module two: foundations in chemistry

Question 1

atoms consist of

Answer 1

nucleus - protons, neutrons
electrons - occupied a region outside the nucleus arranged in shells

Question 2

mass of an electron

Answer 2

1/1836th mass of a proton

Question 3

isotope

Answer 3

atoms of the same element with different numbers of neutrons and different masses

Question 4

relative isotopic mass

Answer 4

the mass of an isotope relative to 1/12th of the mass of carbon-12

Question 5

relative atomic mass

Answer 5

the weighted mean mass of an atom relative to 1/12th of the mass of carbon-12

Question 6

atomic orbital

Answer 6

region around the nucleus that can hold up to 2 electrons with opposite spins

Question 7

shape of s-orbital

Answer 7

spherical

Question 8

shape of p-orbital

Answer 8

dumbell

Question 9

simple molecular elements

Answer 9

H2, N2, O2, F2, Cl2, Br2, I2, P4, S8

Question 10

metallic elements

Answer 10

Mg, Fe, Na, Ni

Question 11

giant covalent elements

Answer 11

diamond, graphite (carbon)
Si

Question 12

simple molecular compounds

Answer 12

CO2, CO, NO2, NO, SO2, SO3, NH3, CH4, H2S

Question 13

giant covalent compounds

Answer 13

SiO2

Question 14

pV = nRT

Answer 14

p = pressure (Pa)
V = volume (m^3)
n = number of moles
R = gas constant (8.314)
T = temperature (K)

Question 15

metal + acid

Answer 15

salt + hydrogen

Question 16

metal oxide + acid

Answer 16

salt + water

Question 17

metal carbonate + acid

Answer 17

salt + water + carbon dioxide

Question 18

strong acid

Answer 18

fully dissociates in water
releases all its hydrogen atoms
e.g. HCl, HNO3

Question 19

weak acid

Answer 19

partially dissociates in water
releases a small proportion of its hydrogen atoms
e.g. CH3COOH

Question 20

why do covalent bonds have low melting/boiling points

Answer 20

little energy is req. to overcome the weak intermolecular bonds between the separate molecules

Question 21

conductivity in ionic compounds

Answer 21

cannot conduct electricity in solid state as ions ar immobile and cannot carry a charge
can conduct electricity when molten or aqueous as ions are free to move and carry a charge

Question 22

why do ionic compounds have high melting/boiling points

Answer 22

high temperatures are needed to prove the large amount of energy req. to overcome the strong electrostatic attraction between the ions

Question 23

why do ionic compounds dissolve in water

Answer 23

water is polar
polar water molecules break down the lattice and surround each ion in solution

Question 24

shape of:
2 bonding pairs, 0 lone pairs

Answer 24

linear
CO2

Question 25

shape of:
3 bonding pairs, 0 lone pairs

Answer 25

trigonal planar
BF3

Question 26

shape of:
2 bonding pairs, 1 lone pair

Answer 26

non-linear
SO2, NO2

Question 27

shape of:
4 bonding pairs, 0 lone pairs

Answer 27

tetrahedral
CH4

Question 28

shape of:
3 bonding pairs, 1 lone pair

Answer 28

trigonal pyramid
NH3

Question 29

shape of:
2 bonding pairs, 2 lone pairs

Answer 29

non-linear
H2O

Question 30

shape of:
5 bonding pairs, 0 lone pairs

Answer 30

trigonal bipyramid
PF5

Question 31

shape of:
3 bonding pairs, 2 lone pairs

Answer 31

trigonal planar
ICl3

Question 32

shape of:
6 bonding pairs, 0 lone pairs

Answer 32

octahedral
SF6

Question 33

shape of:
5 bonding pairs, 1 lone pair

Answer 33

square pyramid
IF5

Question 34

shape of:
4 bonding pairs, 2 lone pairs

Answer 34

square planar

Question 35

linear bond angle

Answer 35

180°

Question 36

how can the atom economy of a reaction be improved

Answer 36

changing a reaction to have fewer waste products
finding a use for the waste products