ST.1 Chemical Changes and Rates N5 (CCS) Flashcards
What is a physical change?
A change from one state to another without a change in chemical composition
What is a chemical change?
A change that is usually non reversible and produces a new substance
List some signs of a chemical change
pH change, temperature change, colour change, precipitation, effervescence
List some signs of a physical change
State change, no new substances formed
What is meant by precipitation?
An insoluble solid is formed
What is meant by effervescence?
Gas is given off
What is the rate of a reaction?
How fast or slow a reaction is
What are some examples of a slow reaction?
Plant growth, rusting, photosynthesis, coal formation
What are some examples of a fast reaction?
ALKALI METAL + WATER, burning, fireworks
Name some methods we can use to measure the rate of a reaction
Downwards displacement of water, mass change and gas syringe
Name the equipment used in downwards displacement of water
Conical flask, delivery tube, water trough and a boiling/test tube
Name the equipment used in a mass change experiment
Cotton wool, conical flask, electronic balance
Name the equipment used in a gas syringe experiment
Conical flask, gas syringe
What equation do you use to calculate the average rate of reaction?
change in quantity/change in time
What is a catalyst?
A catalyst is a substance that speeds up the rate of a reaction and is unchanged throughout
