AP Chem Unit 4 flashcards for self

There are 6 types of reactions

There are 6 types of reactions

Synthesis Reaction

Decomposition

Acid-Base Reaction:

Oxidation-Reduction

Hydrocarbon Combustion

Precipitation

EXPLAIN WHAT THEY ARE OR ELSE CHECK ONLINE

Solubility RULE

1. Compounds with alkali metal cation (Na+ Li+ K+, etc….) or an ammonium cation (NH4+) are always soluble

2. Compounds with a nitrate (NO3-) anion are always soluble

When ionic dissolved in water? What is the attraction?

The water particles surround the broken apart ions. Positive ions attract O in the h20, and negative ions attract H in the h20 ion dipole

Polyatomic ions

MEMORIZE them / add them in calculator

Balancing chemical equations

(Basic algebra)

You can use backsolving. Plug in choices to see which one works.

Other method try to balance out common elements such as H, O before other elements

Chemical calculations (stoichiometry / limiting reactant )

General steps for solving stoichiometry

1. Write out balanced chemical equation

2. Identify the known measurement

3. If known measurement is gram given convert to moles

4. Multiple by a mole ration using coefficient to convert to other elements

5. repeat steps a many times as you necessary

6. Cross out unit circle answer

   For limiting reactant

   1. Convert both to molar mass

   2. Convert to other reactant using mole ratio, see which one is greater or less than

   3. Then you know which is in excess

Percent error

% error = [experimental value - expected value] / expected value * 100 %

Gravimetric analysis

Way to use precipitation reactions in order to make quantitative determinations about the identity of an unknown sample.

Ex we can convert to moles of oh, and to mass

Then we divide by total mass in sample to find OH percentage

We compare this oh mass perecer to other common oh compounds.

The one with closest percentage is the identity of unknown

Oxidation state

In many chemical reactions electrons are transferred between the reactants. in order to determine which oxidation a states are gaining electrons and which are losing we check oxidation state:

1) any neutral atom that is not bonded to atoms of any other has oxidation state of zero Ex:o2

2) monoatomic ion has charge equal to that ion Ex: Na = Na+

3) in most compound oxygen is -2 except of h2o2

4)when bond to metal H is sometimes -1, ex CH4

5) in absence of oxygen the most electronegative will take oxidation = to common charge

6) MOST IMPORTANT COMBINED OXIDATION STATE MUST EQUAL TO IT’s OVERALL CHARGE ex : zero for neutral

Oxidation reduction

Oil Rig

Oxidation is loss of electrons (More charge)

Rig is gain of electrons (less charge)

Practice question to ensure understand

Redox titration

Helps determine unknown concentration (more in depth unit 8)

Acids and bases

Bronsted Lowry def:

Acid is substance capable of donating a H+ ion

Base is substance receiving an H+ ion. (Tend to form OH) Tend to be negative in charge

Conjugate pair

A strong acid’s opposite after donating H. SAME SPECIES WITHOUT H+ ion

Examples:

Nh4+ and NH3

H30+ and H20

H20 and OH-

Mix of these form buffer

Amphoteric

Ability for a substance that can act as either base or acid. WATER is amphoteric

Polypeptide acid

An acid that has two H+ ions and can be diluted 2 times and has 2 equilibrium points. Most polypeptides can act as indicator