pure substances and mixtures what is the difference between a pure substance and a mixture? what are...
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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
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