Solutions

A solution is when a substance is dissolved in another substance. A successful solution has the solute mixing freely in the solvent.

Preliminary action,

make tea in a beaker or in small petri dishes observe a small number of coffee granules diffuse.

Some water was placed in a beaker, and its mass was measured using a balance.The mass of water was 200 g. Then 11 g of sugar was weighed out. The sugar was added to the water, and sank to the bottom. 10 minutes later the sugar could not be seen.

Carry out this claim and see if it is true

Calculate the density of this mix

What is happening when sugar or salt get dissovled in water.

http://www.chemit.co.uk/default.aspx?sitemapID=57

A Solution is made up of a Solute (usually solid) dissolved in a Solvent (usually the solvent is liquid)

The mass of Solvent is greater than the Solute

water as a solvent

water the universal solvent

carry out experiments on water and publish them globally

http://water.chemistry2011.org/web/iyc/home

OC14 use cobalt chloride paper or

anhydrous copper sulfate to test for water

Cobalt(II) chloride refers most commonly to the inorganic compound with the formula CoCl2·6H2O, which when hydrated is deep rose. Because of this dramatic color change and the ease of the hydration/dehydration reaction, "cobalt chloride" is used as an indicator for water in desiccants. The rose hexahydrate is one of the most common cobalt compounds in the laboratory.

http://en.wikipedia.org/wiki/Cobalt(II)_chloride

*Cobalt Chloride is on the banned substance list*

is blue when it is dry

and

pink when it is in the presence of water!

Anhydrous Copper Sulphate is White

When it comes into contact with water it goes blue (and become hydrous)

You could also use white anhydrous copper sulphate which will turn blue in the presence of water

OC15 investigate the solubility of a variety of substances in water and the effect of temperature on solubility

OC15 (expt) To test the Solubility of different substances

Apparatus

Beakers, water, Oil, Sand, Sugar, salt, copper sulphate, chalk (calcium carbonate), calcium sulphate, potassium permanganate, sodium carbonate, sodium fluorescene, sodium bicarbonate

Method

  1. Add 200ml of water to many different beakers
  2. Add one substance to each different beaker
  3. Stir the contents
  4. Decide if the substance has dissolved or not

Results

Conclusions

Water is known as the universal solvent, because it dissolves most substances.

Some solutions are mixtures of two or more different solutes in a solvent, usually water.

A super saturated solution is one that holds more solute than it should be able to at a certain temperature.

OC15 (expt) To investigate the effect of temperature on solubility

  1. Find the mass of a dry beaker
  2. Add some water, find the mass of the beaker and water
  3. Add some substance and stir until it becomes dissolved
  4. Add more substance until some remains at the bottom
  5. Take the temperature of the Solution
  6. Heat the solution by 10oC
  7. Repeat steps 3 - 6 until the temperature gets above 60oC
  8. Fill your conical flask to the 100ml mark with distilled water
  9. Place the Conical flask on the scales, find its mass, write it down.
  10. Add some of your substance to the weigh boat (a few spatulas)
  11. Add it to the water
  12. Swirl the solution
  13. Does your substance fully dissolve?
  14. Repeat steps 3 to 7 until the substance does not dissolve any more.
  15. Place the Conical flask on the scales again, find its mass, write it down.

Mass of weigh Boat ______g

Add up the total masses

Conclusion

the solubility of substance is ___ grams per 100 ml of pure water

solubilities

NaCl 359g / l

CuSO4 361 g/l

OC16 examine the difference between a dilute, concentrated and saturated solution

A Concentrated solution is one that has a lot of Solute per unit volume of Solvent

A Dilute solution is one that has little solute per unit volume of Solvent

A Saturated solution is when solution holds as much solute as it can, any extra falls to the bottom

A Super Saturated Solution is one that holds more solute than it should at the temperature it is at.

OC17 grow crystals using alum or copper sulfate

try it out from here ??

http://www.practicalchemistry.org/experiments/making-a-crystal-garden,193,EX.html

Method

  1. Dissolve some crystal making substance in some water.
  2. Mix so the substance is completely dissolved
  3. Pour a little of the solution into evaporating dishes
  4. Heat the Evaporation dishes with the solution (what will happen??)
  5. Stop heating when very little liquid is left.
  6. Observe.

