Key Concepts In Chemistry

Question 1

What is a MASH equation?

Answer 1

Metal + acid —> salt + hydrogen

Question 2

What is a BASHO equation?

Answer 2

Base + acid —> salt + water

Question 3

What is a CASHOCO equation?

Answer 3

Carbonate + acid —> salt + water + carbon dioxide

Question 4

What are the symbols for these common acids?
Hydrochloric acid?
Chloride?
Sulphuric acid?
Sulphate?
Nitric acid?
Nitrate?
Hydroxide?
Carbonate?

Answer 4

HCl-
Cl-
H2SO4
(SO4)2-
HNO3
NO3-
OH-
(CO3)2-

Question 5

What are the symbols for these common molecules?
Water?
Ammonia?
Carbon dioxide?
Chlorine?
Hydrogen?
Oxygen?

Answer 5

H20
NH3
CO2
Cl2
H2
O2

Question 6

What is shown in ionic equations and what is taken out?

Answer 6

Only the reactive parts are shown

Any aqueous ions that are present on both sides are taken out

Question 7

How do you do ionic equations? (2)

Answer 7

Separate any aqueous ions that are present in a balanced equation

Cancel out the aqueous ions which are present on both sides

Question 8

Why do we use the Bohr model today?

Answer 8

Because it contains shells

Question 9

Each shell around an element has a f_____ e_____

Answer 9

fixed energy

Question 10

protons are h_____ and p________ c________

Answer 10

Heavily and positively charged

Question 11

Neutrons are h_____ and n_______

Answer 11

heavy and neutral

Question 12

Electrons have ______ ___ mass and a _________ charge

Answer 12

Hardly any mass and a negative charge

Question 13

Which one is the mass number?

Answer 13

the top one/the MASSive one

Question 14

Which one is the atomic number?

Answer 14

The bottom one

Question 15

How do you work out the number of neutrons?

Answer 15

Mass number - atomic number

Question 16

What is an element?

Answer 16

A chemical substance which cannot be broken down into any simpler substances by chemical reactions

Question 17

Are elements pure or impure?

Answer 17

Pure

Question 18

How many melting points do elements have?

Answer 18

1

Question 19

What is a compound?

Answer 19

Chemicals made from atoms of different elements joined by chemical bonds

Question 20

Are compounds pure or impure?

Answer 20

Pure

Question 21

How many melting points do compounds have?

Answer 21

1

Question 22

What is a mixture?

Answer 22

Made from different substances which are not chemically joined

Question 23

How many melting points do mixtures have?

Answer 23

A range

Question 24

Are mixtures pure or impure?

Answer 24

Impure

Question 25

What is the symbol for ammonium?

Answer 25

NH4+

Question 26

What is an isotope?

Answer 26

Atoms of the same element with the same number of protons but different numbers of neutrons

Question 27

What happens to an isotope's atomic and mass numbers?

Answer 27

Same atomic number but different mass numbers

Question 28

Calculate the relative atomic mass for: 30% thallium 203 70% thallium 205

Answer 28

(30x203)+(70x204)/100 = 204.4

Question 29

What does the group number on the periodic table represent?

Answer 29

Number of electrons on the outer shell

Question 30

What does a period on the periodic table represent?

Answer 30

Number of shells

Question 31

What did Mendeleev do? (3)

Answer 31

Arranged 50 known elements into a table Put elements into groups based on properties Put them in order of atomic mass

Question 32

What are ions?

Answer 32

Atoms which have lost or gained electrons

Question 33

Why do atoms gain or lose electrons?

Answer 33

To get a full outer shell

Question 34

What are anions?

Answer 34

Negative ions

Question 35

When are anions formed?

Answer 35

When atoms gain electrons, so they have more electrons that protons

Question 36

What is a cation?

Answer 36

A positive ion

Question 37

When do cations form?

Answer 37

When atoms lose electrons, they have more protons than electrons

Question 38

What is ionic bonding?

Answer 38

When a metal and non-metal react together

Question 39

In ionic bonding, what happens to the metal ions?

Answer 39

They lost electrons to become cations

Question 40

In ionic bonding, what happens the to non-metal ions?

Answer 40

They gain electrons and become anions

Question 41

What are ionic compounds?

Answer 41

Giant ionic Lattice structures

Question 42

What do ionic compounds form?

Answer 42

Crystalline solids

Question 43

Why do ionic compounds have high melting and boiling points?

Answer 43

Because strong ionic bonds are broken to melt or boil the substance

Question 44

When do ionic compounds conduct?

Answer 44

They only conduct when molten or dissolved

Question 45

Why can’t ionic compounds conduct as solids?

Answer 45

The ions can’t move

Question 46

Are ionic compounds soluble or insoluble?

Answer 46

Some are soluble, some are insoluble

Question 47

What do ions which are free to move carry?

Answer 47

An electric current

Question 48

What is covalent bonding?

Answer 48

When a non metal shares electrons with another non metal

Question 49

When do Giant covalent bonds form?

Answer 49

Between atoms in a giant lattice

Question 50

Why do giant covalent bonds have high melting and boiling points?

Answer 50

Because lots of strong covalent bonds are broken to melt/boil the substance

Question 51

Do giant covalent bonds conduct?

Answer 51

They never conduct EXCEPT graphite

Question 52

Are giant covalent bonds soluble or insoluble?

Answer 52

Insoluble

Question 53

When do simple covalent bonds form?

Answer 53

They form between atoms to form molecules

Question 54

What can simple covalent bonds form?

Answer 54

Solids, liquids or gases

Question 55

Why do simple covalent bonds have low melting and boiling points?

Answer 55

Because of weak intermolecular forces being broken

Question 56

Do simple covalent bonds conduct?

Answer 56

Never

Question 57

Are simple covalent bonds soluble or insoluble?

Answer 57

Some are soluble, some are insoluble

Question 58

What are polymers?

Answer 58

Molecules made up of long chains of covalently bonded carbon atoms

Question 59

When are polymers formed?

Answer 59

When lots of small molecules called monomers join together

Question 60

What does metallic bonding have which makes them conduct?

Answer 60

Delocalised electrons

Question 61

What is between the positive metal ions and the shared negative electrons in metallic bonding?

Answer 61

Strong forces of electrostatic attraction

Question 62

What state are metallic bonds at room temperature?

Answer 62

All solid except mercury

Question 63

Why do metallic bonds have high melting and boiling points?

Answer 63

They have a strong attraction which needs to be broken

Question 64

When do metallic bonds conduct?

Answer 64

When solid or liquid

Question 65

Are metallic bonds soluble or insoluble?

Answer 65

Insoluble

Question 66

What is the relationship between polymer chain length and melting point?

Answer 66

The longer the chain, the higher the melting point

Question 67

What are fullerenes?

Answer 67

Molecules of carbon shaped like closed tubes or hollow balls

Question 68

Why do fullerenes have a huge surface area?

Answer 68

Could help make great industrial catalysts