CHEM C2 & C3

Solid

Particles are closely packed in an orderly manner

Kinetic energy of particles is low

Attraction force between particles is strong

Liquid

Particles are closely packed but not in an orderly manner

Kinetic energy of particles is higher than solid state

Attraction force between particles is strong, but less than solid state

Gas

Particles are far apart

Kinetic energy of particles is very high

Attraction force between particles is weak

Melting point

Constant temperature when a substance changes from solid state to become liquid at a specific pressure

Freezing point

Constant temperature when a substance changes from liquid to solid state at a specific pressure

Heating curve of naphthalene

Melting occurs

No increase in temperature from B to C because heat energy absorbed by the particles is used to overcome the attraction force between particles until solids changes to liquid

Cooling curve of naphthalene

Freezing occurs

No decrease in temperature from F to G because heat energy that is lost to the surroundings is balanced by the heat energy released when the particles attract each other to form solid

John dalton

Atom

J.J Thomson

Electrons

Ernest Rutherford

Protons

Niels Bohr

Shells

James Chadwick

Neutron

Number of protons in the nucleus of an atom is known as

Proton number

Total number of protons & neutrons in the nucleus of an atom is known as

nucleon number

How to find nucleon number

Num of protons + num of neutrons // proton num + num of neutrons

Isotopes

atoms of the same element with the same number of protons but different number of neutrons // same proton number with different nucleon number

RAM

Σ(% isotope x mass of isotope) / 100

Number of particles

Num of mole = num of particles/6.02×10²³ = — mol

Mass (g)

Number of mole = mass of substance (g) / molar mass (RAM,RMM,RFM) = —g

Vol of gas

Room condition : num of mole = vol of gas / 24dm³/24000cm³

STP : num of mole = vol of gas / 22.4dm³/22400cm³

Qualitative info

Name of reactants & products

Quantitative info

Stoichiometry coefficient (big number in front)

Use of isotopes in medicine

Cobalt-60 - kill cancer cells w/o surgery in radiotherapy

Iodine-131 - treatment of thyroid disorders, e.g hyperthyroidism & thyroid cancer

Use of isotope in agriculture

Phosphorus-32 - study of plant metabolism

Use of isotope in nuclear

Uranium-235 - generating electricity thru nuclear power generator

Use of isotope in archaeology

Carbon-14 - estimation of artifacts or fossils age

Lead-210 - determine the age of sand & earth layers up to 80 years

Use of isotope in industry

Hydrogen-3 - a detector to study sewage & liquid wastes

Use of isotope in engineering

Sodium-24 - detects leakage in underground pipes

Define empirical formula

Simplest whole number ratio of atoms of each element in a compound