition and subtraction

Significant Figures (sig-figs)• Non-zero numbers (e.g. 1, 2, 3…9) are

significant.• Zeros between non-zero numbers are

always significant. (e.g. 204 ml) (the sandwich rule)

• Zeros before the first non-zero digit are not significant. (e.g. 0.0003 has one.)

• Zeros at the end of the number after a decimal place are significant. (e.g. 123.00 g)

• Zeros at the end of a number before a decimal place are ambiguous (e.g. 10,300 g).

Periodic Table GroupsName special names for these sections of the

table:AB

C

F

ED

A: Alkali metalsB: Alkaline Earth metalsC: Transition metals

D: HalogensE: Nobel GasesF: Inner Transition metals

Metals, Non-metals, and MetalloidsWhat are the properties of metals?

What are the properties of non-metals?

What is a semiconductor?

Malleable, Ductile, Lustrous, Good Conductors

Dull, Brittle, and Insulators

Metalloid material that can conduct electricity

Periodic Table TrendsPut these elements in order of decreasing

Atomic radius:Al, Ag, Au, Ba, Sr

Put these ions in order of increasing Ionic Size:Br-

, O2-, N3-, Cl-, F-

Put these elements in order of decreasing electronegativity:Br, Rb, B, Li, F

Ba, Sr, Au, Ag, Al

F-, O2-, N3-, Cl-, Br-

F, Br, B, Li, Rb

Types of Chemical ReactionsWhat are the 5 types of chemical reactions?

1) Synthesis2) Decomposition3) Single

Replacement

4) Double Replacement

5) Combustion

H2 + O2 ®

H2O ®Zn + H2SO4 ®HgO ® KBr +Cl2 ®

AgNO3 + NaCl ®

Mg(OH)2 + H2SO3 ®

Synthesis

Decomposition

Single Replacement

Decomposition

Single Replacement

Double Replacement

Double Replacement

Dynamic EquilibriumLook at the following reaction at equilibrium:

H2(g) + I2(g) <===> 2HI (g)

What will adding H2(g) do the concentration of HI(g)?

What will removing I2(g) do to the concentration of HI(g)?

HI(g) will increase in concentration

HI(g) will decrease in concentration

Radioactive DecayWhat are the 3 types of radioactive decay?Which is most dangerous to living things?

What type of radioactive decay is this?

What is missing from this equation?

Alpha, Beta, and Gamma decay

Beta decay

Calculating Half-Life131I has a half-life of 8.04 days.

Assuming you start with a 1.53 mg sample of 131I, how many mg will remain after 13.0 days __________ ?

Nt = N0 x 0.5(y)Nt= 1.53mg x 0.5(13.0/8.04) Nt= 0.499

Lewis Dot StructuresDraw the Lewis Dot structure for the

following: Al, Cl, B, O, NaCl, O2

Compound NamingName for following

compounds:1) MgO2) AlS3

3) N2O5

4) Na3PO4

5) Mg(OH)2

6) (NH4)2 Cr2O7

7) K2SO3

8) CrPO4

9) Fe2 (SiO3)3

10)Hg(C2H3O2)2

1)Magnesium oxide2)Aluminum sulfide3)Dinitrogen Pentoxide4)Sodium phosphate5)Magnesium hydroxide6)Ammonium

dichromate7)Potassium sulfite8)Chromium (III)

phosphate9)Iron (III) silicate10)Mercury (II) acetate

Compound Naming IIWrite the formula for following

compounds:1) Gold (III) cyanide2) Calcium hydrogen carbonate3) Strontium nitrate4) Carbonic acid5) Calcium chloride septahydrate6) Sulfurous acid7) Lead (IV) phosphite8) Lithium chlorite9) Magnesium hypochlorite10)Beryllium perchlorate

1)Au(CN)3

2)Ca(HCO3)2

3)Sr(NO3)2

4)H2CO3

5)CaCl2 ∙ 7H2O6)H2SO3

7)Pb3(PO3)4

8)LiClO2

9)Mg(ClO)2

10)Be(ClO4)2

Electron ConfigurationsWhat are the principle quantum energy levels

and sublevels? How many orbitals in each sublevel?

Write the full electron configuration for Iodine:

Write the abbreviate electron configuration for Ra+2:

n= 1, 2, 3, 4, 5, 6, 7s= 1 orbitals p= 3 orbitalsd= 5 orbitals f= 7 orbitals

1s2 2s22p6 3s23p6 4s23d104p6

5s24d105p5

[Rn]

Molecular StructuresName the molecular structure for the following

and list the number of lone pairs and bonds:1) CO2

2) NH3

3) SeF6

4) CH4

5) H2O

6) SO2

7) PCl5

8) SO3

9) PCl3

1)2, 0; Linear; 1802)3, 1; Trigonal pyramidal;

1073)6, 0; Octahedral; 904)4, 0; Tetrahedral; 109.55)2, 2; Bent; 1056)2, 1; Bent; 1207)5, 0; Trigonal bypyrmidal;

90, 1208)3, 0; Trigonal planar; 1209)3, 1; Trigonal pyramidal;

107

Stoichiometry Determine the number of moles of N2O4 needed

to react completely with 3.62 mol of N2H4for the reaction

2 N2H4(l) + N2O4 (l) → 3 N2(g) + 4 H2O(l)

A sample of a substance is determined to be composed of 0.89 grams of potassium, 1.18 grams of chromium, and 1.27 grams of oxygen. Calculate the empirical formula of this substance. 

3.62 mol N2H4

2 mol N2H4

1 mol N2O4

= 1.81 mol N2O4

Mol K= 0.89 g/39 g = 0.02 mol KMol Cr= 1.18 g/ 52 g = 0.02 mol CrMol O= 1.27 g/ 16 g = 0.08 mol O

K= 0.02 mol K/ 0.02 mol Cr = 1; KCr= 0.02 mol Cr/ 0.02 mol Cr = 1; CrO= 0.08 mol O/ 0.02 mol Cr = 4; O4

KCrO4;Potassium chromate

Stoichiometry How many atoms are in 90 L of O2 gas at STP?

 What is the empirical formula of the compound that is 42.10 % carbon, 5.26 % hydrogen, 24.56 % nitrogen, and 28.07 % oxygen? If molecular mass of the compound is found to be 171.2 g/mol what is it's molecular formula? 

90 L O2

22.4 L O2

6.022 x 1023 atoms of O2

= 2.4 x 1024 atoms of O2

C2NOH3 = 57 g171.2 g / 57 g = 3(C2NOH3) x 3 = C6N3O3H6

1 mol O2

1 mol O2