Chemistry 11 Unit 4 Flashcards Preview

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Flashcards in Chemistry 11 Unit 4 Deck (24):
1

Solubility Curves

-interpreting the solubility of certain substances at given temperatures per 100 g of H2O

-ensure that the amount dissolved is in 100g H2O. If not, make ratio
g/100g H2O

Sample Q:
-Find solubility of compound (given) at temperature (given) -->g/100g H2O

-Find temperature at solubility (given) and compound (given)-->using graph (tracing)

-Least/most soluble at temperature (given)--> L: lower on Y axis; M: higher on Y axis
(Higher the mass, more soluble)

-How much solute must be added to reach saturation point --> take saturation point at given temperature (on line) subtract amount already dissolved

2

Dissociation

-can be written as an equation
-when a salt (ionic compound; solid) dissolves in water to become ions (aqueous; + or -)
-subscript in original compound becomes the number of ions in the water

*not all compounds will dissociate (must check solubility)

3

Concentration of ionic species

Given concentration, use to find another concentration

-must use mole ratio (no need to convert to moles if volume of water remains constant)
-therefore can use mole ratio using concentrations instead of moles
-use of dissociation equations (write first)

4

Moles of ionic species

Given concentration, find moles

-must use mole ratio to find the concentration, which can be used in N = C*V to find the moles
-use of dissociation equations (write first)

5

Precipitation Reactions
Molecular Equation
Ionic Equation
Net ionic Equation

Molecular Equation:
regular Double Displacement reaction with reactants and products
-Must BALANCE
-include whether substances are aqueous (soluble) or solid (insoluble)

Ionic Equation:
-dissociation equation for each compound
-include coefficients from molecular equation
-include ion charges and aq
-Precipitate remains as s precipitate (no dissociation equation)

-cross out spectator ions, leaving only the ions in the net ionic equation

Net Ionic Equation:
-includes ions (coefficient, charge, aq/s) of reactants added to form --> precipitate (opposite of dissociation)

6

Solutions Stoichiometry

Similar to mass-mass stoichiometry

-need chemical equation with reactants and products
-convert to moles -->mole ratio -->convert to find

Formulas using:
C = n/v
n = m/mm
n = v/mv

*Keep volumes separate! (v for gases at STP, v solutions liquid in Litres)

Q's:
-mass -->find moles -->mole ratio-->convert to mass
-volume at STP -->find moles -->mole ratio--> volume (N = V/MV)
-concentration -->find moles -->mole ratio -->concentration

7

Diluting Solutions

Water is added to solutions to dilute (make less concentrated).

Formula: C1V1 = C2V2
Therefore n1=n2

C1= concentration of original or stock solution (mol/L)
V1= volume of original or stock solution (L)
C2= concentration of diluted solution (mol/L)
V2= total volume after dilution (L)

*every time concentrated solution becomes lower concentration -->dilution

Q's:
-final volume of solution after dilution
-original/stock volume
-final solution concentration
-volume of water added (V2-V1)

8

Mixing solutions

When two of the same solutions are mixed together, there is a new concentration.

Formula: New concentration
C1V1 + C2V2/V1 + V2

*Never have to rearrange

C1= concentration of first solution (mol/L)
V1= volume of first solution (L)
C2= concentration of second solution
V2= volume of second solution

Q's:
-new concentration after mixing (using formula)

9

How to Prepare a Solution with a specific concentration?

Given: volume (L), concentration, compound
1) choose a volumetric flask
2) Determine amount of solute needed
-calculate the number of moles (n = C*V)
-Then calculate molar mass of compound
-then determine the mass (m = n*mm)
3) weigh out the mass (g)
4) place the compound in a volumetric flask (choose volume: 1.00L)
5. Add a small volume (half of volume) of distilled water to dissolve the solute (swirl)
6. Fill the flask to the 1.00L (etc. depending on amount) line with distilled water -->use eyedropper at very end for accuracy

10

Concentration (Molarity)

Concentration is a measure of the amount of solute dissolved in a given quantity of solvent (Mol/L or M)

*Different from solubility-->maximum amount of solute that can be dissolved in a given quantity of solvent

Formula: C = n/V
n: the number of moles (might have to use n = m/mm first)
V= volume in Litres

Qs:
-using formula, rearranging formula to find n and v
-what mass is needed to make V and C -->find moles-->m = n*mm
-what volume is needed to dissolve mass with C -->convert to moles using mass-->v = n/C

11

Naming Acids

All bonded with H+

Simple Acids: no oxygen
-known as Binary Acids
-identify by seeing if do not have oxygen

