C1 Chemistry Top 35

Question 1

What is the difference between an element, compound and mixture?

Answer 1

Element - Made up of one type of atom that are chemically bonded.
Compound - Two or more different atoms that are chemically bonded.
Mixture - Two or more different atoms that aren’t chemically bonded.

Question 2

Give the formula for a) carbon dioxide b) carbon monoxide c) methane

Answer 2

a) CO^2 b)CO c)CH^4

Question 3

Balance the following equations:
a) Na + Cl 2 => NaCl
b) Na + H 2 O => NaOH + H 2
c) Al + FeO => Al 2 O 3 + Fe

Answer 3

a) 2Na + Cl 2 => 2 NaCl
b) 2Na + 2H 2 O => 2NaOH + H 2
c) 2Al +3 FeO => Al 2 O 3 + 3Fe

Question 4

Which method of separation is useful to separate an insoluble solid from a liquid?

Answer 4

Filtration

Question 5

Which method of separation is useful to separate a soluble solid from a liquid?

Answer 5

Evaporation or crystallisation

Question 6

Describe the process of distillation.

Answer 6

The action of purifying a liquid by a process of heating and cooling.

Question 7

Which method of distillation would you use to separate liquids with similar boiling points?

Answer 7

Fractional distillation

Question 8

In chromatography the baseline needs to be drawn in pencil, why?

Answer 8

So it wont run / dissolve in the solvent / split up

Question 9

Name the 3 subatomic particles in an atom and state their mass & charge.

Answer 9

Proton + Mass = 1 Neutron No charge Mass = 1 Electron 1/2000th

Question 10

Why is an atom neutral?

Answer 10

Equal number protons and electrons

Question 11

How many protons, neutrons and electrons are there in sodium (Na)?

Answer 11

11 Protons 11 Electrons 12 Neutrons

Question 12

What is an isotope and give an example with relation to abundancies.

Answer 12

Isotopes are different forms of the same element, which have the same number of protons, they may have different
numbers of neutrons.
They have the same atomic number, but different mass number. Eg C12 and C13

Question 13

Explain how Rutherford’s Scatter experiment disproved the Plum Pudding Model.

Answer 13

He projected a beam of alpha particles at a thin sheet of gold. He expected all of the particles to pass through. Most
particles did pass through, however a small number were deflected backwards. This led to the discovery or the
positively charged nucleus.

Question 14

Who discovered the existence of neutrons?

Answer 14

Chadwick

Question 15

Why did Newland call his periodic table the Law of Octaves?

Answer 15

He noticed similar elements every 8 th place
He called this the law of octaves as it was similar to musical scales

Question 16

Why didn’t people believe Newlands Law of Octaves?

Answer 16

Unfortunately the pattern only worked for the first 17 elements. Elements were placed in the same groups with
completely different properties!

Question 17

How did Mendeleev arrange the elements and why did people believe him instead?

Answer 17

Mendeleev lined up the elements in order of increasing atomic mass (similarly to Newland)
He started new lines to put similar elements in the same columns

He even left gaps when the pattern didn’t fit

Question 18

What is the key difference between Mendeleev’s periodic table and the modern periodic table?

Answer 18

1. Between 1894 and 1898 a whole new family was discovered by British scientists Lord Rayleigh and Sir William
   Ramsay; The Noble Gases
   These were not predicted by Mendeleev as they are very unreactive and therefore don’t have many noticeable
   properties!
2. In 1913 the electronic structure of the atom was discovered. Several different scientists working together realised
   that if the elements were put in order of increasing atomic number instead of mass, it all fits nicely!

Question 19

Describe what is meant by a
a) Period
b) Group

Answer 19

a) Period number of shells
b) Group number electrons outer shells

Question 20

Why are Lithium, Sodium and Potassium in the same group?

Answer 20

1 electron in outer shell

Question 21

State the common names for:
a) Group 1
b) Group 7
c) Group 0

Answer 21

a) Group 1 Alkali Metals
b) Group 7 Halogens
c) Group 0 Noble gases

Question 22

State 3 properties of the alkali metals.

Answer 22

low density
low melting and boiling points
very reactive

Question 23

Complete the following word equations showing the different reactions of the alkali metals:
a) Lithium + Water 
b) Potassium + Chlorine 
c) Sodium + Oxygen 

Answer 23

a) Lithium + Water  Lithium hydroxide and Hydrogen
b) Potassium + Chlorine  Potassium chloride
c) Sodium + Oxygen  Sodium oxide

Question 24

Universal indicator can be add to the water to determine whether the reaction between lithium and water was
successful. Why?

Answer 24

Changes to purple with alkali

Question 25

As you go down group 1, what happens to the: a) Reactivity b) Melting/Boiling Point

Answer 25

a) Reactivity increases b) Melting/Boiling Point decreases

Question 26

As you go down group 7, what happens to the: a) Reactivity b) Melting/Boiling Point

Answer 26

a) Reactivity decreases b) Melting/Boiling Point increases

Question 27

Group 7 are naturally coloured vapours, with the exception of Bromine. State the colour and state of the following: a) Fluorine b) Chlorine c) Bromine d) Iodine

Answer 27

a) Fluorine Yellow b) Chlorine green c) Bromine brown d) Iodine purple

Question 28

What is a displacement reaction?

Answer 28

If a reactive element comes into contact with the compound of a less reactive element a chemical reaction may take place. The less reactive element is removed from the compound and replaced by the more reactive element.

Question 29

Complete and balance the following symbol equation: Br 2 + NaI 

Answer 29

Br 2 + 2 NaI  2 NaBr + I 2

Question 30

Give 1 property of the noble gases and link this to their electronic structure.

Answer 30

Non-reactive due to full outer shell

Question 31

Explain why the boiling points of the noble gases increase as you move down the group.

Answer 31

Strong intermolecular forces

Question 32

Krypton is a gas at -153◦C, predict what state Argon is in at this temperature.

Answer 32

Gas

Question 33

State 3 properties/uses which are specific to the transition metals.

Answer 33

Hard and strong Good conductors of heat and electricity They have high melting points. They are not very reactive. They have a high density. They are useful as catalysts. Their ions are often 2+ but may be variable. Malleable Ductile Make coloured compounds

Question 34

Compare the difference between Group 1 and the transition metals for the following properties: a) Hardness b) Reactivity c) Melting Point

Answer 34

a) Hardness group 1 soft b) Reactivity group 1 more reactive c) Melting Point group 1 lower melting point

Question 35

Where can you find the following on the periodic table and what type of ion does each make: a) Metals b) Non-metals

Answer 35

a) Metals left side make + ions b) Non-metals right side - ions