Heyo guys I am back!! Today I'll be talking about alkalis hehe. Here's some information about alkalis!
They turn the universal indicator from a shade of green to violet.
They turn the red litmus paper blue.
It's pH is above 7.
However, there is an exception of one solution called... AMMONIA!
Ammonia has a pH above 7, however it turns red litmus paper into a shade of purplish-blue and the universal indicator from green to dark green! Here's two images! (: They're for the alkali reactions!!
Isn't it cool!! Another experiment we did shown the colour change of the acid when we continuously added drops of sodium hydroxide to it. Why does this happen? This is because sodium hydroxide is an alkali, so it causes the acid to have a change in pH and become more of an alkali as more drops are added! Here's the image of the different colours!
Okay! That's all folks! Hope you've learnt something! (:
Ello everyone! I'm back again, this time about acids that can BURN you. Here is a short introduction on acids!
Acids have a pH of less than 7. (7 is NEUTRAL)
Acids are substances that produce H+ ions in water.
Sour Taste (Please don't try don't you will burn your tongue, probably)
Dissolves in water to form solutions that conduct electricity
How do we test if a solution/liquid is a acid. We can't possibly drink it, right? Here's one experiment we did, and it can help us determine which solution is an acid. Here are the following steps:
Firstly, take some blue and red litmus paper and place both pieces on a white tile.
Next, drip a drop of the solution onto each piece of paper.
Fill a test tube with the universal indicator solution.
Drip a drop of the solution into the test tube.
Observe and record your observations down.
Basically, what you should get is the following results:
The blue litmus paper turns red, and the red litmus paper remains red.
The universal indicator solution, which was green in our case, turned red.
Here are some videos for you to see the changes!
We did two other experiments on acids, but we did not video them or take any pictures because the reactions were rather fast. Let me describe in words the experiments we did!
In the other two experiments, we basically mixed acid with carbonate and metal respectively by themselves, which means the second experiment was acid plus carbonate, while the third experiment was acid plus metal. Basically, this entire experiment time was to see what happens when acids react with other substances/materials.
In general, we learnt 3 equations after that lesson. They are general equations which will help you in your paper (; *hints*
Metal + Acid --> Salt + Hydrogen
Base/Alkali + Acid --> Salt + Water
Carbonate + Acid --> Salt + Water + Carbon Dioxide
Here's more about Chemical Changes! There are 3 different types of reactions (for Chemical Changes)
Combination
Two or more elements react to form a new compound
Decomposition
Substances breaking down into 2 or more substances
Combustion
Involves the burning of a substance in the presence of oxygen to form new compounds
The result of combustion (reaction) is oxygen and carbon dioxide
Here's a picture to show you an example of decomposition! (:
I can't remember what really happened, but basically we heated this green powder up and it changed colour to black :D This is the only photo I have from the experiments for Chemical Changes :( Hope this short post was useful, everyone good luck for TAs on 16th May!! (:
