ACTIVITIES /PROJECTS ON ACIDS AND BASES

PROJECT 1—WITH ANTACIDS Aim—To find the action of antacids on Acid   The class was divided into three groups Group1 and 2 had to perform the experiment separately and compare their findings. Group 3 had to make a ppt presentation of the work done and share their internet findings on the project with the rest of the class Materials needed---a set of pestle and mortar,two 100ml beakers, a small measuring cylinder,a few antacid tables, PH paper,dilute hydrochloric acid,a glass rod for stirring Procedure: a beaker was filled with 10ml of water.  the pH of the water was tested and recorded  

one antacid tablet was crushed and place into the beaker with the water.   2 drops of phenolphthalein was added and the color recorded.   the pH of this solution was recorded   The 2nd beaker was then filledwith 10ml of the acid. the pH of the acid was recorded Next 7 antacid tablets were crushed one by one and place into the beaker with the acid.  After the r eaction stopped, the pH of this solution was tested after each addition. The findings were recorded in the following observation table-----    

OBSERVATION TABLE

PHOTOGALLERY

Our internet research HCl ,produced by the cells lining the stomach,helps in the production of the enzyme pepsin which helps to break the peptide bonds and trigger the digestion of proteins.It also helps prevent the growth of micro-organisms The secretion of Sodium bicarbonate helps to neutralise excess acid and maintain the pH level HCl +NaHCO3= NaCl + H2CO3

Extension Activity: Design an experiment to test and compare the effectiveness of different over the counter antacid brands. Include antacids in different forms such as liquid, capsule, and tablet.  

Materials—three 100ml glass beakers,potato,knife,sketch pen dilute acetic acid,sodium bicarbonate solution Procedure - Day One The glass beakers were labelled as 1 Sample 2 Acid 3 basic 1-2 slices of potato was added to each beaker Enough acid and the base solution was added to the beakers 2 and 3 so as to cover the slices and the appearance of the potato slices I was immediately noted following treatment. the apple slices were set aside for a day. ACTIVITTY -2 To find the effect of acids and bases on the rate of browning of potatoes

Procedure and Data - Day Two the potato slices were observed and observations recorded such as extent of browning (e.g., white,lightly brown, very brown, pink), texture of the apple (dry? slimy?), and any other characteristics (smooth, wrinkled, odor, etc.)

Results and conclusions Thus it can be concluded that acid reduces the rate of browning. This explains why chefs sprinkle lemon juice on salad vegetables

Our internet research The browning is due to the oxidation of the enzyme tyrosinase which catalyses the formation of the pigment melanin. Some other methods which may be used to prevent the browning are --------- By heating By reducing the amount of available oxygen By adding preservatives

photogallery The potato experiment

Extension activity The process can be repeated with apples,banana and peaches and the rate of browning compared

INDICATORS MAGIC WITH PHENOLPHTHALEIN In a beaker, pour about 100 ml of water and 3 drops of phenolphthalein. The phenolphthalein is an indicator which usually is colorless. You will obtain a colorless solution, just like water

With a dropper, add some drops of ammonia. You will see the solution suddenly become reddish purple.

Now, to the red-purple fluid you obtained, add some drops of vinegar. What it happens? The liquid becomes colorless again!!!

SOME ACTIVITIES ACTIVITY 1---- MAGIC WRITING ACTIVITY 2----BLOWING AIR INTO MAGIC SOLUTION ACTIVITY 3---- THE THREE MAGIC BEAKERS INTERACTION OBSERVATION CONCLUSION

PROJECT 3—MAKING NATURAL INDICATORS RED CABBAGE JUICE  Red cabbage. Cut the cabbage into  slices and put them in a pot. Add water enough to cover  the slices and boil for half an hour. Pour the juice  in a low container

Red cabbage juice mixed with  baking soda (left) and with vinegar (right).  On the top, a drop of unmixed juice. Chemical Colour Change Acid/Base Tap Water No noticeable colour change pH neutral Baking Soda Blue to blue-green Base Vinegar Red to purplish-red Acid Tartaric Acid Bright red Acid Laundry Powder Yellow-green Base Lemonade Purple Acid Lemon Juice BrightRed Acid

Preparing red cabbage pH papers. Soaking cards  with red cabbage juice Drying the cards. Red cabbage paper  in solution of lemon juice. Red cabbage card in a  saturated solution of baking soda

FLOWER INDICATORS what You Need: 3 or more different kinds of red, pink, orange, blue, or purple flowers White vinegar 3 or more spoons (you'll need one spoon per kind of flower) 5 or more clear plastic cups Baking soda

STEPS label one plastic cup with the word "acid" and another with the word “base". Pour about half a cup of white vinegar into the “acid” cup. Mix about half a cup of water with a few teaspoons of baking soda in the “base” cup. choose one kind of flower and crush its petals into a pulp . Divide the crushed petals into the other three plastic cups and add a drop or two of water in each one. add a few drops of acid to one cup and a few drops of base to another. Compare the contents of these two cups with the contents of the third, which contains just the flower pulp Repeat steps 2-4 with the other kinds of flowers you gathered. Wash the plastic cups thoroughly

OUR INDICATOR LAB Turmeric indicator Beetroot indicator

t thank you