Ms November Exam Flashcards
Work through these - it will help you in the exam
This is the variable that you change each time you do the experiment
the independent variable
The dependent variable is
The variable that you measure each time you do the experiment.
The variables you must keep the same each time you do an experiment are called
the control variables
To gain more reliable results you
repeat your experiment
To make your experiment more accurate
you need to improve your method, perhaps by improving the equipment you use, a measuring cylinder would more accurately measure volume than a beaker for example.
To test for oxygen
Use a glowing splint, when put in oxygen, it will relight
metal + oxygen
͢ metal oxide
magnesium + oxygen
magnesium oxide
What is the boiling point of pure water?
100 degrees C
What is the melting point of water?
zero degrees C
seawater is a mixture, how could you get the salt out?
evaporate
chemical test for water
anhydrous copper(II) sulfate goes from white to blue
What is chromatorgraphy used for?
Paper chromatography is a method for separating dissolved substances from one another. It is often used when the dissolved substances are coloured, such as inks, food colourings and plant dyes
An element
A pure substance which cannot be broken down into anything simpler
A compound
Two or more elements which are chemically bonded together
A mixture
Two or more substances which can be separated.
A molecule
Two or more atoms joined together
Write a word equation for combustion
fuel + oxygen͢ carbon dioxide + water. ( A fuel is often a hydrocarbon like methane for example)
How can you increase solubility?
crush the solute,
stir
Increase the heat
How can you get a solute back out of solution?
evaporate - for example copper sulfate solution will leave copper sulfate crystals when left to evaporate
What does OXIDATION mean?
Oxygen has been gained
What does REDUCTION mean?
Oxygen has been lost
What is themal decomposition?
A reaction in which a substance is broken down into at least two other substances by heat.
This could happen when potassium permanganate is heated
