That’s right, limestone – you’ve probably heard of it, and you need to know all about it for the C1 exam. Ready to learn all about limestone, its uses, reactions, and the super-special awesome limestone cycle? Well, here we go…
Now, you might be thinking that all of the ion tests knowledge has been covered in other articles – and you’d be right. But really, who wouldn’t want a handy compilation article with everything in? Testing for both positive and negative ions, including halide, sulfate and nitrate ions, and looking at flame tests and other positive ion tests. More »
You may wonder why this article is here, given we’ve done an article on hard & soft water before – well, it’s because there’s some other stuff that you need to know about it, like how it is treated, detailed descriptions of removing hardness, and issues with hard and soft water – all in this article.
Sometimes in conjunction with flame tests, you can use sodium hydroxide to test for the presence of positive metal ions. This works because most ions with a +2 or +3 charge are insoluble in water. Therefore, when sodium hydroxide is added to a solution containing them, a hydroxide precipitate forms, containing the insoluble metal.
We can identify positive ions in different compounds or solutions by using a flame test. In a flame test, the flame will change colour depending on the ions present in the substance you’re testing.
Below is a table of different positive ions and their respective colour:
One potential issue with flame tests is that if there is more than one ion present, one colour could mask another. This is why you should also test with sodium hydroxide.
The formula above is your friend when it comes to titration (or ‘concentration’) calculations. By simply slotting in the numbers you’re (usually) given in the question, you can come up with an easy answer, and an easy few marks.
Now we get to probably one of the most interesting parts of the AQA C3 course – the organic chemistry. Not excited already? You get to understand what formula alcohol has, what is actually in vinegar and how they actually make perfumes. Doesn’t sound interesting to you? Well, unfortunately, that’s just too bad, because you need to know it for the AQA C3 exam. Ready (and hopefully excited)? Then let’s go for it…
We’re going to outline two aspects of the periodic table: its history and its current structure and layout – both things you could need to know in an exam! It’s a reasonably simple topic, as long as you’re able to remember a few names and a couple of facts. So without further ado…
One of the most basic fuels (or, at least, mixture of fuels) around – and for the C1 exam, you have to know all about it. What it actually is, different fractions, and how to separate them – this and more is stuff you need to know. So, let’s guess what we’re going to cover here… that’s right, everything about crude oil that you need for the C1 exam. Ready? Here we go…