Principles of Chemistry

Question 1

What is the term for liquid to solid

Answer 1

Freezing

Question 2

What is the term for liquid to gas

Answer 2

Evaporation

Question 3

What is the term for gas to liquid

Answer 3

Condensation

Question 4

What is the term for solid to liquid

Answer 4

Melting

Question 5

What is the term for Gas to Solid

Answer 5

Deposition

Question 6

What is the term for Solid to Gas

Answer 6

Sublimation

Question 7

What is diffusion?

Answer 7

net movement of anything generally from a region of higher concentration to a region of lower concentration

Question 8

What is a solvent?

Answer 8

The liquid in which a solute dissolves

Question 9

What is a solute?

Answer 9

The substance which dissolves in a liquid to form a solution

Question 10

What is a solution?

Answer 10

The mixture formed when a solute is dissolved in a solvent

Question 11

What is a saturated solution?

Answer 11

A solution with the maximum concentration of solute dissolved in the solvent

Question 12

What does soluble mean?

Answer 12

Describes a substance that will dissolve

Question 13

What does insoluble mean?

Answer 13

Describes a substance that will not dissolve

Question 14

What is an element?

Answer 14

A substance made of atoms that all contain the same number of protons and cannot be split into anything simpler

Question 15

What is a compound?

Answer 15

A pure substance made up of two or more elements chemically combined

Question 16

What is a mixture?

Answer 16

A combination of two or more substances (elements and/or compounds) that are not chemically combined

Question 17

How can mixtures be separated?

Answer 17

By physical methods such as filtration or evaporation

Question 18

How does Distillation work?

Answer 18

Solution is heated, water evaporates into pure vapour, vapour goes through condenser, turns into pure liquid water.

Question 19

When is Distillation used

Answer 19

A solution of a liquid and soluble solid

Question 20

How does Fractional distillation work?

Answer 20

Solution heated to substance with lower boiling point, substance turns into vapour, goes through condenser, turns into pure liquid.

Question 21

When is Fractional Distillation used?

Answer 21

A solution of two or more liquids

Question 22

How does Filtration work?

Answer 22

Filter paper placed in filter funnel on a beaker, mixture is poured in filter funnel, filter paper will allow liquid particles to pass through, solid is left as residue

Question 23

When is Filtration used?

Answer 23

Solution on undissolved solid and liquid

Question 24

How does Crystallisation work?

Answer 24

Solution is heated, solvent evaporates leaving saturated solution, saturated solution is allowed to cool, crystals form, crystals are collected by filtration.

Question 25

When is Crystallisation used?

Answer 25

Dissolved solid and liquid

Question 26

In chromatography, what is the equation used to find the Rf

Answer 26

distance traveled by the compound divided by the distance traveled by the solvent front

Question 27

What is an atom?

Answer 27

The smallest particle of an element that contains electrons surrounding a nucleus that contains protons and neutrons

Question 28

What is a molecule?

Answer 28

A group of two or more atoms chemically combined to form an identifiable unit which retains the properties and composition of the substance

Question 29

What is the relative mass of a proton?

Answer 29

1

Question 30

What is the relative mass of a neutron?

Answer 30

1

Question 31

What is the relative mass of an electron?

Answer 31

1/1840

Question 32

What is the charge of a proton?

Answer 32

+1

Question 33

What is the charge of a neutron?

Answer 33

neutral

Question 34

What is the charge of an electron?

Answer 34

-1

Question 35

What is an isotope?

Answer 35

Atoms of the same element which have the same number of protons but a different number of neutrons

Question 36

What is the equation for Relative Atomic Mass (Ar)?

Answer 36

(% of Isotope A x mass of Isotope A) + (% of Isotope B x mass of Isotope B)/ 100

Question 37

Characteristics of Metals

Answer 37

Usually lustrous (shiny), Solid at room temperature (excluding mercury), Malleable, can be bent and shaped, High melting and boiling point

Question 38

Characteristics of Non-metals

Answer 38

Dull, non-reflective, Different states at room temperature, Flaky, brittle, Low melting and boiling points

Question 39

What is the value of Avogadro's constant?

Answer 39

6.02 x 10^23 per mole

Question 40

How to calculate mass given moles and Mr?

Answer 40

Moles x Mr

Question 41

What is the formula for percentage yield?

Answer 41

(actual yield/theoretical yield) x100

Answer 42

Write the element Write the value given for each element. This may be given as a mass, in g, or as a percentage Write the relative atomic mass of each element Calculate the moles of each element Moles = Mass/Ar Calculate the ratio of elements Divide all the moles by the smallest number of moles If you get a ratio that does not have whole numbers, you multiply by an appropriate number to make all the values into whole numbers

Question 43

How to calculate concentration?

Answer 43

Moles/volume in dm^3

Question 44

How to go from cm^3 to dm^3

Answer 44

divide by 1000

Question 45

How to calculate volume?

Answer 45

Moles x 24 (dm^3 mol^-1)

Question 46

What is a negative ion called?

Answer 46

Anion

Question 47

What is a positive ion called?

Answer 47

Cation

Question 48

What is the Ion for Hydroxide?

Answer 48

OH^-

Question 49

What is the Ion for Carbonate?

Answer 49

C03^2-

Question 50

What is the ion for Nitrate?

Answer 50

N03^-

Question 51

What is the Ion for Sulphate?

Answer 51

S04^2-

Question 52

When does ionic bonding occur

Answer 52

Between Metals and and Non-metals

Question 53

What diagram is used for Ionic Bonding?

Answer 53

Dot and Cross, two separate elements with brackets and charge

Question 54

What is the conductivity of ionic compounds

Answer 54

Poor in solid form, good in molten or in solution

Question 55

When is Covalent bond used

Answer 55

Between two-non-metals

Question 56

What diagram is used for Covalent Bonding?

Answer 56

Dot and Cross, Two elements interchanged with shared electrons in same loop

Question 57

What bonds do simple molecular structures have?

Answer 57

Covalent

Question 58

What are the characteristics of simple molecular structures?

Answer 58

Low melting and boiling points due to weak intermolecular forces of attraction, poor conductors of electricity,

Question 59

What are Giant Covalent structures?

Answer 59

Solids with high melting points

Question 60

Why do Covalent Structures have high melting points?

Answer 60

They have strong covalent bonds which require lots of energy to overcome

Question 61

Why can graphite conduct electricity?

Answer 61

Has layers, due to carbon atom only forming three bonds, one electron from each carbon is delocalised

Question 62

When is Metallic bonding used?

Answer 62

Between 2 metals

Question 63

Where do electrons move during electrolysis?

Answer 63

From anode to cathode

Question 64

Where do cations go during electrolysis

Answer 64

To the cathode because the cathode is negatively charged due to the electrons

Question 65

Where do the anions go during electrolysis

Answer 65

To the Anode because the anode is positively charged

Question 66

What happens at anode during electrolysis in aqueous solution?

Answer 66

If Halide ions present (I,Br,Cl) then halogen forms, if not, Oh^- goes to anode and forms oxygen

Question 67

What happens at cathode during electrolysis in aqueous solution?

Answer 67

if metal ions are less reactive then hydrogen, then metal is formed

Question 68

Half equation at Cathode

Answer 68

ion + electron(s) -> element Reduction (gain of electrons)

Question 69

Half equation at Anode

Answer 69

ion -> element + electron(s) Oxidation (loss of electrons)

Question 70

What do most covalent compounds act as?

Answer 70

Insulators