Q.1. What is crystallite and colloidal particle ? Crystallite particle : the particle which can passes through the semi permeable membrane are known as crystallite particle. The size of crystallite particle is less than that of 10 cm. Eg : sugar, urea, salt solution. Colloidal particle : the particle which cannot pass through the semipermeable membrane are known as colloidal particle. The size of colloidal particle is between 10 – 10 cm. Eg : starch, protein, albumin, gelatin. Q.2. What is suspension ? Suspension : the particle whose size is more than 10 cm and which make heterogeneous solution with solvent is known as suspension. Eg : muddy water, barium sulphate solution etc. Q.3. what is true solution ? True solution : the solution in which the size of the particle is less than 10 cm, 10m or 1nm that solution is known as true solution. Eg : aqueous solution of sugar, salt. Q.4. what is collo...
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PVC : preparation, properties and uses.
PVC (POLYVINYL CHLORIDE) Its monomer unit is vinyl chloride. PREPARATION Vinyl chloride is prepared by the treatment of acetylene and HCl in presence of HgCl2 at 100 -200°C temperature. A mixture of liquid vinyl chloride and per sulphate catalyst such as sodium per sulphate (Na2S2O8) and H2O are taken in a reactor and shaken vigrously when tiny globules like latex is produce. It is then introduce in a autoclane at 40 - 45 °C temperature. The reaction is get completed at about 72 hours. The polymer particles are then recovered by coagulation by an acid solution. It is then filtered and dried and moulded according to properties desired by using plasticiser, lubricants filter etc. PROPERTIES OF PVC Polyvinyl chloride are chemically inert and does not react with acid and ...
Industrial production of ethyl alcohol by fermentation.
1. Industrial production of ethyl alcohol by fermentation The raw material used for the large scale production of ethyl alcohol by the process of fermentation Molasses and starch. 1.1. FROM MOLASSES In our country molasses is the chief raw material for the production of ethyl alcohol. Molasses contains about 30% sucrose and about 32% invert sugar . As strong sugar concentration is not suitable for fermentation by yeast, it is diluted with water to a 10% sugar solution called " mash ". It is then transferred to a large steel tank called fermenter and made slightly acidic (PH 4.0 to 5.0) by adding sulphuric acid . Acid prevents the growth of unwanted bacteria and promotes vigorous growth of yeast cells beneficial for alcoholic fermentation. Required amount of ammonium sulphate and ammonium phosp...
Cosmetics and perfumes (chemistry part-2)
6. SUNTAN LOTION :- Sunlight possesses both beneficial and harmful effects on the skin . Exposure to moderate sunlight increases blood circulation , produces vitamin D in the body,kills germs and causes thickening of the skin to prevent sunburn .these are the main beneficial effects. However, long exposure may damage the skin producing erythema ( reddening ), painful burn,blister,swelling of the skin and something skin cancer . Some natural protection against sunburn is obtained by thickening of the skin due to increased rate of cell formation at the epidermis and also increased melanin content of the epidermis. The purpose of suntan lotion is to minimise the harmful effects of the sunlight and to assist tanning of the skin . The suntan lotions are chemicals which act as sunscreen to absorb at l...
what is colloidal particle and size ?
Q. what is colloidal particle and size ? Colloidal particle : the particle which cannot pass through the semipermeable membrane are known as colloidal particle. The size of colloidal particle is between 10 -7 – 10 -5 cm. Eg : starch, protein, albumin, gelatin.
Cosmetics and perfumes (part-1)
INTRODUCTION many types of raw materials can be used in the formulation of cosmetics. The choice of the raw materials involves the consideration of the following factors,viz. aesthetic value, colour ,availability, skin compatibility, environmental compatibility, smell acceptability ,stability and cost . The stability refers to Physical,chemical and microbial stability. Cosmetic raw materials are mixtures of wide variety of individual components. Some cosmetics and perfumes are given below:-- 1. FACE POWDER:- The function of the face powder is to mask any minor defect on the skin and supress oily patches so that the face appears to be smooth, beautiful and attractive. the modern face powder is a mechanical mixture of several constitutents each of which confers its own properties to the final blend. The face powder should possess desired covering powder, adhesion property, slip,a...
Definition Of Significant Figure And Rounding Off Examples.
Q.1. What is SIGNIFICANT FIGURE ? SIGNIFICANT FIGURE the significant figure in a numerical expression is defined as these digit whose value are known along with additional digit whole value is uncertain. Eg : 24.82 cm having 3 certain digits are 2, 4, 8 and one doubtful digit is 2. Therefore, this reading has 4 significant figure. * Rules for determining the number of significant figure : 1. Except zero(0) all the digit 1 to 9 are significant. Example : 4.25 number has 3 significant figure. 71. 435 number has 5 significant figure. 2. All digits include zero are significant if zero appears in between non-zero digit. Example : 40.05 has 4 significant figure. 3. Zero to the left of the first non- zero digit in a number is not significant. It indicates only decimal point. Example : 0.4 28 has 3 significant figure. 0.054 has 2 significant figure. 4. ...