Chemical reactions Flashcards
(27 cards)
What colour would a strong alkali turn using universal indicator
Purple
What is the difference between a chemical and physical change
Chemical changes are not reversible but physical changes are
What is an acid
A substance with a pH lower than 7
Give an example of an acid with a pH of 1-2
HCL/ stomach acid
What hazard might an acid pose
It might be corrosive
What is an indicator
A dye that changes colour depending what pH a liquid is
What is an alkali
A water soluble base
What is a base
A substance with a pH over 7
What is a neutral substance
Water
What hazard might an alkali pose
It might be irritant
Is ice melting a chemical change? Why?
No, you can freeze it back into its original shape
Is food being burnt a chemical change? Why?
Yes, the particles have changed and cannot be restored.
What pH is lemon juice
2.4
What colour would litmus turn a strong alkali
Blue
Is litmus or universal more effective
Universal
What colour would a weak acid turn in universal indicator
Orange or yellow
What does the pH scale measure
How acidic or alkaine a substance is
What is sodium oxide + nitric acid
Sodium nitrate+ water
What is copper hydroxide + sulphuric acid
Copper sulphate+ water
What is neutralisation
An acid and alkali mixing to a substance with a pH of 7
How do you neutralise a base
With acid
What is also produced with water in neutralisation
Salt
What makes copper nitrate+ water
Copper oxide+ nitric acid
What makes magnesium citrate
Citric acid+ magnesium hydroxide
