bonding, structure, and properties

Question 1

Thermochromic

Answer 1

define - change colour at diff temps

use - thermometer strips

Question 2

photochromic

Answer 2

define - change colour at diff light intensities

use - sunglasses

Question 3

polymer gels

Answer 3

define - can absorb a large volume of liquid

use - nappies

Question 4

shape memory alloys

Answer 4

define - if deformed, returns to og shape when heated

use - spectacle frames

Question 5

shape memory polymer

Answer 5

define - if deformed, return to og shape when heated

use - car bumpers

Question 6

define alloy

Answer 6

solid mixture of different metals

Question 7

define smart materials

Answer 7

materials whose properties change in response to their environment

Question 8

name 2 nanomaterials

Answer 8

nano titanium dioxide and nano silver

Question 9

define nanomaterials

Answer 9

materials with particle diameters of less than around 100 nanometers. have different properties compared to ‘bulk’ materials. risks of humans exposure not fully known.

Question 10

nano titanium dioxide

Answer 10

property - absorbs ultra-violet light

use - sunscreen

Question 11

nano silver

Answer 11

properties - antibacterial

use - antibac creams and coatings

Question 12

metallic bonding strength

Answer 12

the larger the ion charge, the stronger the metallic bond.

Question 13

graphite melting point and why

Answer 13

high because it has strong covalent bonds that need a lot of energy to break

Question 14

graphite electrical conductivity

Answer 14

conducts electricity because it has delocalised electrons (4th electron of each carbon atom becomes delocalised)

Question 15

graphite uses and why

Answer 15

uses - pencils, lubricant

why - the layers can slide over each other because there are no covalent bonds between them, making it soft and slippery

Question 16

graphite structure

Answer 16

giant covalent

Question 17

diamond melting point and why

Answer 17

high because it has lots of strong covalent bonds

Question 18

diamond electrical conductivity and why

Answer 18

doesn’t conduct electricity because it has no delocalised electrons

Question 19

diamond uses and why

Answer 19

uses - gemstones, drill bits, glass cutting

why - carbon atoms are held together by strong covalent bonds, making it hard

Question 20

diamond structure

Answer 20

giant covalent

Question 21

bonding between magnesium and fluorine

Answer 21

ionic

Question 22

bonding between magnesium and oxygen

Answer 22

ionic

Question 23

sulfur and hydrogen bonding

Answer 23

covalent

Question 24

calcium and oxygen bonding

Answer 24

ionic

Question 25

carbon and hydrogen bonding (methane)

Answer 25

covalent

Question 26

carbon and oxygen bonding

Answer 26

covalent