mod 1

Question 1

what is a homogenous mixture?

Answer 1

all components are uniformly mixed and the composition is uniform (completely mixed) plus “uniform” means one so all the particles look the same and well blended

Question 2

what is a heterogenous mixture?

Answer 2

the components are not completely mixed, not uniform (you are able to see particles e.g ice cream, chocolate chip cookies, a jar of jelly beans etc)

Question 3

sieving

Answer 3

the method of solid particles of different particle size e.g separating rocks from sand (different particle sizes)

Question 4

centrifugation

Answer 4

separating solids from a different particle size in an AQUEOUS suspension. they separate because the denser particles are forced to the bottom while the lighter ones stay at the top. even red blood cells get centrifuged

Question 5

filteration

Answer 5

this is a method that can be used to separate solids that are already suspended in liquids or solutions e.g sand and salt can be separated by adding water to dissolve the salt and then filtering the mixture

Question 6

insoluble

Answer 6

not being able to dissolve e.g sand cannot dissolve in water

Question 7

soluble

Answer 7

capable of being dissolved in some solvent, usually water e.g salt actually dissolves in water

Question 8

evaporation

Answer 8

common procedure used to separated the components of a solution, usually, boiling point is a good indicator of evaporation…

water has a boiling point of 100 degrees, salt has a boiling point of 1465 degrees.

water will evaporate first, separating from salt

Question 9

miscible

Answer 9

liquids that mix in all proportion to form one phrase

Question 10

decantation

Answer 10

separating different liquids by their different densities! e.g oil and water.

different from centrifuge (separating solid from liquid)

Question 11

distillation

Answer 11

distillation, process involving the conversion of a liquid into vapour that is subsequently condensed back to liquid form

Question 12

groups

Answer 12

periodic table has 8 groups (arranged vertically - column)

Question 13

periods

Answer 13

each row in the periodic table is a period, AS YOU MOVE DOWN PERIODS, ELEMENTS BECOME MORE REACTIVE

Question 14

group 1 trends

Answer 14

alkali metals

Question 15

group 2

Answer 15

alkaline metals/transition metals

Question 16

group 3

Answer 16

semi metals

Question 17

isotopes

Answer 17

number of neutrons may be different, however, it has the same amount of protons and electrons (same net charge too)

Question 18

why do different elements emit different wavelengths of light?

Answer 18

discrete energy levels associated with an atom

Question 19

flame test

Answer 19

light is emitted when excited electrons move back to their ground state

Question 20

bohr model

Answer 20

electrons exist in orbitals, requiring energy to jump between orbitals (think of electrons orbiting around the nucleus, the sun) it also releases energy when the energy decrease

the bohr models explained why there were specific emission of atoms, only explained by discrete shells

Question 21

schrodinger model

Answer 21

built on from the bohr model into an entirely quantum model (electrons didnt have defined orbits)

Question 22

state of matter

Answer 22

-elements on the left hand side of the periodic table are solid at room temperature (metals)
-non-metals (right hand side of periodic table) can be either solid, liquid or gas at room temperatures

hydrogen is a gas at room temperature

mercury and bromine are liquids at room temperature

Question 23

electronegativity

Answer 23

determines how likely for an atom to attract an electron

-moving across a period increases electronegativity
-moving down a group decreases electronegativity

note: the greater the radii, the less electronegative an atom will be, this is because the nucleus and valance shell attract each other less

Question 24

first ionisation energy

Answer 24

required to “rip” an electron from the neutral atom; the energy to move the first electron

-moving down a group decreases ionisation energy (less effort for greater atomic radii)
-moving across a period increase ionisation energy

Question 25

reactivity

Answer 25

-moving down a metallic group, electrons become much more reactive

-in metals, moving down a group increases reactivity
-in metals, moving across a period decreases reactivity

Question 25

reactivity

Answer 25

-moving down a metallic group, electrons become much more reactive

-in metals, moving down a group increases reactivity
-in metals, moving across a period decreases reactivity

Question 26

reactivity

Answer 26

-moving down a metallic group, electrons become much more reactive

-in metals, moving down a group increases reactivity
-in metals, moving across a period decreases reactivity

Question 27

ionic bonding

Answer 27

ionic bonding generally occurs between metals (not electronegative) and non-metals (very electronegative)

-transfer of electrons between atoms

Question 28

covalent bonding

Answer 28

covalent bonding occurs when one atom shares its electrons with another atom

Covalent bonds usually occur between nonmetals. For example, in water (H2O) each hydrogen (H) and oxygen (O) share a pair of electrons to make a molecule of two hydrogen atoms single bonded to a single oxygen atom

Question 29

allotropy

Answer 29

Allotropy is a property that is exhibited by elements that exist in multiple forms and these elements have different atomic structures. An allotrope is a form of the element that has a different structure from the other form of the same element. They are different physical forms of a particular element

For example, graphite and diamond are both allotropes of carbon that occur in the solid state. Graphite is soft, while diamond is extremely hard.

Question 30

ionic networks

Answer 30

ionic substances are structured in a predictable, uniform way but the charge is neutral

ionic compounds are composed of a grid of alternating anions (negative ions) and cations (positive ions)

Question 31

covalent lattices

Answer 31

they are solid, and materials that are composed entirely of covalently bonded atoms, with “sheet” of lattice-like grids

usually not very hard, but are very malleable

Question 32

covalent networks

Answer 32

composed entirely of covalently bonded atoms, with ‘bonding’ spread continuously through the solids

-every atom is eventually connected with every other atoms
-covalent networks are usually very hard, with a high melting point

Question 33

metallic structure

Answer 33

metallic structures dont ‘chemically’ bond together

-metals clump together into recognisable shapes, with definite properties
-electrons no longer require a single nucleus to orbit around

-THEY FLOAT IN A SEA OF DELOCALISED ELECTRONS

-moves freely throughout the metallic structure, which is why metals are very conductive

Question 34

intermolecular bonds

Answer 34

intermolecular forces are the force of attractive/repulsion felt by one molecular/atom due to another molecule/atom

-determines how closely different molecular stick together and thus determines many physical properties of these molecules

Question 35

intramolecular forces

Answer 35

intramolecular forces are the forces of attractive/repulsion felt by one atom due to another atom e.g the intramolecular force holding the hydrogen atom to the oxygen atom with the same compound aka water

much stronger than intermolecular forces

Question 36

dipole-dipole