Week 4 - Chemical Sciences Part 1

Question 1

What is matter?

Answer 1

Takes up space and has mass

Question 2

What are the four elements

Answer 2

Earth

Fire

Air

Water

It was once believed that everything consisted of these 4 elements but now is classified by atomic properties seen on periodic table of elements

Question 3

Atomic number

Answer 3

Atomic number goes up - number of protons

Atomic weight not shown - approximately double

Question 4

What it as atom

Answer 4

Generic term which focuses on structure

Question 5

What is an element

Answer 5

Properties and name

Question 6

What is a compound

Answer 6

Different elements joined together

Question 7

Atom has three particles- what are they and where are they situated

Answer 7

Protons - positively charged

Nutron - no charge

Electron - negativity charged

They are located in the nucleus of the atom

Question 8

What happens to electrons?

Answer 8

Cannot change the nucleus of an atom so we focus on the electrons (spin around the outside)

Electrons spin in rings (Shells) and there are specific numbers in each shell

First - 2

Second - 8

Third - 8

The outer shell can beg, borrow, steal or give up electrons - these are called valence electrons

Question 9

What is a compound?

Answer 9

A compound is a molecule that contains at least two different elements - all compounds are molecules but not all molecules are compounds.

Question 10

What is a molecule?

Answer 10

Formed when two of more atoms join together chemically

Question 11

Why do molecules/compounds stay together?

Answer 11

Valence electron is outer most electron shell associated with the atom and the different types of bonds between the electrons

Question 12

Octet rule

Answer 12

Atoms lose or gain electrons until they are surrounded by 8 valence electrons

Question 13

What is a covalent bond?

Answer 13

Bond formed between two or more atoms by a sharing of electrons (they can be polar or non polar)

Question 14

Iconic bond?

Answer 14

Bond formed on the basis of electrostatic forces that exist between oppositely charged ions - ions are atoms by transfer of one or more electrons

When an atom loses an electron, it loses a negative charge and becomes a positive ion
When an Atom gains an electron, it gains a negative charge and becomes a negative ion

Question 15

Metallic bond

Answer 15

Bonding in which the bonding electrons are relatively free to move throughout the 3D structure

Question 16

Chemical bond

Answer 16

Force of attraction which holds two or more atoms together

That force of attraction is between one or more valence electron (negativity charged) held by one of the atoms at the positively charged nucleus of the second atom

Question 17

What are polar and non polar covalent bonds

Answer 17

Polar - unequal sharing
Type of chemical bond where a pair of electrons are unequally shares between two atoms
Not shared because one atoms spends more time with the electron than the other atom
One has a stronger pull

Non polar - equally sharing
Two atoms share a pair of electrons with each other
Glue two atoms together to form a molecule
Requires a lot of energy to break this

Question 18

Mass of atom?

Answer 18

Atoms mass comes from the weight of its nucleus

Atomic number refers to the amount of protons it has

Atomic mass = how many protons and how many electrons

Question 19

What is volume?

Answer 19

The amount of space an object occupies

Measurement of space inside a 3D object

Question 20

How is mass different from weight?

Answer 20

Mass is how much stuff is in an object

Weight is determined by gravity - how much pull to the earth

Question 21

What is density?

Answer 21

Measure of how tightly packed matter is in the substance

Bigger nucleus, higher atomic number - more dense and a higher atomic weight

Question 22

Alternative conceptions about matter?

Answer 22

Students think that something is large in size - heavier in weight

Question 23

What is particle theory?

Answer 23

Matter is made of particles including atoms, molecules and compounds

Each substance has unique particles that are different from other substances

Particles of matter are held together by very strong forces

Temperature effects speed of particles - higher is faster, cool is softer

Question 24

What are states of matter?

Answer 24

Solid, liquid and gasses

Question 25

CDSU for Solids

Answer 25

Atoms/molecules move but in the same position relative to one another

They will vibrate and stay in the position they are in

Question 26

Liquid CDSU

Answer 26

Molecules move around each other and change position relative to one another while staying in contact

They are always touching

Question 27

Gas CDSU

Answer 27

Molecules spend most of their time alone

Zip through an empty space and hit one another

May only meet once and never again

Gas can expand more than solids and liquids because it is an empty space

Question 28

Gas microscopic level

Answer 28

Assumes shape and volume of its container

Compressible - lots of free space between each molecule/compound

Flows easily - can move past each other

In this phase there are weak molecular forces

Question 29

Liquid microscopic level

Answer 29

Assumes the shape of container it occupies

Can slide past each other

Not easily compressible - little free space

Flows easily

Molecular forces are weaker than in a solid

Question 30

Solid microscopic level

Answer 30

Retains a fixed volume and shape - locked into place

Not easily compressible - little free space

Does not flow - cannot slide past each other

Molecules are closely bound by molecular forces

Question 31

What does changing states require?

Answer 31

Requires energy - mainly in the form of heat

Question 32

Is water vapour smoke?

Answer 32

No - this is an AC

Ask students what it looks and smells like