Module 1 - Properties and Structure of Matter

Question 1

Distinguish between Homogenous and Heterogenous mixtures.

Answer 1

Homogenous: Pure substances that is uniformly mixed and is only in 1 phase. (Solid, gas, liquid).

Heterogenous: Not uniformly mixed substances that are impure. Has more than 1 phase contained (Sand, rocks).

Question 2

Define melting point.

Answer 2

Lowest temperature at which a solid changes to a liquid.

Question 3

Define Freezing Point.

Answer 3

Highest temperature at which a liquid turns into a solid.

Question 4

Define Boiling Point.

Answer 4

Lowest temperature at which a liquid boils into gas.

Question 5

State the formula for density.

Answer 5

Density = mass ÷ volume

Question 6

Explain the process of Filtration.

State the physical property used.

Answer 6

A method of separating an undissolved solid from a liquid or aqueous solution, through a filter funnel.

PP - Particle size of solid being filtered.

Question 7

Explain the process of Distillation.

State the physical process used.

Answer 7

Process of boiling a solution into gas, then is condensed back into a liquid and separated from the initial solution.

PP - Big difference in boiling points.

Question 8

Explain the process of Fractional Distillation.

State the physical process used.

Answer 8

Process of boiling a solution through many successive distillations. Has a fractioning column.

PP - Small difference in boiling points.

Question 9

Explain the process of Sedimentation / Decantation.

State the physical process used.

Answer 9

Process where solids settle to the bottom of the container, and liquid is slowly poured out.

PP - Density of solid.

Question 10

State the formula for percentage composition of an element/component, regarding mass.

Answer 10

% Composition = (Mass of component ÷ Total mass of mixture) x 100

Question 11

List the 4 characteristics of Metals.

Answer 11

1) Solids at room Temperature
2) Shiny/lustrous appearance.
3) Good conductors of heat and electricity.
4) Malleable and ductile.

Question 12

Define what Isotopes are.

Hence, explain what ‘relative abundance’ is.

Answer 12

Element atoms that have a different number of neutrons in their nuclei than protons.

Relative Abundance: % of the isotope in the naturally occurring element.

Question 13

What are the 3 types of radiation that Radioisotopes give off?

(State an example of each). H_ , ___on, __ght & _-__ys

Answer 13

1) Alpha (α) rays -(Helium ion) Loses 4 atomic mass and 2 protons
2) Beta (β) rays - (electrons) Neutron converts into a proton.
3) Gamma (γ) rays - (Light and X-Rays) No change to Atomic mass or protons.

Question 14

Define the ‘half-life’ of a radioisotope.

What is emitted and what quantity changes?

Answer 14

Half-life: Time required for half the atoms in a given sample to undergo radioactive decay.

Emits α, β or γ rays and mass of sample halves.

Question 15

Distinguish between ionic compounds and covalent compounds.

Answer 15

Ionic compounds consists of non-metal and metals bonding with one another through transferring electrons.

Covalent compounds are non-metals bonded together, by sharing its electrons.

Question 16

List the electron sub-shell orbitals. (1s2, 2s2, …)

Answer 16

1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6, 5s2, 4d10, 5p6, 4f14…

Question 17

List the maximum number of electrons for the 4 electron shells.

Also, list the number of electrons per sub-shell. (s, p, d, f)

Answer 17

1st Shell: 2 | 2nd Shell: 8
3rd Shell: 18 | 4th Shell: 32

s: 2 | p: 6 | d: 10 | f: 14

Question 18

State the colours associated with each metal
1. Lithium (Lic) | 2. Sodium (Nay) | 3. Potassium (Kill) | 4. Calcium (Car) | 5. Barium (Bag) | 6. Copper (Cub) | 7. Strontium (Shred)

Answer 18

Li (lithium) + C(rimson) = Lic
Na (sodium) + Y(ellow) = Nay
K (potassium) + L(ilac) = Kill
Ca (calcium) + R(ed) = Car
Ba (barium) + G(reen) = Bag
Cu (copper) + B(lue) = Cub
Sr (strontium) + R(ed) = ShreddeR

Question 19

Explain why an element gives off different emission spectrums. (Different colours on emission spectrum)

Answer 19

Each periodic element contains different wavelengths due to the total electrons and valence electrons they each have.
The no. of energy levels and radius from valence shell to nucleus also differs between elements.

Question 20

Explain the process of atoms gaining energy, and how it is released by electrons.

Answer 20

As an atom gains energy, the electrons enter an ‘exited state’ where it must give off UV, visible and infrared radiation energy, to go back to its normal states.

Question 21

List the steps to calculate the relative atomic mass of an isotope.

Answer 21

1) Identify the number of isotopes used and their atomic mass.
2) Use the percentage composition as a number (% given) x Isotope number (no. of neutrons).
3) Add all the calculated values and divide by 100.

Question 22

Define what First Ionisation Energy is.

State its periodic trend.

Answer 22

The energy required to remove an electron from the atom of an element.
Diagonally increases from left to right.

Question 23

Define what Allotropes are.

Answer 23

Allotropes are different physical forms of it’s initial element as it consists of different molecular structures.

Question 24

Explain the two different allotropes of Carbon and their structure.

1) Diamond
2) Graphite

Answer 24

1) Diamond: A 3D covalent network lattice. Each carbon is bonded to 4 other carbon atoms in a tetrahedral arrangement.
2) Graphite: Layered carbon structure bonded in flat hexagonal rings. Each carbon is bonded to 3 other carbon atoms, forming 2D bonds.

Question 25

Explain what Dispersion forces are.

How is this force strengthened?

Answer 25

Temporary electrostatic forces between covalently-bonded electrons which pair-up, to create ‘temporary dipole moments’.

Forces are strengthened when no. of electrons increase due to atom/molecule size increasing.

Question 26

Explain what Dipole-Dipole forces are.

Which two molecules can it only be formed between?

Answer 26

Forces of attraction between oppositely charged ends of polar molecules, with negative side being attracted to the positive side.

Only formed between 2 polar molecules, not 1 polar, 1 non-polar.

Question 27

Explain what Hydrogen Bonds are.

What is the condition for this bond to be formed?

Answer 27

Strongest covalent bonds formed between Hydrogen atoms and either Nitrogen, Oxygen, or Fluorine atoms. Each connection must be in polar attraction.

Condition: Each atom connected, must also be connected with other H, N, O or F atoms.