chemical reactions- things to memorize

water is polar/nonpolar?

polar

what is the shape of water

bent or v-shaped

water is polar because the oxygen atom has a greater attraction for

electrons (higher electronegativity)

as ionic solids dissolve in water, the positive ends (hydrogen) attract anions, and the negative ends (oxygen) of the water are attracted to cations

hydration

the solubility of water depends on what two things?

• the attraction of the ions to each other within the solid

• the attraction of the ions to water molecules

which types of substances dissolve well in water, and which do not?

ionic and polar substances dissolve well in water, while nonpolar substances do not

a solution is a ____________________ made up of a solute and solvent. a solution is made up of two or more ________________________.

homogeneous mixture; pure substances

the solvent is the substance doing the dissolving. it is present in the _________________________.

greatest abundance

solution where H2O is the solvent

aqueous solution

a substance that dissociates into ions when dissolved in water

electrolyte

a _____________ may dissolve in water, but it does not dissociate into ions when it does so

nonelectrolyte

what type of compounds tend to be strong electrolytes

soluble ionic compounds, strong acids, strong bases

what type of compounds tend to be weak electrolytes

weak acids, weak bases

molecular (covalent) compounds tend to be _________________, except for acids and bases

nonelectrolytes

strong electrolytes:

strong acids, strong bases, soluble ionic salts

what are the strong bases?

group 1A metal hydroxides (LiOH, NaOH, KOH, RbOH, CsOH)
heavy group 2A metal hydroxides [Ca(OH)2, Sr(OH)2, Ba(OH)2]

what are the strong acids?

HCl

HBr

HI

HClO3

HClO4

HNO3

H2SO4

what items are always considered soluble?

NH4+, NO3-, alkali metals, acetate

Cl-, Br-, and I- are almost always soluble except when?

when they are paired with Ag⁺, Hg₂²⁺, and Pb²⁺

SO₄^2- (sulfate) is always soluble unless it is in a compound with:

Sr²⁺, Ba²⁺, Hg₂²⁺, or Pb²⁺

ammonia is a weak base/ weak acid; ammonium is a weak acid/ weak base

weak base; weak acid

S^2-, CO₃^2-, PO₄^3-, and OH^- are all insoluble unless paired with

alkali earth metals, NH4+, and for S^2- and OH^-, Ca²⁺, Sr²⁺, and Ba²⁺ as well.

carry current and they are strong acids/ bases and soluble salts

strong electrolytes

carry a small current, molecular substance

weak electrolytes

no current flows

nonelectrolytes

three classes of strong electrolytes

soluble salts (ex. NaCl, Pb(NO₃)₂); strong acids; strong bases (contain OH^-; ex. alkali metals with OH^- or Ca²⁺, Sr²⁺, and Ba²⁺

strong acids produce what when they are dissolved in water?

H+

all strong bases contain

OH^-

three classes of weak electrolytes

slightly soluble salts, weak acids, and weak bases

in single replacement, a _______ active element will replace a ________ active element within a compound

more; less

active metals can replace ________ in water

hydrogen

active metals can replace ________ in acid

hydrogen

active nonmetals can replace _____ active nonmetals

less

if all products are aqueous, then there is

no reaction

the three types of double replacement reactions

• formation of a gas

• formation of a precipitate

• acid/ base reactions

formation of a gas: H₂CO₃ →

H₂O + CO₂

formation of a gas: H₂SO₃ →

H₂O + SO₂

formation of a gas: NH₄OH →

H₂O + NH₃

formation of a gas: H₂S →

is a gas

ions bond together so strongly, the solvent can’t pull them apart

formation of a precipitate (double displacement)

formation of a molecular species

acid/ base reactions

redox reactions involve a transfer of

electrons

atoms in their elemental state have an ox number of

zero

for monatomic ions, their ______ is equal to their ox number

charge

F always has an oxidation number of

-1

oxygen has an ox number of ______, except when it is a _________

-2; peroxide

hydrogen usually has a ______ ox number, when it’s with nonmetals. it has a ________ ox number when it is with metals.

+1, -1

the sum of all oxidation numbers in the substance=

charge

if the substance is neutral, the ox number is

zero

the ox number of a polyatomic ion would be

the charge of the polyatomic ion

oil rig

oxidation is loss, reduction is gain

substance that causes oxidation- gets reduced

oxidizing agent

substance that causes reduction- get oxidized

reducing agent

acid/ base reactions always produce a

water + a salt

a method used to determine an unknown concentration of a solution by adding a second solution of a known [ ].

titration

[ ] means

the concentration of

neutralization reactions create

water. moles of H+ = moles of OH^-

an acid that can donate more than one hydrogen ion (proton) per molecule in an acid-base reaction

polyprotic acid

metals from Li to Na can (activity series of metals)

replace H from acids and water (very reactive)

metals from Mg to Pb can (activity series of metals)

can push H off acids only (fairly reactive)

highest metal on activity series of metals

lithium

lowest metal on activity series of metals

silver

chlorates and perchlorates (ClO₃^- , ClO₄^-) are always (in)soluble?

soluble