!! 5.2.2, How bonding and structure are related to the properties of substances

Question 1

what occurs at melting point

what occurs at boiling point

Answer 1

melting and freezing

boiling and condensing

Question 2

what does the energy needed to change state from solid to liquid and from liquid to gas depend on

Answer 2

depends on the strength of the forces between the particles of the substance

the stronger the forces between the particles, the higher
the mp and bp of the substance

Question 3

what are the limitations of the simple solid, liquid and gas particle model

Answer 3

in the model there are no forces,

all particles are represented as spheres

and that the spheres are solid

Question 4

what is an aqueous solution

Answer 4

solution where the solvent is water

e.g salt water or rain

Question 5

what structures do ionic compounds have

describe their electrostatic forces

Answer 5

giant ionic lattices

very strong electrostatic forces of attraction between the positive and negatively charged ions

Question 6

what are the melting and boiling points of ionic compounds

and why

Answer 6

very high mp and bp

as the electrostatic forces require a great deal of heat and energy to break

as when heated, particles vibrate- so when they vibrate with enough energy the electrostatic forces break and the solid melts

takes very high temperatures as electrostatic forces so strong, hard to break

Question 7

1 example of an ionic compound

and it’s melting point

Answer 7

sodium chloride

800 degrees celsius

Question 8

when can ionic compounds conduct electricity

Answer 8

when they are melted or dissolved in water as they can now move and carry the charge

cannot when they’re solid as the ions cannot move

they’re locked in place by the strong electrostatic forces of attraction

Question 9

1. which substances tend to have relatively low mp and bps
2. and why
3. do they conduct electricity

Answer 9

1. usually liquids or gasses that consist of small molecules
2. these substances have only weak forces between the molecules

it is these intermolecular forces that are overcome, not the covalent bonds when the substance melts or boils

3. no because the molecules do not have an overall electric charge

Question 10

what makes intermolecular forces increase and decrease

Answer 10

the size of the molecule

bigger molecule = stronger intermollecular forces

Question 11

which type of forces hold ionic lattices together

Answer 11

electrostatic

Question 12

how can an element conduct electricity

Answer 12

it has delocalised electrons

Question 13

why is an alloy is harder than the pure metal

Answer 13

the atoms/ particles/ ions are different sizes

so there are no rows/ layers to slide

Question 14

what type of substance is an alloy

Answer 14

mixture