Hydro + root of anion + ic + acid

Complex Acids: oxygen
-known as ternary acids
-identify by seeing if have oxygen

Root of anion + ic + acid

1 more oxygen: per-
1 less: -ous instead of -ic
2 less: hypo- -ous


Organic Acids:
-Contain COO- group
-Hydrogen placed at the end
Ex: CH3COOH is acetic acid

12

Naming Bases

-includes OH ion

Special: ammonia NH3

Ex: Sodium Hydroxide

-simply name like normal naming (+ -)

13

Definition of Acids

Svante Arrhenius defined an acid as any substance that produces an H+ ion as it dissolves in water.

Ex: HCl --> H+(aq) + Cl-(aq)

14

Definition of Bases

Svante Arrhenius defined a base as any substance that produces OH- ion as it dissolves in water (bases also called alkalis)

15

Properties of Acids

-Produce H+(as H3O+) ions in water (the hydronium ion is a hydrogen ion attached to a water molecule) Ions aqueous
-Taste sour/sharp
-feel harsh on the skin (maybe not immediately, but will)
-react with metals such as Mg and Zn to produce hydrogen gas (Corrode metals)
-react with carbonates (CO3 ion) and hydrogen carbonates (HCO3 ion) to form CO2 gas
-Electrolytes (solutions of acids conduct electricity)
-Litmus paper red colour
(blue paper to red
red paper stay same)
-Acids can be strong or weak (0-6.9)
-react with bases (containing hydroxide ions) to form a salt (ionic compound) and water in a neutralization reaction
-pH is less than 7


16

Properties of Bases

-Produce OH- (hydroxide) ions in water
-Ions aqueous
-Taste bitter, chalky
-Feel soapy, slippery
-Caustic (dissolve organic material)
-Litmus paper blue colour “Basic Blue”
(red paper to blue
blue paper stay same)
-Bases can be strong or weak
-Electrolytes (conduct electricity)
-React with acids (containing hydrogen ions) to form salts and water in a neutralization reaction
-pH greater than 7

-Compounds
-Solutions of bases conduct electricity

17

Root of anions:
(not with varied oxygen)
Cl
Br
I
S
P
F
ClO3
BrO3
IO3
SO4
PO4
NO3
CO3
CH3COO
C2H3O2
C6H5COO

Cl = chlor
Br = brom
I = iod
S = sulfur
P=phosphor
F=fluor
ClO3 = chlor
BrO3 = brom
IO3 = iod
SO4 =sulfur
PO4 =phosphor
NO3 =nitr
CO3 =carbon
CH3COO = ace
C2H3O2 = ace
C6H5COO = benzo

18

Monoprotic and polyprotic (diprotic and triprotic) examples

Refer to kinds of acids

Monoprotic: produce 1 hydrogen ion per molecule as they ionize Ex: HCl

Polyprotic: produce more than 1 hydrogen ion per molecule as they ionize

Diprotic: produce 2 hydrogen ions Ex: H2SO4

Triprotic: H3PO4

*choose anion with specific charges (ex: diprotic choose 2- and triprotic choose 3-)

19

Ionization

Also means dissociation

therefore ionization equations same as dissociation equations
-break down into H+ (aq) and - ions (aq) when dissolved in water

20

Indicators

Litmus Paper:
Blue -Base (Blue to red = acid, red to blue = base)
Red -Acid

Phenolphththalein: colourless indicator that turns pink in a BASE and remains colourless in acid and neutral

Bromothymol Blue:
-Base will be blue
-Acid will be yellow

Methyl Orange:
-Acid will be Orange
-Base will be yellow

21

pH Scale

Measures how acidic or basic a substance is
1-14

7= neutral
1-6.9= acidic
7.1-14= basic

Examples of strong acids (pH 0-3)-stomach acid
Ex: weak acids- lemon, vin eager (edible)
Ex: neutral - pure/distilled water
Ex: weak bases- baking soda
Ex: strong base-cleaners, bleach

22

Neutralization reactions

Between an acid and base to form water (l) and a salt (aq)

-balance reaction
-spectator ions
-molecular, ionic, net ionic equations

*all neutralization reactions have a net ionic equation with the EXACT same coefficient (know if balance right or not)

23

Neutralization calculations

-if say NEUTRALIZE, then need an equation (solve using stoichiometry)

24

Monohydroxic and polyhydroxic bases

produces number of OH- ions as it dissolves

Mono: ex: NaOH

Poly: ex: Mg(OH)2