INVESTIGATION 1 Copper Turnings + Nitric Acid What do you observe? -A reaction takes place and the clear acid together with the Copper, start to turn a bluish green After 2 minutes? -A Brownish red gas is released. This gas is Nitrogen Dioxide. (Should do the experiment in a fume cupboard) CONCLUSION Copper turnings plus Nitric acid produce toxic Nitrogen Dioxide gas. Copper Turnings + Nitric Acid => Copper Nitrate + Water + Nitrogen Dioxide Cu(s) + 4HNO 3 (aq) -> Cu(NO 3 )2(aq) + 2NO 2 (g) + 2H 2 O(l)

INVESTIGATION 2 Potassium Permanganate (KMnO 4 ) added to: -Tap water - Hot water What do you observe? (TAP WATER) -The potassium permanganate diffuses slowly into the tap water and turns it purple What do you observe? (HOT WATER) -The potassium permanganate diffuses quickly into the tap water and turns it purple CONCLUSION If the water temperature is higher, then the rate of diffusion will increase.

INVESTIGATION 3 Volume of Salt and water What do you observe? - When sodium chloride dissolves in water to make a saturated solution there is a reduction in volume. CONCLUSION If you add two substances (e.g. Salt and water), you cannot necessarily just add their original two volumes together to get the final volume. Sodium and chlorine atoms in their crystalline array take up more room than when they are separated.

INVESTIGATION 4 Syringe with air versus water What do you observe? (AIR) - The syringe plunger moves noticeably and the air in the syringe can be compressed What do you observe? (WATER) - The plunger of the syringe barely moves and the water is hardly compressed CONCLUSION Air can be squeezed into a smaller space; it is compressible. Air can't be squeezed so much that it takes up no room at all. Note: Liquids and solids are compressible, but only to a tiny degree in comparison with air or gases in general.

INVESTIGATION 5 Ammonia plus Hydrochloric Acid CONCLUSION NH 3 + HCl --> NH 4 Cl (ammonium chloride) After about a minute the gases diffuse far enough to meet and a ring of solid ammonium chloride is formed. The ring of Ammonium Chloride, usually forms nearer to the hydrochloric acid end of the tube because hydrogen chloride diffuses more slowly than ammonia

INVESTIGATION 6 Ice cubes melting Graph of Temperature versus time What happens to the temperature of a block of ice when you put a Bunsen burner underneath it? You might think that the temperature goes up smoothly, but that's not what happens. The graph of temperature against time is called a heating curve.

CONCLUSION When a solid is melting the heat energy added is building up the potential energy of the molecules to break the electrical forces holding them together. Similarly, when liquids are turning to gases the heat energy increases the energy of the molecules so they get further apart and become gas molecules.

INVESTIGATION 7 Heating a crystal of Iodine What do you observe? The iodine crystals sublimate and change directly into a gas (rich purple vapour) CONCLUSION Iodine crystals turn directly into gas upon heating without going through the liquid state. The scientific term for the process of converting from a solid to a gas, without transitioning through a liquid phase, is "sublimation.“

DEFINITIONS MELT - The process of going from a solid state to the liquid state. FREEZE – Conversion of a liquid to a solid (Freeze is used for water to ice, we can also use the word Solidify EVAPORATE - to change from a liquid or solid state into vapour/ gas. CONDENSE – to be reduced from a gas or vapour to a liquid SUBLIME – to convert a substance from the solid state directly to vapour / gas by heat e.g. dry ice

1)Precipitation Clouds lose their water as it falls to the ground. This phenomenon is called rain or precipitation. 2) Infiltration Rainwater infiltrates into the ground and sinks to the saturated zone, where it becomes groundwater. Groundwater slowly moves from places of high elevation to places with low elevation. 3) Transpiration Plants and other forms of vegetation take up water from the soil and excrete it again as water vapour. 4) Surface run-off The rainwater that does not infiltrate into the soil will directly reach the surface water, as it will run-off to rivers and lakes. After that it will be transported back to the seas and oceans. This water is called surface run-off. 5) Evaporation Due to the influence of sunlight the water in oceans and lakes will warm up. As a result of that it will evaporate and rise up into the atmosphere. There it will form clouds that will eventually cause rainwater to fall back on earth. 6) Condensation In contact with the atmosphere the water vapour will transform back to liquid, so that it will be visible in the air. These accumulations of water in the air are what we call clouds.