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1 mol = 6.0221 x 10 ; Speed of light: c = 3.0 x 10 m/s; 1Hz = s-1
C = K-273
K=C+273
-34
Planck's constant: h = 6.626 x 10
kg m2/s2 K mol
0)
J s ; 1 atmosphere = 760 torr R = 0.0821 L atm/ mol K = 8.314
Name all compounds you see here!
A) Density of a compound is 22 kg/cm3. Convert it to g/m3.
1.
……22 kg*( 1000 g/1kg) * (1/cm^3)*(100 cm/1m) ^3 = 22 1000 * (100)^3 g/m^3
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B) Density of a compound is 22g/m3. Convert it to kg/cm3
…………………………………………………………………………
C) Speed is 200km/h convert it to mm//s
………………………………………..
2. A) What is the number of protons in atom of nitrogen N?
From PT atomic number= number of protons = 7 N - 7…………………
B) What is the number of electrons in an ion of N?
We need to know the charge of the ion: if neutral atom number of protons is the same as
number of electrons, =7 , if …-3 add 3 more electrons (electron has negative charge) and so
on………………..
C) What is the number of neutrons in an isotope of N?
We cannot say unless we know mass number ( p + n) or are given number of
n…………………………………..
3. How many oxygen atoms are in 2g of Ba(ClO4)2
2g ( 1mol/ MM Ba(ClO4) 2 in g) *(6. 10^23 “molecules”/ 1mol) * (8 O atoms/1 molecule) =
MM Ba (Cl O4 ) 2 = Ba + 2 Cl + 8 O =137 + 2 *35.5 + 8 * 16)
= (2/MM)* (6 *10^23*8) =…
What else you know about the compound? Ba (ClO4) 2 is an ionic compound, Ba is element from 2
A group. It is soluble , also Ba (OH)2 is soluble. But Ba (SO4) is not soluble ( check solubility
table). The name of the compound is barium perchlorate ( no Roman numerals as it is type I metal
cation).
4.
How many moles of Sr(CN)2 are in 1.23 g of this chemical?
………………Find MM =MM Sr + 2 MM S + 2 N from pT
1.23g (1 mole/ MM) =…….
What else you know about the compound? The name is strontium cyanide ( group 2 A in PT, so type
I no roman numerals).
How many moles of Al( NO3)3 are in 2g of this compound?
…………………..
What else you know about the compound? Al 3+ is not 1A or 2A group member but is
exception like Zn 2+ and Ag+ in that they are type 1 metal cations and we do not use Roman
numerals in their names
5. The name of these ionic and binary compounds :
N 2 O4 is …………dinitrogen tetroxide…Note : binary (Greek prefixes) …..
N3F is………Note : binary , not ionic compound………..
Al(NO3)3 is…………aluminum nitrate…..
CuCl2 is………Note : Type II …………
CsI……………………..
Ca(ClO4)2
Fe2O3 is……Iron (III) oxide Note : Fe is type II metal cation , it requires Roman numeral in
the name
P4S10 is……tetraphosphorus decasulfide………………….
…Name all other compounds you see in this preexam/.study
quide……………………………………………………………….
6. Write down the formulae for: Note binary
a.
Carbon oxide………………CO.. Note: no first prefix if –mono (1)
b.
Carbon dioxide………………CO2…..
……………………………………………
c.
………………………….
7. Determine what mass in g of compound Z forms when y g of Y and x g of X react to produce Z
x X(g) + y Y (g)  z Z (g)
Use your masses and your reactions.
ExampleS : H2 + O2 (balanced
H2 + N2  balanced
If 13.6 g of methane (CH4) and 23.9 g of oxygen gas react completely in a combustion reaction, how
many grams of the PRODUCT CO2 you have?
Write balanced equation: CH4 + 2O2  CO2 + 2H2O
Convert mass to moles:
13.6 g * ( 1mol CH4/ 16g) = mol CH4
23.9g * (1mol O2 / 32) =mol O2
Convert moles of each reactant to moles of the same product CO2 using equivalents – stoichiometric
coeffitients conversion from that balanced equation
Mol CH4 * ( 1 mol CO2/ 1 mol CH4) = mol CO2 (from CH4)
Mol O2 * ( 1 mol CO2) / 2 mol O2 = mole CO2 (from O2)
Which one is smaller  That one is Limiting Reactant and determines how many moels of CO2 is
produced
Covert moles of CO2 from LR to mass of CO2
Moles CO2 (LR) * (( MM CO2 ) /1 mol CO2) = mass of CO2 produced
8.
