Stoichiometry
Nomenclature
Acids/Bases
Molecular Structures
Solubility
100
This number describes the amount of entities in any mole.
What is its name and value?
Avogadros number, 6.02214*1023
100
Which one of the following is Chlorite?
ClO2 [ClO3]-
[ClO2]- [ClO4]-
[ClO2]- is Chlorite
ClO2 is Chlorine dioxide
[ClO3]- is Chlorate
[ClO4]- is Perchlorate
100
By the Lewis acid Theory, what is a lone pair acceptor defined as?
Lewis acids are lone pair acceptors.
Lewis bases are lone pair donators.
100
Draw all stable lewis resonance structures for [NO3]- and include formal charges
100
The solubility of argon in water:
a) is independent of pressure above solution
b) increases with increasing external partial pressure of argon
c) decreases with increasing external partial pressure of argon
d) gases are not soluble in water
b) increases with increasing external partial pressure of argon
Higher external pressures of gases increase the probability of gas molecules entering a solution, which increases gas solubility in liquids.
200
What is the balanced chemical equation of the reaction between Pb(NO3)2 and NaI?
Pb(NO3)2 + 2NaI -> PbI2 + 2NaNO3
200
Name the polyatomic ions and list their charge.
- HSO3 - CrO4 - HCO3
- S2O3 - NH4 - CN
[HSO3]- Bisulfite (Hydrogen Sulfite)
[CrO4]2- Chromate
[HCO3]- Bicarbonate (Hydrogen Carbonate)
[S2O3]2- Thiosulfate
[NH4]+ Ammonium
[CN]- Cyanide
200
List at least 3 strong acids and 3 strong bases.
HCl NaOH LiOH
HBr KOH
HI RbOH
H2SO4 CsOH
HNO3 Ca(OH)2
HClO4 Sr(OH)2
Ba(OH)2
200
Which row 2 element has 3 valence electrons and forms 3 electron domains when it bonds?
Boron
Boron is the only row 2 element that has 3 valence electrons. It forms 3 bonds with no lone pairs resulting in 3 electron domains.
200
Write the state of the following atoms when they are added to water. (g for gas, s for solid, l for liquids, and Aq for dissolved.)
- Na2(CO3) - ZnBr2
- HgO - Ni(OH)2
Na2(CO3)(aq), ZnBr2 (aq), HgO(s), Ni(OH)2 (s)
Alkali earth metals are always soluble
Halides are soluble except when bound to Ag+ or Pb2+
Most oxides are insoluble
Hydroxides are insoluble except when bound to NH4+, Ca2+, Sr2+, Ba2+
300
A solution of Sodium Carbonate is neutralized with 2 moles of Phosphoric acid. Assuming both reactants are fully used, how many moles of gas are produced?
3 Moles of CO2 are produced.
2H3PO4 + 3Na2CO3 → 3H2CO3 + 2Na3PO4
Carbonic acid (H2CO3) decomposes to form CO2 and water
3H2CO3 → 3H2O + 3CO2
300
What is the charge of Iron in Ferrous Citrate?
+2.
Ferrous is +2
Ferric is +3
300
Between HBr and HI, which is the stronger acid?
HI is stronger.
HI and HBr are both strong acids.
The conjugate base of HI and HBr are I- and Br- respectively.
I- is larger than Br- and has more area to spread a -1 charge. This makes I- more stable.
Since the conjugate base of HI is more stable than the conjugate base of HBr, HI is more acidic.
300
What is the approximate bond angle between the chlorine atoms in Sulfur Dichloride?
Bond angle is less than 109.5*
Using VSEPR, Sulfur in SCl2 forms a single bond to each chlorine, with 2 leftover lone pairs.
this means we have 4 electron domains -> electron geometry is tetrahedral (bond angle 109.5*)
2 Lone pairs = molecular geometry is bent
One or more electron domains are Lone pairs -> Bond angle between atoms is less than 109.5*.
300
A precipitate forms when Sulfuric acid is added to a solution containing Barium Nitrate and Sodium Nitrate. What compound is the resulting precipitate?
The precipitate is Barium Sulfate (Ba2SO4)
The reactions are:
2NaNO3(aq) + H2SO4(aq) -> 2HNO3(aq) + Na2SO4(aq) -> All products soluble: no rxn
Ba(NO3)2(aq) + H2SO4(aq) -> 2HNO3(aq) + BaSO4(s) -> Barium sulfate is insoluble, forms solid ppt.
