Non-Technology Research

The headline is: "Non-technology Research".

I chose this headline because today Mdm Riza brought us to the library to learn more about photosynthesis. At first, we have to discuss in groups on what we already knew on photosynthesis. After that, we have to share our ideas with the whole class. I have learnt more things after the sharing. The most important thing that I have learnt is the factors which are needed for photosynthesis to occur. The factors are: presence of light, water and carbon dioxide. Then, we were told to work in the same group and complete the questions given in the worksheet by either doing a mind-map or comic strip. We have to do our research on scientific journals / books / articles.

Going Through Term 3 Common Test

3 Thoughts:
1) I have learnt that mercury is a silvery metal which is a liqud at room temperature. Mercury is a good conductor of both heat and electricity. Mercury will become a solid when it is below its melting point(very low) while it will become a colourless gas when it is above its boling point(very high).
2) I have learnt that for filtration to work properly, the size of the holes on the filter paper must be very small so that insoluble substances, which are very small in size, such as pepper can be collected as the residue on the filter paper.
3) I have also learnt that if you want to get a mixture which has a very low melting point and a very high boiling point, the substances that are mixed together must also have the properties(low melting point and high boiling point).

2 Questions:
1) When we want to get a mixture which has low melting point and high boiling point, must all the substances which are mixed together have those properties(low melting point and high boiling point)? Or just one substance that has those properties will be enough?
2) Is the colour of the mercury different when it is at the solid state and at the liquid state?

1 Useful application:
1) We know that mercury is a liquid at room temperature, thus we must be careful when handling with thermometers as mercury is found in them. When we are not careful and drop the thermometer, the thermometer will crack and the mercury in it will flow out. It will be very difficult for us to collect back the mercury which is scattered on the floor as it is in the liquid state but not in the solid state and mercury is also poisonous. Hence, we cannot touch it with our bare hands.

Workbook- Chapter 6 Worksheet

3 Thoughts:
1) I have learnt that ethanol is a solvent which is a type of alcohol. When ethanol is mixed with another substance like iodine, they will form to become a mixture.
2) When using the fractional distillation method, the substance with the lowest boiling point will be found at the top most fraction as when the mixture is heated, it is the first to be evaporated and the hot water vapour will then rise in the fractionating column and condense into liquid. The boiling point of the substances that go down the column will be higher and heavier in weight.
3) I have also learnt that filter, filtrate and filtration are all different. Filter(also known as filter paper)- An apparatus used to separate insoluble substances from a mixture. Filtrate- The substances(liquid) found in the beaker (when using the filtration method) is called filtrate while the substances found on the filter paper are called residue. Filtration- The process/method to separate mixtures.

2 Questions:
1) What is the difference between filter paper and filtrate paper?
2) How long will the mixture, crude oil, be separated using the fractional distillation method?

1 Useful application:
1) Since we know that ethanol is a type of alcohol, we are able to purchase this type of alcohol by saying the correct name(ethanol) in the shop. We are also able to explain the differences between filter, filtrate and filtration to our friends who do not understand them.

National Education Lesson

I used to think that Singapore obtains their NEWater by mostly using the distillation and evaporation methods. But now I think that NEWater is obtained mostly by using the reverse osmosis method.

At first, I also used to think that reverse osmosis is not a method to separate mixtures. But now I think that when using reverse osmosis method, sea water is pre-treated to remove insoluble substances like debris and contaminants such as oil, grease and suspended solids. The sea water which has been pre-treated will then be pumped at high pressure into the partially-permeable membranes to remove all traces of soluble substances. [Soluble substances: Bacteria, chemicals, dissolved minerals, etc.]

I used to think that both reverse osmosis and desalination are the same method. But now I think that they are different as reverse osmosis is a type of method mostly used for desalination.

More Information on Separating Mixtures

3 Thoughts:
1) There is more apparatus use in fractional distillation than in distillation. The extra apparatus use in fractional distillation is called fractionating column. The substance which has the lowest boiling point will be found right at the top of the fractionating column. In addition, the substance which is the heaviest in weight will be at the bottom of the fractionating column.
2) The mixture being separated in the fractional distillation has a wide range of temperatures and there is a great difference between the temperatures. Example, there are three substances in the mixture in which their temperatures may be 30 degree Celsius, 70 degree Celsius and 120 degree Celsius. Fractional distillation is usually used to separate more than two substances from a mixture while distillation can at most separate a mixture which contains two substances.
3) By using the method called paper chromatography, a solvent (e.g. alcohol) must be used. When using the chromatography paper (long strip), a pencil mark should be drawn at around 2 or 3cm above the bottom of the strip. Ink must not be used on the strip as when it comes into contact with the solvent, the substances in it will also be separated. The pencil mark should also be above the solvent. If the pencil mark is in the solvent, the mixture will mix with the solvent and becomes another mixture. Thus, the separation of the previous mixture will not be the same and accurate. Lastly, a cock is used to cover the boiling tube so that the alcohol will not be evaporated.

