Class VIII Semester 2

Basic competence: Communicating the data collecting about chemicals used in industry, agriculture, and health Indicators: Listing chemicals used in industry and agriculture based on the package Explaining the use of chemicals in industry and agriculture based on the available information

Sub indicators/objectives Describe the composition of paint and sulphuric acid Able to group paint according to its function Able to know the danger of paint and sulphate acid

Have you ever observed the building around you carefully? What things can you see ? Have you ever observed the fence in your house? Do you find corrosive things there? How about your car? What is the function of the paint of your car?

Paint is a suspension of a solid material dispersed in a liquid The suspended solid is called pigment The function of pigment are to protect the surface, for decorative need, and as a thin coating which is either transparent or not.

The surface of thing painted is protected from the rust process, insect attacks, and fungi. A good paint is not easily peeled off the surface painted and resistant to light, heat, atmospheric change and seasons.

A good quality, paint has to have the following ingredients: Pigment The color material is compound existing naturally or made synthetically Dispersion medium.The substance function to disperse the pigment in a paint. It is volatile and non corrosive. A compound is turpentine oil and tung or oil Chinese wood oil.

DriersThere are metal compounds (0,5 – 2 %) which carry oxygen and help the medium drying by medium oxidation ThinnersThese help the formation of slippery surface in painting process to form similar and uniform paint layer. It contains benzene and naphtalene. They are easy to vapor and burn. Fillers China clay, talc, BaSO4, etc added to the pigment to improve its resistance

Paint pigments are usually classified based on the colors. There are some example of each pigment group: The function of Paint Protected the surface from the rust process, insect attacks and fungi

Pigment Group Explanation White Pigment:  White lead  Sublimated white Lead  China white Yellow or Orange Pigment:  Mishicot (yellow)  Cadmium (yellow)  Tungstat acid  Chromate zinc Red Pigment :  Chrome red  Iron oxides  Vermilion  Mercury oxide  Red lead Green Pigment :  Chrome green  Berlin Green  Giugnet Good pigment, darkened by H2S Whiter than white lead Not as white as white lead and not darkened by H2S For ceramics Reddish glow Boiling PbCrO4 and base Poisonous Oil paint Poisonous

Important to note, that pigments are compounds composed of poisonous metals. Therefore, should be careful and do not use container whose inside part is decorated with paint to store food, vegetables, medicine, etc. Conclusion  The color of paint is caused by a pigment  The function of the paint are to protected the surface from the rust process, insect attacks, and fungi  A good paint is not easily peeled off the surface painted and resistant to light, heat, atmospheric changes and seasons

Be careful and do not use container whose inside part is decorated with paint to store food, vegetable, medicine, etc For your home work, find the ingredients of paint and classify them according to which of them use water or oil as their solvent THANK YOU AND BYE

Basic competence: Communicating the data collecting about chemicals used in industry, agriculture, and health Indicators: LListing chemicals used in industry and agriculture based on the package EExplaining the use of chemicals in industry and agriculture based on the available information Sub indicator/objective: Estimating the dangerous of sulphuric acid

There are two processes to make sulfate acid in a great amount: 1.Lead Room Process in this process big room whose walls are coated with lead (Pb) are used. The concentration of sulphate acid produced is about 62,5% and the catalyst in this process is NO 2. Contact Process is not too different from lead room process only that the catalyst used is Platinum (Pt) This process was seen as a less advantageous one because of some reasons: a. the little need of high concentrated sulphate acid b. the expensive price of Pt c. the little knowledge of catalyst d. the slow development of chemistry technology

1.Pour the sulphuric acid to the beaker glass 2.Inhale the air around the beaker glass (Do it carefully) 3.What do you feel? 4.Take a drop of sulphuric acid and drop it on a piece of paper 5.What will be happen? 6.Immerse the stone into beaker glass 7.What will be happen?