400
An engine burns 4 moles of octane (C8H18) and 2 moles of heptane (C7H16). Assuming perfect combustion, how many moles of water are produced in total?
48 moles of water.
2C8H18 + 25O2 -> 16CO2 + 18H2O (4 mol octane = 36 mol water)
C7H16 + 11O2 -> 7CO2 + 8H2O (2 mol heptane = 16 mol water)
400
[BrO3]- is bromate. What is the formula for Hypobromous acid?
HBrO
Bromite = [BrO2]- Bromous acid = HBrO2
Hypobromite = [BrO]- Hypobromous acid = HBrO
400
Consider the reaction SiF4 + 2F− → [SiF6]2-
Is SiF4 a lewis acid, lewis base, or neither?
SiF4 is the lewis acid.
F- donates its lone pair to SiF4 and forms [SiF6]2-
(Lewis acid = LP acceptor, Lewis base = LP donator)
400
DAILY DOUBLE
What is the hybridization of Xenon in XeF4?
(Remember to consider lone pairs)
Xenon is sp3d2 hybridized
Xe in XeF4 forms 4 single bonds to each F atom, with 2 leftover lone pairs -> 6 electron domains
Each Xe-F bond needs a hybrid orbital -> One s (s) and Three p (p3) orbitals hybridise to form 4 sp3 orbitals (4 hybrid orbitals)
Each lone pair needs a hybrid orbital. But Xe-F bonds used all S and P orbitals.
Xenon has access to d orbitals -> Two d (d2) orbitals further hybridize with sp3 orbitals resulting in 6 sp3d2 orbitals
-> Xenon is sp3d2 hybridized
400
Seawater at 10*C can hold 8mg/l of oxygen gas. Will oxygen be more soluble if seawater temperature is raised to 20*C?
Oxygen will be less soluble in seawater at 20*C than at 10*C.
As temperature rises, gas molecules in liquid move faster. Faster movement results in more molecular collisions, and a higher chance of a gas molecule to escape the liquid leading to lowered solubility as temperature is increased.
500
In the reaction 2KNO3 + S + 3C → K2S + N2 + 3CO2, Which atom in KNO3 is reduced?
Nitrogen is reduced.
Oxidation state of atoms in KNO3
K is +1
N is +5
O is -2 (each)
Oxidation state of the same atoms in the products:
K in K2S is +1
O in CO2 is -2 (each)
N in N2 is 0 (Ground state)
Oxidation state of N changed from +5 -> 0 Therefore nitrogen was reduced.
500
What is the IUPAC name of Cr(CO)6?
Chromium hexacarbonyl.
Metal ion is Chromium, the ligand is carbonyl (CO) and there are 6 of them.
500
1 mole of HCl is added to a solution containing 1 mole of ammonium hydroxide. Assuming HCl and ammonium hydroxide completely react, Is the resulting solution acidic, basic, or neutral?
Resulting solution is Acidic.
The reaction is : HCl + NH4OH -> H2O + NH4Cl
NH4OH is a weak base -> Conjugate acid (NH4Cl) is a weak acid.
All HCl and NH4OH are used up (1:1 mol ratio) -> only NH4Cl remains in solution
Since NH4Cl is a weak acid, the resulting solution is acidic.
500
How many electrons participate in bonding in most metal carbonyl complexes? ( Eg: Fe(CO)5, Cr(CO)6 )
18 electrons participate.
Iron electron configuration is [Ar] 4s2 3d6 -> 8 Valence electrons. Carbonyl ligands contribute 2 electrons each. 8 + 2(5) = 18 electrons.
Chromium electron configuration is [Ar] 4s1 3d5 -> 6 Valence electrons. Carbonyl ligands contribute 2 electrons each. 6 + 2(6) = 18 electrons.
500
Mg(OH)2 has low solubility in water. Will adding HCl improve the solubility of Mg(OH)2 in water?
Yes, addition of acid will increase solubility of Mg(OH)2 in water.
Dissolution of Mg(OH)2 is an equilibrium:
Mg(OH)2(S) <-> Mg2+(aq) + 2OH-(aq)
Acid reacts with OH- and forms water, effectively removing OH- from solution.
From Le Chatliers principle, removing a product will push the equilibrium to consume reactants and favor products.
This will lead to more Mg(OH)2 dissolving in an acidic solution.