Topic 1- Key Concepts in chemistry

Question 1

What does aqueous mean?

Answer 1

Dissolved in water

Question 2

Learn some simple formulas of some simple compounds and ions- water, carbon dioxide, chlorine, ammonia, hydrogen, oxygen, ammonium, nitrate, sulphate, hydrogen, carbonate

Answer 2

answers on Card 5

Question 3

Name and explain some hazard symbols

Answer 3

Answer on CARD 6

Question 4

Describe the history of the atom

Answer 4

1. First was John Dalton who describes the atoms as solid spheres
2. Then was J.J Thompson who describes the plum pudding- where the negative electrons where floating in the positive charge
3. Then was the Rutherford gold experiment- where he fired positively charged alpha particles at a thin sheet of gold. And more particles deflected then expected-this suggests most of the atom is empty space.
4. Then was the refined Bohr model - which was supported by many experiments.

Question 5

Name the particle, relative mass and relative charge

Answer 5

answer on card 7

Question 6

Whats the radius of the atoms

Answer 6

-10
10 m.

Question 7

In an atom the number of protons equals to the number of…

Answer 7

electrons

Question 8

What is an ion

Answer 8

is an atom or a group of atoms that has lost or gained electrons

Question 9

Draw and evaluate a nuclear symbol:

Answer 9

on card 8

Question 10

What are isotopes

Answer 10

The have the same number of protons but a different number of neutrons . Same atomic number but a different mass number.

Question 11

What is the relative atomic mass of an element

Answer 11

Is the average mass of one atom ,of the element , compared to 1/12 of the mass of one atom of carbon 12.

Question 12

Calculative relative atomic mass- Boron has two isotopes, boron -10 boron -11 and their relative abundances are 4 and 16 respectively

Answer 12

(10X4) + (11X16)=216

216 divide 20 = 10.8

Question 13

What do groups represent in the periodic table ?

Answer 13

The number of electrons on the outer shell

Question 14

What do the periods represent in the periodic table ?

Answer 14

The number of electron shells

Question 15

What is a stable electronic structure?

Answer 15

full outer shell

Question 16

What are negative ions

Answer 16

They are anions that form when atoms gain electrons

Question 17

What are positive ions

Answer 17

They are cations that form when atoms lose electrons

Question 18

What does it mean when ions names end with -ate

Answer 18

Are negative ions containing oxygen and one other element

Question 19

What does it mean when ions name is ending in -ide

Answer 19

Are negative ions contain only one element

Question 20

What is ionic bonding?

Answer 20

When a metal and a non-metal react , metal losses electrons to form a positive ion and a non-metal gains electrons to form a negative ion (anion). The oppositely charged ions strongly attract each other through electrostatic forces of attraction.

Question 21

How can you show ionic bonding?

Answer 21

Through the dot and cross diagram

Question 22

Properties of ionic compound

Answer 22

1. ) High melting and boiling points because of the strong attraction between ions .Large amounts of energy needed to overcome the attraction
2. )Many dissolve easily in water , so they are able to carry an electric charge.
3. ) Solid ionic compounds don’t conduct electricity , because ions are fixed in place and can’t move

Question 23

What are the positives and negatives of using using 2D representations

Answer 23

+ shows how atoms are connected

-don’t show the shape and size of the substance

Question 24

What are the positives and negatives of dot and cross diagrams

Answer 24

+ used for showing how compounds are formed and where the electrons in the bonds come from
- does not show the size of the atoms and ions or how they are arranged

Question 25

What are the positives and negatives of 3D models

Answer 25

+ shows arrangement of the ions | - only shows the outer layer of the substance

Question 26

Properties of simple molecular structures

Answer 26

1. Substances containing covalent bonds usually have simple molecular structures 2. Forces of attraction between these molecules are very weak 3. To melt a simple molecular structures you have to break the feeble inter molecular forces not the covalent bonds 4. The bigger the molecules the stronger the intermolecular forces 5. Molecular compounds don't conduct electricity

Question 27

What are polymers?

Answer 27

Are molecules made up of long chains of covalently bonded carbon atoms.

Question 28

Properties of giant covalent structures .

Answer 28

1. They aren't soluble in water 2. They generally don't conduct electricity (apart from graphite and graphite. 3. They have very high melting and boiling points.

Question 29

Describe DIAMOND as a giant covalent structure

Answer 29

- is made up of a network of carbon atoms that each form four covalent bonds. - has a rigid lattice structure , making it hard , used to strengthen cutting tools - does not conduct electricity because there are no free electrons.

Question 30

Describe graphite as a giant covalent structure

Answer 30

- each carbon atom only forms three covalent bonds - there aren't any covalent covalent bonds between the layers- so its soft and slippery -ideal for lubricating - has a high melting point - has one decolonised electron , so it conducts electricity

Question 31

Describe graphene as a giant covalent structure

Answer 31

- is one layer of graphite - a sheet of carbon atoms joined together in hexagons - its one atom thick

Question 32

What is a buckmisterfullerene

Answer 32

it has a molecular formula C60 forms a hallow sphere

Question 33

What are nano-tubes

Answer 33

are also fullerenes, they are like tiny cylinders of graphene so they conduct electricity

Question 34

What is metalic bonding

Answer 34

attraction of the delocalized electrons for the positively charged metal ions

Question 35

Physical properties of metals

Answer 35

- has strong electrostatic forces of attraction - malleable - good conductors of heat and electricity

Question 36

Difference between metals and non-metals

Answer 36

1. they have different chemical properties 2. Non-metals generally don't conduct electricity 3. Non-metals gain electrons to form a full outer shell, metals lose electrons to gain full outer shell

Question 37

Why does the mass of gas seem to increase.

Answer 37

If the mass increases its because at least one of the reactants is gas that is found in air , before the reaction the gas is there its floating around in the air but its not contained in the reaction ,so you cant measure it

Question 38

Why does the mass of gas decrease

Answer 38

Because one of the products is a gas, so it can escape before measure

Question 39

What is a relative formula mass?

Answer 39

is the relative atomic masses off all the atoms in its formula added together

Question 40

What is the empirical formula?

Answer 40

tells you the smallest whole number ration of all atoms in the compound

Question 41

What is the Avogadro's constant?#

Answer 41

6.02X10 power23

Question 42

Equation that relates mass and moles

Answer 42

mass | moles X Mr

Question 43

Equation for concentration , mass and volume

Answer 43

mass | concentration(dm-3) volume (dm3)

Question 44

Practice calculating empirical formulas