Results

Draw a diagram of the Crystals

Conclusions

Copper Sulphate forms crystals when the excess water is removed, and goes white if the crystals are heated to much.

What dissolves ? (might be good after ionic bonds)

http://www.sciencebyjones.com/solubility_rules.htm

D5: Blue Glow

A colourless liquid and a blue liquid when mixed together emit a blue

chemiluminescent glow. Light sticks are devices that produce a 'coolight' by means

of a similar chemical reaction.

l Preparation time 30 minutes

l Demonstration time less than five minutes

Requirements

4 g sodium carbonate (anhydrous), Na2CO3

3 litres of distilled water

0.2 g luminol (3-aminophtalhydrazide), C8H7O2N3

24 g sodium hydrogencarbonate NaHCO3

0.5 g ammonium carbonate monohydrate, (NH4)2CO3.H2O

0.4 g copper(II) sulphate pentahydrate, CuSO4.5H2O (harmful)

50 cm3 10 vol. hydrogen peroxide, H2O2

2 x 1 litre flasks

3 litre conical flasks or round bottomed flask with rubber stoppers

glass funnel (15-20 cm in diameter)

ring stand and glass spiral or transparent tubing (see diagram)

Method

Solution A

Dissolve 4.0 g of sodium carbonate in 500 cm3 of distilled water.

Add 0.2 g of luminol and stir to dissolve. Add 24 g of sodium hydrogencarbonate,

0.5 g of ammonium carbonate and 0.4 g of copper sulphate. Stir until all the solid dissolves.

Dilute to a final volume of 1 litre with distilled water. The pH of this

solution will be around 9.

Note: this solution must not be made more than 10 minutes in advance of the demonstration.

Solution B

Dilute 50 cm3 of 10 vol. hydrogen peroxide to 1 litre with distilled water.

Set up a funnel and spiral apparatus either using a glass spiral or transparent tubing

coiled around a set of clamps. See diagram on page 92.

Demonstration

1 Dim the lights but allow sufficient light to see what you are doing! Slowly pour

solution A and B simultaneously into the funnel. A strong blue glow will be

observed.

2 Continue pouring until both flasks are empty. The glowing liquid runs through the

spiral and collects in the 3 litre conical flask. The solution will continue to glow

for approximately 2 minutes after it first exits the spiral.

3 Flush out the coil with water as soon as possible, before disconnecting the

apparatus.

Take a clean beaker, keeping it dry fill the beaker as high as will not spill.

Place the beaker on some paper tissue

A beaker is filled to the brim with water,

slowly sprinkle 20 grams of salt into the beaker

what do you think will happen ?

What happened?

Solutions are different chemicals mixed,

these substances must be miscible to make a solution

Measure out 50 cm2 of Water

Measure out 50 cm2 of Alcohol.

What will happen when you pour one measure on the other ?

Do it and observe.

Answer,

Measure out 150 cm2 of peas,

Measure out 150 cm2 of rice,

What will happen when you pour one measure on the other ?

place in beaker shake and settle.

What do you notice?

Why does this happen?

Is it the same for the water and alcohol

Why does this happen? .... molecules

Some materials do not dissolve in water they are said to be immiscible.

Immiscible liquids i.e. liquids that do not mix, liquids that will remain separated e.g. water, oil and mercury

How much co2 is in a fizzy drink?

Find mass of bottle of pop

Find mass of beaker

open bottle

Find mass of bottle of pop

gentaly pour drink into beaker,

find mass of beaker and pop

find mass of empty bottle

add in 2g additions salt.

This could be expanded by testing the same on sugar,

How could you find the amount of sugar in a bottle of fizzy drink??

O2 and CO2 concentrations in water

Gas collecting apparatus, Test tubes, Lime water, Splint, Hot plate

Boil the water

Collect and test for both gases

Record results.

Solubility of O2 in water at different temperatures.

Water sample. Hot plate. Gas collecting apparatus. Graduated test tubes.

Choose three different temps.

Replace graduated test tube for each increase in temp.

Test for O2.