Choose the correct net ionic equation for the metathesis reaction which occurs when
a) Ba(NO3)2…………….and ………KOH………(aq) are mixed.
b) Pb(NO3) 2 + KI (see textbook) ………………………………………….
c) BaCl2 + K2SO4 (see textbook)
d) Ba(OH)2 + 2 HI  Ba I2 + 2 H2O (l)
Net Ionic
2 OH- + 2 H+  2 H2O (l) (this is a typical acid base reaction where water is
NOT ionized – it is liquid so treated like (s) , changed state
!!!)………………………
e) Mg(NO3) 2 + 2 NaOH (see textbook)  Mg (OH)2 (solid, see
solubility table ) + 2 Na NO3 (all others are (aq))
Then IONIC equation by separating all soluble (aq) cations and anions:
Mg2+ + 2 NO3 - + 2 Na+ + 2OH-  Mg(OH)2 (s) + 2 Na+ + 2 OHOnly solid cannot be separated
Now NET IONIC equation by eliminating all spectator ions ( those on
both sides)
Mg2+ + 2 OH-
 Mg (OH)2 (s)
Note : Do the metathesis or exchange of ions first
a)
Ba(OH) 2 + KNO3 , then check what is soluble from the solubility table ( both are , no NET
IONIC reaction)
e) Carefully check solubility , Mg(OH)2 is NOT soluble although 2A
hydroxide
9. Which one of the following compounds is insoluble in water? (use solubility table,)
Ca(NO3)2, LiCH3COO, MgCl2, AgCl,
PbCl2, (same also with Br and I instead of Cl) , Na2SO4,
Pb(SO4) , Ba(SO4) , (NH4)2S, CuS, CaCO3, (NH4)3PO4, Ba(OH)2 , Mg (OH)2
10.
500 mL of a X(OH)2 solution was titrated to the equivalence point with 50 mL of a 1.93 M
solution of HCl. What was the concentration of the X(OH)2 solution?
…………………………………………….. (see textbook, neutralization, polyprotic –more than 1 H)
500 mL of a H2 SO4 solution was titrated to the equivalence point with 50 mL of a 1.93 M
solution of NaOH. What was the concentration of the H2 SO4solution?
You are asked to calculate the concentration of H2SO4 for which you were given only
Volume .. You know that M=mol/V, so moles of H2SO4 are needed.
In the titration process at the end you have complete reaction, so you have stoichiometric
equivalence of moles.
You know how many moles of NaOH you have: mol NaOH = M * V = 0.050 * 1.93
The reaction is
H2SO4 + 2NaOH 
So
mol H2SO4 = mol NaOH ( 1 mol H2SO4/ 2 mol NaOH)
M= mol H2SO4/0.5L
Note : try to find concentration of NaOH is M and V of H2SO4 is
given…………………………………………………………………
Try to find mol equivalents for Ba(OH) 2 and HBr reaction where acid is monoprotic , one H and
base is with two OH
11.
What is the molar concentration of Fe3+ in a solution made by diluting 500mL of 2.00 M
Fe2O3 to 1.00 L of solvent?
Dilution of Fe2 O3
:M Fe2O3= M V/ V = 0.5 *2/ 1
There are 2 moles of Fe3+ in each mole of Fe2O3 so MFe3+ = 2 * M Fe2O3
………………………………………
12. Which of the following are strong electrolytes?
HBr HCl HNO3 H3PO4 H2SO4 HF NaOH Ba(OH)2
CH3OH C2H5OH glucose HI HClO4 NH 3
KCl ………………………………………..
Note : check strong acids (including HI, HCl HBr etc. but not HF) and bases, soluble ionic
compounds for electrolytes, and molecular compounds
for non or weak electrolyte compound s
13.
What is the energy of a photon which has a frequency of 7.0 x 1015 Hz (cycles/sec)?
E = h * 7 10^15 =
Use data from the first page for h, Planck constant
……………………………………………..
What is the energy of a photon which has a wavelength of 500nm?..................
E= h c/ l (see data for h and c, speed of light in vacuum)
……………………………………………………………………………
14.
[ Ar]…4s2 3d10 4p1………..is the electron configuration of a(n) ____Ga atom. /ion
……………… has electron configuration:..[ ] ………………………..
