CHEM 2070 Final Exam Revision

What is solubility rule #1?

Most alkali metal salts and ammonium salts are soluble.

What is solubility rule #2?

Most nitrates (NO3-), acetates (CH3CO2-) and perchlorates ClO4-) are soluble.

What is solubility rule #3?

Most silver, lead, and mercury(I) salts are insoluble.

What is solubility rule #4?

Most chlorides, bromids and iodates are soluble.

What is solubility rule #5?

Most carbonates, chromates, sulfides, oxides, phosphates, and hydroxides are insoluble, except for hydroxides of Ba2+, Ca2+, and Sr2+ (three amigos) which are soluble.

What is solubility rule #6?

Most sulfares are soluble, except for calcium sulfate, barium sulfate, and strontium sulfate, which are insoluble.

What happens in precipitation/dissolution reactions?

Compounds either fall out of solution as solids or incorporate into solution as solutes.

What is the Etrans?

The kinetic energy of the molecule excluding the kinetic energy of spinning (rotation)

What are the 3 amigo elements/ions?

Calcium (Ca2+), Barium (Ba2+), and Strontium (Sr2+)

What reactions are most important/first to consider when classifying reactions?

Redox reactions because they are very energetic.

In a redox reaction, which species is favorably reduced and which is favorably oxidised?

The most electropositive species is favorably oxidised, and the most electronegative is favourably reduced.

The species with the most positive character (in polyatomic ions) is reduced, and the species with the most negative character is

What is necessary in order to classify a reaction as redox?

There must be a change in oxidation number within two species, and one of them must be oxidised and the other reduced.

What is the second reaction type to consider when classifying reactions?

Acid-Base reactions because they are also very energetic.

What is a strong acid? And what are the strong acids we encounter?

A strong acid is stronger than H3O+ - the strong acids we encounter are HCl (hydrochloric acid), HBr (hydrobromic acid), HI (hydroiodic acid), HNO3 (nitric acid), HClO3 (chloric acid), H2SO4 (sulfuric acid), HClO4 (perchloric acid), H3O+ (hydronium ion)

What is the principal cause for strong acids?

The inductive effect because of large changes in electronegativtiy.

In an acid cascade, where can you find the most acidic species and where can you find the most basic species?

The first acid is the strongest acid, and the last species of the cascade is the strongest base.

What defines a strong base? What are some examples?

A strong base is stronger or equal to OH- - Alkali metal and three amigo earth oxides (O2-) and hydroxides

What determines a favorable acid-base reaction (if it will occur)?

The stronger acid and base must be on the reactants side of the equation - the acid must be stronger than the conjugate acid, and the base stronger than the conjugate base.

What is the third reaction type to consider when classifying reactions?

Change of state reactions (precipitation/dissolution, because they are not very energetic)

What is the last reaction type to consider when classifying reactions?

Insertion and Elimination reactions because they are hard to understand in terms of energy.

What are the insertion reactions?

Na2O(s) + CO2(g) ---> Na2CO3(s)
SO3(g) + MgO(s) ---> MgSO4(s)

Under what conditions do insertion reactions occur?

Room temperature

What are the elimination reactions?

KClO3(s) ---> (high T) KCl(s) + O2(g)
CaSO3(s) ---> (high T) CaO(s) + SO2(g)
MgSO4(s) ---> (high T) MgO(s) + SO3(g)
CaCO3(s) ---> (high T) CaO(s) + CO2(g)
HgO(s) ---> (high T) Hg(g) + O2(g)

Under what conditions do elimination reactions occur?

High Temperature

What are oxo-acids?

Acids where a main group atom is bound to O atoms, which in turn may be bound to a hydrogen atom

How do you measure acid strength in oxo-acids?

The difference between the number of O atoms and hydrogen atoms is a measure of the acid strength - more O atoms compared to H atoms indicates a stronger acid.

What is group A of the metal activity series?

The most electropositive metals (Li, K, Ba, Ca, and Na) - these are alkali metals and the 3 amigos (Ba, Sr, Ca)

What reactions do group A undergo?

H2 evolving reactions occur in cold water, hot water, and acid

What is group B of the metal activity series?

All other common metals not in groups A, C, and D (e.g. Mg, Al, Mn, Cr, Ti)

What reactions do group B undergo?

H2 evolving reactions occur in hot water and acid

What is group C of the metal activity series?

Electronegative atoms (Co, Ni, Sn and Pb) - elements 3-4 steps away from Au (except Zn)

What reactions do group C undergo?

H2 evolving reactions only occur in acid.

What is group D of the metal activtiy series?

Most electronegative metals (e.g. Cu, Hg, Ag Au) - metals 1-2 steps away from Au.

What reactions do group D undergo?

Reactions do not occur to form H2.

What is the halogen reactivity series?

Halogen reactivtiy relates to electronegativity and therefore chances of being reduced - the more electronegative the halogen, the more likely it will react/displace another halogen - F is the most reactive halogen, it will displace any other halogen.