chemistry test

• Boiling point: 100ºC
• Frezzing point: 0ºC
• Heat capacity: 4.2Jg-1ºC-1 (4.2 joules of energy is required to heat up one gram of water by one degree)
• Solubility: ability to dissolve other substances

• It expands
• It becomes less dense, this is due to the alignment of every hydrogen atom with oxygen atoms. This means there is space created inbetwen H2O molecules.

• 4.2 joules
• 4.2Jg-1ºC-1

Water molecules pull other molecules apart if they are polar and are attracted. Then the water molecules surround the atom and it 'disapears'.

• Water: 4.2
• Ethanol: 2.4
• Iron: 0.45
• Lead: 0.13
• Copper: 0.39
• Sand 0.48

remember

• g/100g
• g/litre
• M/moles/litre

C1V1=C2V2 for dilution

Solutions that are no longer soluble form a crystalisation this could be due to temperature change.

It is a solution that contains more dissolved solutes than a saturated soultion. Any point above the solubility curve.

When two solutions are mixed and a solid id formed

An equation were the spectator ion are omitted

It is the process by which small particles suspended in the water join together to form larger heavier particles the sink to the bottom. This is achieved by adding aluminium sulfate and sometimes lime (to neutralise acids and provide a source of hydroxide ions).

• Lime
• Ca(OH)2(s)--->Ca(aq)+2OH(aq)

• Aluminium sulfate
• Al(aq)+3OH(aq)--->Al(OH)3(s)
• Aluminium hydroxide is produced in the form of gelatinous precipitate called floc, which traps other fine particles and removes color and some microorganiams from the water.

When the water is left to stand leting the floc settle to form sluge.

Water from the settling tank is allowed to filter down through a bed of sand over gravel. This removes any suspended matter.

• After filtering, the clean water is usually treated with gaseous chlorine to destroy bacteria. Chlorine reacts with water.
• Cl2(g)+H2O(l)--->HOCl(aq)+H(aq)+Cl(aq)

Where more soap need to be used to produce a lather. It i caused by the presence of some metal ions, mainly calcium, magnesium and iron.

The process of removeing salts from sea water in order to produce fresh water. There are three ways of doing this, though distillation, reverse osmosis and ion exchange.

• Polar covalent compunds that can form hydrogen bonds with water
• Polar covalent molecular compounds that ionise
• Ionic compounds

• hydrogen bonds between water molecules are broken
• hydrogen bonds between eg ethanol molecules are broken
• hydrogen bonds between water molecules and ethanol molecules are formed

• polar covalent bonds within molecules are broken, production hydrogen ions and anions
• a covalent bond forms between each H+ and an H2O molecule, giving H3O+ ions. Ion-dipole attractions between the newly formed ions and the pola water molecules are formed.

• ionic bonds within the soild are broken
• hydrogen bonds between water molecules are broken
• ion-dipole attractions between the ions and the polar water molecules are formed

millilitre÷10^3=litre

n=C*V

c=n/v

n=m/M