2 Questions:
1) When we use the paper chromatography method, how do we know that all the substances in the mixture have been separated?
2) Why is there fractional distillation and distillation? Can the mixture which only contains two substances be separated using the fractional distillation method such that all the mixtures on Earth can be separated by the fractional distillation method and the distillation method need not be used anymore?

1 Useful application:
1) Since we know the method in using the distillation method to separate mixture, we are able to separate the substances in the mixture by ourselves if we want to use the substance which is found in the mixture. The substances in the mixture are also useful to us.

Separating Mixtures-Distillation

3 Thoughts:
1) Porcelain chips are used in boiling of the mixture in the distillation set-up so that heat will be evenly shared in the mixture and heating will be very efficient. The heat from the Bunsen burner or electric heater cause the porcelain chips to vibrate and this in turn will also cause the water to vibrate. Hence, heat will be evenly spread in the round-bottom flask.
2) Distillation set-up: The tap-water in is usually at the bottom of the condenser while the tap-water out is at the top so that it will be more efficient in condensing. The tap-water in is at the bottom end of the condenser. Thus, the hot water vapour can take time to cool down and condense into water droplets.
3) Distillation is usually used to separate different temperatures of liquid. Hence, a thermometer is used. A thermometer can be used to tell which element or compound is separated from the mixture. Example, when the thermometer reaches 100 degree Celsius, we can tell that pure water is separated from the mixture.

2 Questions:
1) If the mixture is separated by distillation method, then at the end of the heating process, will the porcelain chips still remain in the round-bottom flask?
2) When using distillation method, how do we know that a mixture has been completely separated?

1 Useful application:
By knowing more on distillation method, we are able to carry out experiments easily and know what the concept behind the method is. We are also able to answer questions on distillation with better understanding.

More on Mixtures...

3 Thoughts:
1) Evaporation is a method to separate mixtures. People usually do not heat the mixture directly so as to prevent overheating. The mixture is usually heated over a water bath.
2) Filtration is another method in separating mixtures. Filter funnel, filter paper and a beaker are used. The substance which is found in the beaker is called filtrate while the substance which was collected at the filter paper is called residue.
3) Distillation is also another method to separate mixtures. This method is usually used to separate liquid-liquid mixture of different temperatures. The apparatus being used in this method are Bunsen burner, wire gauze, tripod stand, beaker and distillation set. The mixture is heated in a distillation flask until no water is left as the water in the mixture is found in the beaker.

2 Questions:
1) How do scientists find out the methods to separate mixtures?
2) What is the difference between distillation method and evaporation method?

1 Useful application:
1) By knowing the methods in separating mixtures, we can apply it in our daily life. If we want to get salt from seawater, we can use the evaporation method.

Penny of Thoughts on Mixtures

I used to think that mixtures can be formed by combination and broken down by decomposition. But now I think that a mixture consists of two or more different substances that are mixed but does not go through any chemical reactions. Both combination and decomposition are chemical methods.

I also used to think that mixtures cannot be separated. But now I think that there are five ways to separate mixtures. The five ways are: 1) Filtration 2) Magnetic attraction 3) Distillation 4) Evaporation 5) Paper chromatography.

Mindmap on Atoms, Elements and Compounds

This is the link to my Atoms, Elements and Compounds mindmap: http://mywebspiration.com/view/500474a15b13

Workbook: Going Through Answers in Chapter 5 Worksheet

3 Thoughts:
1) I had learnt the difference between word equation and symbol equation. An example for a word equation is: Magnesium + Oxygen ---> Magnesium Oxide. But if you want to represent the equation in chemical symbol, it is like this: 2Mg + O2 ---> 2MgO.
2) Understand which are reactants and which is product. Example, Water Vapour + Carbon ---> Sugar. Water vapour and carbon are the reactants while sugar is the product.
3) Understand that element is the simplest substance and cannot be broken down further. Example, a magnesium cannot be broken into simpler substances as it is an element.

2 Questions:
1) Why did scientists change the spelling of 'sulphur' to 'sulfur'?
2) How did scientists carry out experiments to test whether which substances mix together will form another substance?

1 Useful application:
1) By knowing all of these scientific concepts, I can apply what I know to my schoolwork and examinations.