Science : CHAPTER 5 - Acids & Alkalis (II)

Dear students of 7 Aqua & Aer,

** Do read through everything before you start to do anything. **

Please do a revision by reading up on the link Module 5 – Acids & alkalis again.

Once you have finished reading, I require every one of you to write a report by writing some short notes as a report on these few questions that I will list below. Please be advised that you are allowed to use the search engines on the internet to help you write your report. However, do read through the facts and only choose the relevant ones.

Guiding questions:

1) The characteristics of acids.

2) The characteristics of alkalis

3) Neutral substances

4) Everyday uses of acids and alkalis (make sure you state appropriate examples)

5) The common hazard symbols which are associated with acids and alkalis

You are to hand in the report at the end of the class.

For those of you who are able to finish up early, you might want to try out this activity of The Virtual Kitchen.Good luck and have fun – in Science! Please remember to hand in your report. I’ll see you tomorrow. ^_^

Chapter 5 : Acids & Alkalis - Indicators

Dear students,

Today we will be learning about INDICATORS. What are indicators actually? If you search from the dictionary, indicators means "to point out" or "to specify something". Those are very general definitons of what the word indicator is. However, in Science, when you mention an indicator, it gives a whole different meaning to it.

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Indicators

There is a device called a pH meter which you can dip into a liquid and which will measure its pH. However, it is easier to use an indicator.

An indicator is a chemical that changes colour. Indicators are liquids, but they can be soaked into a type of paper similar to blotting-paper to form strips of indicator paper.

Just dip the indicator paper into the unknown liquid and it will change colour to show the pH.

The simplest indicator is Litmus (from the Litmus plant). It goes red in acids, blue in alkalis.

pH = less than 7	pH = more than 7

Universal indicator is a better indicator than litmus because it can show a greater range of colours. The chart below shows the approximate colour that universal indicator goes when put into liquids of different pH values.

pH = 3 or less	pH = 4 or 5	pH = 6	pH = 7 (neutral)	pH = 8 or 9	pH = 10 or more

Universal indicator is available as a liquid or soaked into absorbing paper. It is often used to work out the pH of soil samples to see which plants can be grown in a certain patch of ground.

There are other indicators, for example, methyl orange (which changes colour from colourless to orange at pH of about 3). They all have different pH values where they change colour, and each has its own uses.

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If you want to find out more on indicators, click on this website What are some natural acid/base indicators?

Remember, if you have fun learning about Science, you will learn about Science!

Science: CHAPTER 5 - Acids & Alkalis (I)

Dear students of 7 Aer, Aqua & Terra,

Please google up "Acids and alkalis Year 7" and find out more on what exactly are they. Or you can go to Module 5 -Acids and alkalis.

Once you have done that, go to the link under "For My Students" for Alien Juice Bar. Try every component under that, only then proceed to The pH factor.

As you are playing those educational games, please be reminded that you are to read all the pop-ups that give you facts from time to time. From there you can gather on the whole on what acids and alkalis are like, what are their characteristics and identify certain examples.

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For revision, please try out Acids & Alkalis - Matching game and also read up on Acids & Alkalis - terms you need to know.

My wedding...

For those of you who knew about it and were also there for my big day, it was on the 10th November 2007. It was a church wedding, with all the frills and flowers as usually is seen in most church weddings. Some friends commented that it was so much like a fairytale wedding. ^_^ I myself wasn't sure because of the stress....which got me so preoccupied and single-minded focus on just surviving the day that I did not notice much.

However, there was one thing that I would like to share. =) My husband (at that time fiance.. =p) ....he gave me such a nice, romantic surprise till I dunno what to do but cry on the spot! It was so touching and really...such a BIG SURPRISE!! Honestly, I didn't expect that from him since he's quite a shy guy, which likes to attract the least attention from people. HAHA.... So it really hit me big time. And I was teased afterwards.... "How come you cried even before he started singing?" Haha..... How couldn't I?

That's why I love him so much!! He is always trying to give me little touching surprises everytime when I totally do not expect it coming. ^_^