Topics 1.1 and 1.2

Question 1

elements

Answer 1

primary constituent of matter that cannot be broken down into simpler substances

Question 2

compounds

Answer 2

atoms of different elements chemically bonded together in a fixed ratio

Question 3

mixtures

Answer 3

more than one elemnt or compound in no fixed ratio, not chemically bonded thus can be seperated by physical methods

Question 4

how do you carry out filtration

Answer 4

filtration is used to seperate a solid from a liquid, or a soluble solid from an insoluble solid by dissolve them in a liquid beforehand
you need a conical flask, a filter paper and a filter funnel where the solid which remains in the filter paper is called the residue, and whatever passes through the filter paper into the conical flask is the filtrate

Question 5

how do you carry out evaporation

Answer 5

used to seperate a solid from a liquid
where you heat the mixture and the liquid will evaporate, the solid remains

Question 6

how do you carry out distillation

Answer 6

used to seperate two liquids with different boiling points, the liquid with the lowest boiling point evaporates first and will pass through a condenser where it is turned back into a liquid and collected at the opposite end of the distillator

Question 7

how do you carry out chromotography

Answer 7

seperates componentss of a mixture, you must draw a baseline on the filter paper using a pencil, and place your mixture on the baseline, you then place you filter paper in a solvent which musnt reach the baseline. your different mixtures will move along the filter paper might need a locating agent to view, and you can then calaculate the rf value by dividing the total distance the individual component traveled from the baseline by the total distance traveled by the solvent

Question 8

what is meant by homogeneous

Answer 8

A type of mixture that a uniform composition and no visible phases or boundaries
meaning that the components of the mixture are equally distributed and in the same state, making the composition the same throughout the mixture

Question 9

what is meant by heterogeneous

Answer 9

A type of mixture with a non-uniform composition with visible phases or boundaries.

Question 10

kinetic molecular theory

Answer 10

a model to explain physical properties of matter (solid, liquids and gases) and changes of state

Question 11

what are the endothermic changes of state

Answer 11

melting, boiling, sublimation
energy is taken in to break the bonds and change state

Question 12

what are the exothermic changes of state

Answer 12

freezing, condensation, deposition
energy is released into the surroundings

Question 13

what is sublimation

Answer 13

solid to gas

Question 14

what is deposition

Answer 14

gas to solid

Question 15

formula to convert celsius to kelvin

Answer 15

celsius + 273 =kelvin

Question 16

what is temperature in kelvin an average measure of

Answer 16

kinetic energy of particles

Question 17

describe an atoms nucleus

Answer 17

positvely charged dense nucleus composed of neutrons and protons

Question 18

where do negatively charged electrons occupy

Answer 18

occupy the space around a nucleus

Question 19

in nucleur symbol notation what does A and Z stand for

Answer 19

A= mass number
Z= atomic number

Question 20

how do you calculate number of protons neutrons and electrons from A and Z

Answer 20

Z= number of protons= number of electrons (in an atom)
number of neutrons= A-Z

Question 21

what are the masses of proton neutron and electron

Answer 21

proton= 1
neutron=1
electron= negligible

Question 22

what are the charges of proton neutron and electron

Answer 22

proton= +1
neutron= 0
electron= -1

Question 23

isotopes

Answer 23

atoms of the same element with different number of neutrons

Question 24

how do calculate relative atomic masses

Answer 24

mass number of each isootope is multiplied by its abundance and all of them are added together
they are then divided by 100

Question 25

can there be differences in physical properties of isotopes

Answer 25

yes

Question 26

why are mass spectra used

Answer 26

to determine the realtive atomic masses of isotopes from their isotipic compositions