Formulae. Equations And Amount Of Substance

Front 1

ELEMENT

Back 1

Cannot be broken down into simpler substances by either physical or chemical means

Hint 1

Can exist as atoms (Na) or as molecules (Nitrogen, N2)

Front 2

MOLECULE

Back 2

It is the smallest electrically neutral particle, of an element or compound that can exist on its own.
Example: water (H2O) - compound / oxygen (O2) - element
It is also the name given to the smallest part of those elements which do not exist as atoms in the free state
Example: hydrogen H2, Nitrogen N2, F2, Cl2, Br2

Hint 2

Ionic compounds do not exist as molecules

Front 3

Ion

Back 3

An atom or group of atoms which carry an electrical charge

Front 4

COMPOUND

Back 4

A substance formed when two or more elements chemically combine together

Hint 4

Have properties that are different from its component elements
Can be broken down into simpler substances by chemical methods.

Front 5

ISOTOPES

Back 5

Atoms of the same element having same proton number but different neutron number
Example: 35-Cl and 37-Cl

Hint 5

Front 6

Empirical Formula

Back 6

Smallest whole number ratio of atoms in a compound

Front 7

Molecular Formula

Back 7

Actual number of atoms in a compound

Hint 7

1) Calculate empirical Formula mass
2) divide molecular mass by empirical formula mass
3) Molecular Formula = (empirical formula)*n

Front 8

Atomic Mass unit

Back 8

Mass of a carbon-12 atom divided by 12. This is the standard reference scale to measure mass of atoms and molecules

Front 9

Relative Atomic Mass

Back 9

The weighted average mass of an atom of that element divided by the 1/12th the mass of a carbon-12 atom.

Front 10

Relative molecular mass

Back 10

The sum of the relative Atomic Masses of all the atoms in the chemical formula

Front 11

Relative Isotopic Mass

Back 11

The mass of an atom of that isotope divided by 1/12th the mass of a carbon-12 atom

Front 12

Mole

Back 12

Amount of substance which contains the same number of particles (atoms, ions, molecules) as there are carbon atoms in 12g of carbon-12)

Front 13

Avogardro's Constant

Back 13

The number of particles in a mole
1 mole = 6.02x10²³ particles (atoms ions or molecules)

Front 14

Molar mass

Back 14

Molar mass of a substance is the mass of one mole in grams

Hint 14

Number of moles = mass in grams / molar mass of atoms

Front 15

Molar volume

Back 15

Volume occupied by one mole at room temperature and pressure
=24dm³ at rtp

Hint 15

Number of moles = volume of gas / molar volume

Front 16

Concentration

Back 16

Measured in moles per cubic decimeter (mol/dm³)
1 litre = 1 dm³ = 1000 cm³

Front 17

1M [of NaCl]

Back 17

Means that each dm³ of the solution contains 1 mole (58.5g) [of NaCl]
OR ITS CONCENTRATION IS 1 mol/dm³

Front 18

Molarity

Back 18

Concentration in mol/dm³

Hint 18

Molarity = moles of solute / volume of solution

Front 19

Conversion to g/dm³

Back 19

Molarity x molar mass of solute

Front 20

Parts per million

Back 20

Hint 20

Equivalent to one milligram of something per kg of solvent

Front 21

Salts

Back 21

Consist of lattice of positive and negative ions
Salts with water of crystallisation are hydrated salts
Formed by the reaction between an acid and a base

Front 22

Double Salts

Back 22

Crystals that contain two different salts (two different anions or cations)

Mixing two different salts and crystallising it would form a double salt
Example: when iron (II) sulfate solution is mixed with ammonium sulfate solution, the salt ammonium iron (II) sulfate is formed
It can also be formed from raw materials using iron, ammonia, and sulfuric acid

Front 23

Percentage yield

Back 23

Used to measure the efficiency of a reaction.

Front 24

Theoretical yield

Back 24

Mass of product that should be formed

Hint 24

Can be calculated using mass of reactants and chemical equation

Front 25

Actual yield

Back 25

Experimental yield - actual mass of product formed
Always less than the theoretical yield. Because
~all the reactants do not undergo complete reaction
~some product is lost during handling
~solution loss during filtration or during transfer between containers

Front 26

Atom Economy

Back 26

Also used to measure efficency of reaction.
It is a measure of the proportion of reactant atoms that become a part of the desired products rather than by products

Hint 26

A reaction that has a very high yield could still be very wasteful if a lot of the atoms of the reactants form other products

Front 27

Atom Economy in addition and substitution reactions

Back 27

Addition reactions have 100% atom economy since ONLY ONE PRODUCT is formed and NO atoms are WASTED AS BY-PRODUCTS

Substitution reactions have lower atom economy than addition reactions since at least two products will be formed, where only one product is the desired product