PARTICLE MODEL OF MATTERWorksheet answers

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) + 4HNO3(aq) -> Cu(NO3)2(aq) + 2NO2(g) + 2H2O(l)

INVESTIGATION 2Potassium Permanganate (KMnO4) 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 3Volume 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 4Syringe 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 5Ammonia plus Hydrochloric Acid

CONCLUSION

NH3 + HCl --> NH4Cl (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 6Ice 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 7Heating 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 theliquid state.

The scientific term for the processof 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) PrecipitationClouds lose their water as it falls to the ground. This phenomenon is called rain or

precipitation. 2) InfiltrationRainwater 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) TranspirationPlants and other forms of vegetation take up water from the soil and excrete it again as water vapour. 4) Surface run-offThe 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) EvaporationDue 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) CondensationIn 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.