Study of Matter

Question 1

A homogeneous mixture: (2)

Answer 1

• Is uniform throughout i.e. the components cannot be distinguished.
• Is also called a solution.

Question 2

A heterogeneous mixture:

Answer 2

• Does not have the same composition, properties and appearance throughout i.e. the components can be distinguished.

Question 3

Solids can be separated from liquids by means of _____.

Answer 3

filtration

The solid is collected in filter paper, and the solution, called the filtrate, passes through the filter paper and is collected in a flask.

Question 4

What is distillation?

Answer 4

Distillation is a method used for purifying a volatile liquid product.

• The crude liquid reaction product is heated to a boil, the vapours rise and are condensed into a receiver.
• Nonvolatile impurities remain in the still pot.

Question 5

What is fractional distillation?

Answer 5

Homogeneous liquid mixtures can be separated by fractional distillation.
• Distillation requires the different liquids to have different boiling points.
• In essence, each component of the mixture is boiled and collected and the lowest boiling fraction is collected first.

Question 6

What is chromatography?

Answer 6

Chromatography is a technique used to separate substances on the basis of different abilities to adsorb to a surface and different solubility’s in a solvent.

Question 7

What is Gas-Liquid chromatography (GLC) ?

Answer 7

The greater the affinity the component has for the liquid layer (stationary phase) the slower it moves.

The greater affinity the component has for the gas (mobile phase) the faster it moves.

Question 8

What are physical properties?

Answer 8

Physical properties can be measured without changing composition of a substance.
Eg.
colour 
density 
melting point 
hardness...

Question 9

What are chemical properties? (2)

Answer 9

• Chemical properties describe how substances react or change to form different substances.
• Chemical properties also tell us about a substance’s composition.

– Water is 11% by mass H
– Sodium corrodes in air
– Potassium perchlorate explodes when shocked
– NH4NO3 decomposes when heated….

Question 10

What are intensive properties?

Answer 10

• Intensive properties do not depend on the amount of substance present.
e.g.
temperature
melting point….

Question 11

What are extensive properties?

Answer 11

• Extensive properties depend on the quantity of substance present.
e.g.
mass
volume….

Question 12

What is an amorphous solid?

Answer 12

• An amorphous solid is a solid in which there is no long-range order of the positions of the atoms.

Question 13

• Solids in which there is long-range atomic order are called _____.

Answer 13

crystalline

Question 14

(i) Cations formed from a metal have the same name as the metal.
Eg.

Answer 14

Li+ = lithium ion 
K+ = potassium ion 
Mg2+ = magnesium ion 
Ca2+ = calcium ion

• These are monoatomic ions i.e. ions formed from a single atom.

Question 15

(ii) If a metal can form cations of differing charges, the positive charge is given by a ____ numeral in parentheses following the name of the metal.
Eg.?

Answer 15

Examples:
Fe2+ = iron(II) ion Cu+ = copper(I) ion
Fe3+ = iron(III) ion Cu2+ = copper(II) ion.
• Most of the metals that have variable charges are transition metals.

Question 16

An alternative nomenclature method uses the endings ___ and ___ to represent the lower and higher charged ions, respectively.

Answer 16

-ous
-ic
Examples:
Fe2+ = ferrous ion Cu+ = cuprous ion
Fe3+ = ferric ion Cu2+ = cupric ion

Question 17

(iii) Cations formed from nonmetal atoms have names that end in ___.
Eg.?

Answer 17

-ium. 
 Examples: 
NH4+ = ammonium ion 
H3O+ = hydronium ion  
• These are polyatomic ions i.e. ions formed from 
more than one type of atom atom.

Question 18

(i) Monoatomic anions have names formed by dropping the ending of the name of the element and adding the ending ____.
Eg.?

Answer 18

-ide
Examples: 
Monoatomic   Polyatomic 
F- = fluoride ion OH- = hydroxide ion 
H- = hydride ion CN- = cyanide ion 
O2- = oxide ion  O22- = peroxide ion 
N3- = nitride ion

Question 19

(ii) Polyatomic anions containing oxygen have names that end in ___ or ___. The one with more oxygen is called ___.
Eg.?

Answer 19

-ate or -ite
-ate
Examples:
NO3- = nitrate ion SO42- = sulfate ion
NO2- = nitric ion SO32- = sulfite ion

• Polyatomic anions containing oxygen are called oxyanions.

Question 20

(iii) Prefixes are used when the series of oxyanions of an element extends to four members, as with
the halogens.
___ indicates one more “O” atom than the oxyanion ending in ___.
____ indicates one less “O” atom than the oxyanion ending in ___.

Answer 20

Per-
-ate
Hypo-
-ite

Example:
ClO4- = perchlorate ion (one more than chlorate)
ClO3- = chlorate ion
ClO2- = chlorite ion (one less O than chlorate)
ClO - = hypochlorite (one less O than chlorite)

Question 21

(iii) Anions derived by adding H+ to an oxyanion are named by adding as a prefix the word _____ or ______, as appropriate.
Eg.?

Answer 21

hydrogen 
dihydrogen
Examples:  
CO32- = carbonate ion 
HCO3- = hydrogen carbonate ion (bicarbonate ion) 

SO42- = sulfate ion 
HSO4- = hydrogen sulfate (bisulfate ion)

Question 22

• Names of ionic compounds are the ____ name followed by the anion name.
Eg.?

Answer 22

Examples:
BaBr2 Barium bromide

Al(NO3)3 Aluminium nitrate

Cu(ClO4)2 Copper(II) perchlorate Cupric perchlorate

Question 23

What is an acid?

Answer 23

An acid is defined as a substance whose molecules yield hydrogen ions (H+) when dissolved in water.

Question 24

i) Anions whose names end in -ide have an associated acid that have a ____ prefix and and ___ ending.

Answer 24

hydro-

-ic

Question 25

(i) Anions whose names end in -ate have an associated acid with an ___ ending.
(ii) Anions whose names end in -ite have acid with an ___ ending.

Answer 25

• ic

- ous

Question 26

Binary molecular compounds contain two different Elements. Procedure for naming:

Answer 26

(i) The name of the element farthest to the left in the periodic table is usually written first.
(ii) If both elements are in the same group in the periodic table, the lower one is named first.
(iii) The name of the second element is given an -ide ending.

Question 27

iv) Greek prefixes are used to indicate the number of atoms of each element. The prefix ____ is never used with the first element.
When the prefix ends in “a” or “o” and the name of the second element begins with a vowel e.g. oxide, the “a” or “o” is often dropped.

Answer 27

mono-