Use this PT and Aufbau principle Pauli and Hunds rules . See textbook p 242 for example and
practice. Note ions of transition metals loose s electrons first
15.
Quantum rules n, l, m s
………………….
L= 0 s, l=1 p l=2 d.. l= 3 f
Example : What are possible m numbers for each of the following :
8 f  n=8 f means l=3, so m = -3,-2, -1, 0, 1, 2, 3
6 s  n=6 l=0
m=0
5 d…………………………………
4 p …………………………………..
16. Of the following elements, which has the largest first ionization energy?
O, N, P, Si, Na, K ….(Use PT , see textbook for trends,
increases left-right, bottom -up)
17. Of the following elements, which has the largest radius?
……………………………….(Use PT, trends) (increases top-down, right-left)
18. The Lewis structure , octet (y/n),formal charges, number of electron domains, molecular electron
domains geometry (names), hybridization, lone pairs, bondings (single,..), angles , molecular
geometry (names of geometries) , polarity , hydrogen bond , number of resonances (if exist)
For the following molecules: CsBr, ZnS, HI, Ba(OH)2, Na2CO3, H2CO3, CO3 2-, Na2SO4,
SO2-, NO3-, HNO3, …SF6, NH3 , PH3 AsH3, As F3, IF3, XeF4, H2O, H2S, NCl3, CH4,
CH3Cl, CF4, , BCl3, BF3,BeCl2, BeF2, Cl2, F2, O2, O3, CO2, SO3, XeO2, H3PO4, CO2,
NO2-, PCl5,SF4, ClF3, XeF2,SF6, BrF5, XeF4……………………………………..
Example comparisons:
For each of the following molecules: BeF2 OCl2 BF3 NF3 ICl3
Lewis structure
octet (y/n)
formal charges
number of electron domains
molecular electron domains
geometry (figure, names)
hybridization (sp, sp2, etc…)
lone pairs (how many)
bonds (single, double,..)
angles
molecular geometry (names of geometries)
polarity (polar or nonpolar)
hydrogen bond (yes, no)
number of resonances (if exist)
CCl4 SCl4
XeCl4
SCl6
Example comparisons:
For each of the following molecules: NO3-
O3
CO3 -
C6H6
SO4
2-
Lewis structure
octet (y/n)
formal charges
number of electron domains
molecular electron domains
geometry (figure, names)
hybridization (sp, sp2, etc…)
lone pairs (how many)
bonds (single, double,..)
angles
molecular geometry (names of geometries)
polarity (polar or nonpolar)
hydrogen bond (yes, no)
number of resonances (if exist)
19.
Calculate the number of moles of an ideal gas if it has a pressure of p atm, a volume of V L,
and a temperature of T oC.
PV=nRT
n= p V/ R T
1atm = 760 torr, T= 273 + C
20.
Calculate pressure of an ideal gas if it has n moles , a volume of V L, and a temperature of T
oC.
P= n R T /V
21.
Calculate Volume of an ideal gas if it has n moles , a pressure of p atm (or torr), and a
temperature of T oC.
V= p /
nRT
Etc………………………………………………………………………..
22. What uis the MM of a molecule density d, at T K, p atm in vol V?? (try simple molecules)
MM== d R T /p………………………………….
23. Which of the following molecules would have the lowest rms velocity at T K, p atm in vol V??
…v = ( 3 R T /MM) ^1/2……
23a )Calculate molar fraction if pressure if a gass is Pa and total pressure is P tot
\
X = pA/Ptotal
24. What types of intermolecular forces exist between molecules like X
general list before
a.
b.
c.
d.
and Y ? (use molecules from
Dispersion , and ion-dipole
dispersion forces, hydrogen bonding,
dispersion forces, dipole-dipole,
dispersion forces only
Example : Find the dominant force type write do not mix
CH3 OH CH3OH
hydrogen
CH3OH
HF hydrogen bond
H2O
HI polar
C6H6 CF4
dispersion
NaCl NH3
ion-dipole
C10H22 H2O do not mix
25.
Shown below is a phase diagram for A system . Use this phase diagram to pick the correct
statement from the following multiple choices.
Figure (see textbook phase diagrams p )
Identify all important points ( gas/liquid, liquid solid limits, normal points boiling and melting,
critical ppoint…..
Identify state of the system at different P and T
26. Which one of the following substances would be the most soluble in X?
Say in C6 H6
27. Which one of the following substances would NOT be soluble in X?
In H2O……………………………………………………….