IB HL CHEMISTRY - structure 1.1 (introduction to particulate model of matter)

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what is the atomic theory?

all matter is composed of atoms and it cannot be created or destroyed

what is matter

any substance that occupies space and mass

what is a pure substance?

has definite and uniform composition

what is an element

substance which only contains one type of atom and is uniform

what is a compound

any two substances chemically bonded in a fixed ratio

what is a mixture

a combination of 2+ pure substances which are not chemically bonded and retains their individual properties

what is a homogenous mixture

uniform composition and properties

what is a heterogeneous mixture

non uniform composition and properties are not evenly distributed

what does aqueous mean?

molecules dissolved in aqueous solutions

What is sublimation

solid to gas

what is deposition

gas to solid

what is condesnation

gas to liquid

what is vaporisation

liquid to gas

what is an exothermic state change

when particles move from a less condensed state to a more condensed state, so IMFS become stronger

what is an endothermic state change

particles moving from a more condensed state to less condensed state , so energy is absorbed by surroundings

What happens at 0 K?

particles cannot transfer any kinetic energy upon collisions, which means that they cannot lose any more heat and become colder

What are the 5 methods of seperating mixtures

• filtration

• crystallisation

• chromatography

• distillation

• dissolution

How do you calculate the RF value?

distance travelled by solvent/distance travelled by solute

How does the soluability of substances vary in chromatography?

more soluable substances will be more attracted to the stationary phase

what does the affinity of a solvent depend on?

intermolecular force between paper and solvent

what is the mass number?

number of protons in the nucleus

what is atomic mass?

mass in grams in 1 mole of a substance

what is relative atomic mass?

weighted average of all isotopes relative to 1/12 of a c12 atom

what are properties of an isotope?

• same number of protons

• same electron configurations for similar chemical reactions

• different melting and boiling points

• different atomic mass

How many electrons are in each orbital? (s,p,d,f)

2,6,10,14

What are the 2 exceptions to electronic configuration?

chromium and copper

What is the condesned configuration for copper?

[Ar] 4s1 3d10

what is the condensed configuration for chromium?

[Ar]4s1 3d5

what are the 3 principals when filling up electrons?

electrons will lower energy levels first

no more than 2 electrons can occupy the same orbitals, and they must have opposite spins

electrons always enter an empty orbital before they pair up

what is ground state?

lowest energy level