Chemistry

Question 1

What is the atomic mass equivalent to?

Answer 1

Protons + Neutrons

Question 2

What are the masses of protons, neutrons and electrons?

Answer 2

1, 1, no mass respectively

Question 3

What is an isotope?

Answer 3

When an element have a different amount of neutrons

Question 4

What is the relative atomic mass?

Answer 4

The average mass of all the isotopes

Question 5

What is the formula to calculate the amount of electrons that can fit in a shell?

Answer 5

2n²

Question 6

What happens after the 8 electrons are filled up in the THIRD shell?

Answer 6

It moves to the fourth shell as it takes less energy to fill up the first few spots in the fourth shell than it does to fill up the later shells in the third shell

Question 7

How are periods arranged in the periodic table?

Answer 7

Rows

Question 8

How are groups arranged in the periodic table?

Answer 8

Coloumns

Question 9

What’s special about elements that are in the same group?

Answer 9

They have similar properties

Question 10

Why is it that when an element has more shells, it’s more reactive?

Answer 10

As it’s further from the positive core, it is easier to get rid of the electrons

Question 11

Does it take less energy to fill up shells that are closer to the core or further?

Answer 11

Closer

Question 12

4 Characteristics of Metals

Answer 12

Lustrous appearance, ductile, malleable and able to conduct heat and electricity.

Question 13

Describe Alkali metals

Answer 13

They are group 1 metals with one valence electron and are highly reactive. They react violently with water forming a base and hydrogen gas. They are soft and the lower you go in the group, the more reactive they are.

Question 14

Describe Alkaline Metals

Answer 14

They are group 2 metals with 2 valence electrons and a 2 plus charge. They have low melting points and are soft. They are quite reactive but not as reactive as group 1 metals.

Question 15

Describe transition metals

Answer 15

They are in group 3-12 and form a large block in the periodic table. Gold an dcopper are the only ones without a silvery appearance. There is a transition between the charges. Some metals are magnetic and many form coloured compounds. Some have variable valencies (e.g. Fe(I) and Fe(II)

Question 16

Describe Metalloids

Answer 16

They are found in between metals and non-metals and share their properties. They can conduct or can semi-conduct electricity but nto as well as metals. There are 7 in total.

Question 17

Describe propterties of non-metals

Answer 17

They have common propteries and are in groups 14-18. They have a larger range of melting and bioling points and are mostly gases at room temperature. They don’t conduct electricity, can’t reflect light and have a dull appearance. They are also brittle.

Question 18

Describe Halogens

Answer 18

They have 7 valence elcetrons (-7 charge_ and react with metals to create salts and some are bleaches. Their MP and BP increase as you go down the group and the lower you go the less reactive they are

Question 19

Describe Noble Gases

Answer 19

They have 8 valence electrons so they have a charge of 0. They are very stbale and cannot form ions. All of them are gases at room temperature.

Question 20

What is the atomic radius?

Answer 20

It’s the measurement of the size of the atoms and decreases as you go across the periods and increases as you go down groups

Question 21

What are ionic bonds?

Answer 21

Ionic bonds are a cation and an anion held together by a strong electrostatic forces of attraction. They create a lattice structure. The ionic bond relationship is a give-and-take one.

Question 22

What are 5 common traits of ionic compounds

Answer 22

Brittle, solid at room temeprature, high MP and BP and their solutions normally conduct electricity and they normally dissolve in water to form aqueous solutions

Question 22

Why are ionic compounds brittle?

Answer 22

Because when force gets applied the particles rearrange and the like particles move together and then they repel each other, breaking the structure

Question 23

Why are ionic compounds solid at room temp?

Answer 23

Because of their strong electrostatic forces of attraction, it takes a lot of energy to break those bonds

Question 24

Why do ionic compounds have high MP and BP?

Answer 24

Because of their strong electrostatic forces of attraction, it takes a lot of energy to break those bonds

Question 25

Why do ionic compound's aquous solutions conduct electricity?

Answer 25

For conduction of electricity to occur there must be free moving electrons. But in a solid forms, they are in fixed positions. When liqud or molten, they have mobile charged particles allowing them to conduct electricity

Question 26

Why do ionic compounds normally form aqueous solutions?

Answer 26

Water is a polar solvent and cations and anions are more attracted to polar solvents. So the water just pull aparts the compound (dissolving it)

Question 27

What is covalent bonding?

Answer 27

Covalent bonding is how molecules achieve a full valence shell when reacting with each other. They have a sharing relationship where they share the electron between themselves.

Question 28

What is metallic bonding?

Answer 28

Metallic bonding is how metals form a valence shell when reacting with other metals.

Question 29

What is the law of conservation?

Answer 29

Total mass of reactants is equivalent to the total mass of products

Question 30

When do chemical reactions take place?

Answer 30

When bonds are broken between atoms and new ones are created

Question 31

What are the 6 different types of reactions?

Answer 31

Combination, decomposition, single displacement, redox, double displacement and combustion

Question 32

What is a combination reaction?

Answer 32

A combination reaction is when two reactants are combined to form one product (A+B → AB)

Question 33

What is a decomposition reactions?

Answer 33

When the reactant is broken down into two or more products (AB → A + B)

Question 34

What is a single displacement reaction?

Answer 34

When an element displaces another element which is less reactive than itself. Can also replace hydrogen if it is more reactive. (A + BC → AC + B)

Question 35

What is a redox reaction?

Answer 35

Shows the electron trasfer in a reaction. (OILRIG) Invovles the oxidation and reduction of electrons that occurs at the same time

Question 36

What is a double displacement reaction?

Answer 36

When two compounds exchange cations to form different compounds which are usually aqueous solutions. Can be a precipitate reaction or a neutralisation reaction. (AB + CD → AD + CB)

Question 37

What is a combustion reaction?

Answer 37

When the reactants react with hydrogen - hydrocarbons only contain carbon and hydrogen and always combust to form water and carbon dioxide

Question 38

What are some characteristics of acids?

Answer 38

They are corrisive and react with solid substances. Can be found in ant and bee stings and can also be found in fruits (citric acid) They have a sour taste and a low pH level

Question 39

What are some characteristics of bases?

Answer 39

Bases can be caustic and are often found in cleaning products. They are slippery or soapy to touch with a bitter taste

Question 40

What is the pH scale?

Answer 40

It is used to measure how basic or acidic a substance is. It can rage from 0-14. If the pH is less than 7, then it is acidic. The concetration of hydrogen is the measurement of a substance's acidicity. If a substance is more than 7, than it is basic. Bases are measured by their concentration of hydroxide. If the pH is 7 then it is a neutral substance

Question 41

What is a neutralisation reaction?

Answer 41

acids and base neutralise each other and create a salt and water

Question 42

What is a precipitation reaction?

Answer 42

When two solutions mix togther and an insoluble precipitate forms. Can only occur with double displacement reactions

Question 43

What are four factors that can affect the rate of reaction?

Answer 43

Concentration, temperature, surface area and catalysts

Question 44

How does the concentration of a substance increase the rate of reaction?

Answer 44

If the concetration of a substance is increased than the rate of reaction increases due to the increased frequency of successful collisions

Question 45

How does the temperature affect the rate of reaction?

Answer 45

The heat provides more kinetic energy to allow for more sucessful collisions to occur

Question 46

How does the surface area affect the rate of reaction?

Answer 46

An increased surface area, increases frequency of sucecssful collisions increasing the rate of reaction

Question 47

How do catalysts affect the rate of reaction?

Answer 47

Catalysts reduce the activation energy by providing an alernative for the reaction to complete. But catalysts are not used in the reaction and in the word equation they are on the arrow.