CHEMISTRY C1

Question 1

True or False? Metals are found on the right hand side of the stepped line in the periodic table?

Answer 1

False - Non-metals are found on the right and metals are found on the left of the stepped line.

Question 2

What are the 7 diatomic elements?

Answer 2

Iodine - I2
Bromine - Br2
Chlorine - Cl2
Fluorine - F2
Oxygen - O2
Nitrogen - N2
Hydrogen - H2

Question 3

What is a compound?

Answer 3

A substance that contains two or more
elements that are chemically combined.

Question 4

In compounds made up of non-metal elements only, the second word of the compounds name will always start with mon, di or tri. E.g. Carbon dioxide.

Answer 4

/

Question 5

What is an ion?

Answer 5

A charged particle formed when an atom, or a group of atoms, loses or gains electrons.

Question 6

What’s important with the number of ions when working out the formula of a compound?

Answer 6

The numbers of ions in a formula must give an equal number of positive and negative charges.

Question 7

What are reactants?

Answer 7

Substances that react together in a chemical reaction to form a product.

Question 8

What does the law of conservation of mass state about atoms in a chemical reaction?

Answer 8

No atoms are lost or made during a chemical reaction, so the total mass of the products is equal to the total mass of the reactants.

Question 9

What does a pure substance contain?

Answer 9

Consists only of one element or one compound.

Question 10

What is a mixture?

Answer 10

Consists of two or more different substances, not chemically joined together.

Question 11

What is filtration used for?

Answer 11

To separate an insoluble solid from a liquid.

Question 12

How does crystallisation work?

Answer 12

When the solution is warmed, some of
solvent evaporates leaving crystals behind.

Question 13

What is distillation used for?

Answer 13

To separate a solvent from a solution.

Question 14

How does distillation work?

Answer 14

The dissolved solute has a much higher boiling point than the solvent. When the solution is heated, solvent vapour leaves the solution. It moves away and is cooled and condensed.

Question 15

How does fractional distillation work?

Answer 15

• Vapours rise through a column which is hot at the bottom, and cooler at the top
• Vapours condense when they reach a part of the column that is below the temperature of their boiling point
• Each liquid is led away from the column

Question 15

What is fractional distillation used for?

Answer 15

To separate different liquids from a mixture of liquids. It’s useful for separating different fractions from crude oil.

Question 16

What is paper chromatography used for?

Answer 16

To separate mixtures of soluble substances.

Question 17

What are the two phases that chromatography relies on?

Answer 17

• The stationary phase, which in paper chromatography is very uniform, absorbent paper
• The mobile phase is the solvent that moves through the paper, carrying different substances with it

Question 18

What can a paper chromatogram be used for?

Answer 18

To identify substances by comparing them with known substances.

Question 19

Gon onto Physics p3 and learn about the early ideas of the atom

Answer 19

/

Question 20

How can relative atomic mass be written as a symbol?

Answer 20

Ar

Question 21

How do you calculate relative atomic mass?

Answer 21

Ar = Total mass of atoms/total number of atoms

(Mass x abundance) + (mass x abundance)/ 100

Question 22

Which scientist published the first periodic table in 1869?

Answer 22

Dmitri Mendeleev - A Russian chemist

Question 23

What is meant by an electronic structure?

Answer 23

The way in which electrons are arranged in an atom.

Question 24

What does the number of electrons in the outermost shell tell us about the element?

Answer 24

The group number that the element is in.

Question 25

What does the number of shells tell us about the element?

Answer 25

What period the element is in.

Question 26

What are some of the physical properties of metals and non-metals?

Answer 26

Metals (when solid): Non-metals (when solid): - Good conductor of - Poor conductor of heat heat and electricity and electricity - Shiny - Dull - High density - Low density - Malleable - Brittle - Ductile

Question 27

True or false? Metal elements gain electrons to form negative ions in a reaction.

Answer 27

False - Metal elements lose electrons to form positive ions and non-metal elements gain electrons in reactions to form negative ions.

Question 28

What are the elements in group 0 called?

Answer 28

The noble gases - they all have a full outer shell and are all non-metals

Question 29

What are some of the properties of noble gases?

Answer 29

- They all have low boiling points, higher further down the table - They are all unreactive and don't take part in chemical reactions -

Question 30

Why does the boiling point become higher further down the table?

Answer 30

- The atoms become larger as you go down - The intermolecular forces between atoms become stronger and more energy is needed to overcome these forces

Question 31

Why are noble gases so unreactive?

Answer 31

When elements react, their atoms complete their outer shells by losing, gaining, or sharing electrons. Atoms of group 0 elements already have stable arrangements of electrons. This means that they have no tendency to lose, gain, or share electrons.

Question 32

What are some of the properties of alkali metals (group 1)?

Answer 32

- They are soft - They have relatively low melting points - They have low densities The melting point decreases as you go down the group but the reactivity increases as you go down.

Question 33

What happens when the elements in group 1 take part in a reaction?

Answer 33

It's atoms each lose 1 electron.

Question 34

What happens when the alkali sodium hydroxide reacts with water? Hydroxide = OH

Answer 34

An alkaline solution is formed - The solution has PH greater than 7 - It turns the universal indicator solution blue or purple

Question 35

What are some observations when lithium, sodium and potassium react in water?

Answer 35

Lithium - Fizzes steadily; slowly becomes smaller until it disappears Sodium - Fizzes rapidly; melts to form a ball; quickly becomes smaller until it disappears Potassium - Burns violently with sparks and a lilac flame; quickly melts to form a ball; disappears rapidly, often with a small explosion

Question 36

What's the name given to the elements found in group 7?

Answer 36

The halogens

Question 37

What are some of the properties of the halogens?

Answer 37

- The further down the group you go, the higher its relative molecular mass - Further down the group the higher its melting point, molecules become larger and intermolecular forces are greater. - Less reactive the further down you go

Question 38

What is produced when halogens react with metals?

Answer 38

Salts

Question 39

What happens when these halogens react with hydrogen? - Fluorine - Chlorine - Bromine - Iodine

Answer 39

1. Explodes at room temperature and in the dark, forming hydrogen fluoride 2. Explodes with a flame or in sunlight, forming hydrogen chloride 3. Vigorous reaction when warmed with hydrogen, forming hydrogen bromide 4. Very slow reaction when heated strongly, forming some hydrogen iodide

Question 40

A more reactive halogen can displace a less reactive halogen from solutions of its salt. Give an example with sodium and potassium?

Answer 40

chlorine + potassium iodide → potassium chloride + iodine

Question 41

What are some of the properties of transition metals?

Answer 41

- they conduct electricity in the solid and liquid states - they are shiny when freshly cut - higher melting points - higher densities - greater strength - greater hardness

Question 42

Why did Mendeleev leave empty spaces on his periodic table?

Answer 42

For the elements that had not yet been discovered.

Question 43

How many elements are in the periodic table?

Answer 43

118