Chemistry.txt

A reaction that takes in energy from the surroundings, usually shown by a fall in temperature

A substance with a pH less than 7

A base is a substance with a pH higher than 7, and alkali is a base which dissolves in water

A reaction that transfers energy to the surroundings, usually shown by a rise in temperature

A dye which changes colour depending on whether it's above or below a certain pH

Aqueous, a substance dissolved in water

A substance which speeds up a reaction without being changed or used up in the reaction

Solid catalysts work by giving reacting particles something to stick to which increases the successful number of collisions

For commercial reasons, they increase the rates of reactions which saves money, as reactions require less energy

They are expesive to buy, and often need to be removed from the product and cleaned, different reactions require different catalysts, they are easily denatured

Increasing the temperature increases the speed of the particles and so they collide more often

There are more particles of a reactant so there are more frequent collisions between reactant particles

The particles are compact closer together so there will be more frequent collisions

Particles in the solution will have more area to work on so there will be more frequent collisions

• Reactant used/ product formed
• _____________________
• time

The minimum amount of energy needed by particles to react

OH-

H+

Copper chloride + water

Ammonia dissolves in water to make an alkaline solution, which is reacted with nitric acid, to get the salt- ammonium nitrate

Fertiliser, it is good as it has nitrogen from two sources, plants need nitrogen to make protiens

False

Insoluble

Precipitation reaction- mix two solutions containing ions and filter the salt from the reacted solution

The mass number

The bottom number on the atomic symbol- the number of protons and electrons in an element

Different atomic forms of the same element, with the same number of protons but a different number of neutrons

The relative formula mass in grams is known as one mole of that substance

The same as the mass number of an element (top number)

• Mass in g (of element or compound)
• ____________________
• Relative formula mass

42/12 =3.5 moles

Substances in which atoms of two or more elements are chemically bonded together

Transferring or sharing electrons in the highest occupied energy levels (shells) of atoms in order to achieve the structure of a noble gas

Atoms lose or gain electrons to form charged particles (ions) which become strongly attracted

Atoms share electrons with other atoms from the outer shell to form the state of a noble gas with its outer shells full

Alkali metals all react with non metals to form ionic compounds- the metal ion has a single + charge

Halogens all react with group 1 alkali metals to form ionic compounds- single - charge

By strong electrostatic forces between oppositely charged ions- these forces act in all directions in the lattice

In a regular cuboid lattice

• High melting points
• High boiling points
• Dissolve easily

4

• Low melting/ boiling points
• Don't conduct electricity

Weak

Lattice

Strong

• Diamond
• Graphite
• Silicon dioxide

They are delocalised (free)- these electrons hold the atoms together in a regular structure