GCSE Chemistry unit2

Question 1

what is a chemical bond

Answer 1

a compound contains two or more elements which are chemically combined

Question 2

what are the two ways to make a full outer shell

Answer 2

covalent bond & ionic bond

Question 3

what is an ionic bond

Answer 3

when non-metals react with metals, the metal atoms lose electrons to form a positive ion

Question 4

examples of ionic bonds

Answer 4

sodium chloride, magnesium chloride &

calcium chloride

Question 5

what’s a ionic bond

Answer 5

transferring bonding

Question 6

what’s a covalent bond

Answer 6

sharing electrons

Question 7

what are the properties of metal

Answer 7

the particles in the metal are in nice, neat rows, so that they can slide over each other. which means the metals can be bent or shaped

Question 8

why metals are good conductors of electricity and heat

Answer 8

Because the free electrons can move through the solid so that it will able to conduct electricity/heat

Question 9

what charge does the elements from group 1 have

Answer 9

1+

Question 10

covalent bond

Answer 10

a covalent bond is a strong bond between two non-metals atoms

Question 11

what is the metallic bond

Answer 11

the metallic bond is the attraction of these electrons to the positive ions

Question 12

properties of the metallic bonds

Answer 12

the bonds are strong

have a high melting and boiling point

Question 13

covalent bonds are _______, need _ ___ __ _____ to break the bonds

Answer 13

strong, a lot of energy

Question 14

balance the equation

_(Ca2+) + _(Cl-) —> ________

Answer 14

1(Ca2+) + 2(Cl-) —> CaCl

Question 15

What is hydration?

Answer 15

a reaction with water

Question 16

…….CuO + C —–> …………………… + CO2

Answer 16

2 CuO + C —>2 Cu + CO2

Question 17

Describe what happens to the copper ions during electrolysis.

Answer 17

copper ions are attracted to the negative electrode and there gains two electrons and formed copper atoms

Question 18

Why did most scientists in 1915 not accept Wegener’s idea of continental drift?

Answer 18

Wegener could not explain how continents could move

Question 19

Name the two types of hydrocarbon.

Answer 19

alkanes and alkenes

Question 20

Explain, in terms of particles and collisions, the effect that increasing the surface area of the marble chips has on the rate of reaction.

Answer 20

increases rate of the reaction because of more frequent successful collisions between particles

Question 21

Give one reason why using a catalyst reduces costs.

Answer 21

lower temperature can be used

Question 22

Describe how the structure of an alloy is different from the structure of a pure metal.

Answer 22

an alloy is a metal which has different types of atoms

and also alloy has distorted layers

Question 23

balance the equation

PbO + HNO3 —> Pb(NO3)2 + H2O

Answer 23

PbO + 2(HNO3) —>Pb(NO3)2 + H2O

Question 24

what is electrolysis

Answer 24

electrolysis is the process by which ionic substance are decomposed into simpler substance when an electric current is passed through them

Question 25

Give the total number of atoms in the formula Pb(NO3)2

Answer 25

9

Question 26

how to measure the rate of reaction

Answer 26

1:measure the rate at which a reactant is used up
2:

Question 27

what is the activation energy

Answer 27

the minimum energy needed for the particles to react

Question 28

Explain, in terms of particles, why liquid iodine does not conduct electricity

Answer 28

iodine has no localised electrons or ions so cannot carry charge

Question 29

Why do different compounds separate in a gas chromatography column?

Answer 29

different substances travel at different speeds

Question 30

Zn + H2SO4 ——->………………………… + …………………………

Answer 30

ZnSO4 and H2

Question 31

Why must the zinc chloride be molten for electrolysis?

Answer 31

so ions can move

Question 32

What is meant by an endothermic reaction?

Answer 32

takes in energy

Question 33

Give one reason why the calculated yield of magnesium might not be obtained.

Answer 33

some of the reactant may react in different ways from the expected reaction

Question 34

names some of the simple covalent molecules

Answer 34

hydrogen, ammonia, methane and water

Question 35

Explain why graphite can conduct electricity.

Answer 35

it have delocalised electrons so electrons can move through the graphite

Question 36

Suggest why carbon nano-tubes are used as lubricants.

Answer 36

nano-tubes can slide over each other because no bonds between the nano-tubes

Question 37

Give the formula of sodium oxide.

Answer 37

Na2O