1.1 Reactions and Reaction Rates Flashcards
What is an element?
A substance containing only 1 type of atom
What is a compound?
2 or more elements chemically combined
What is a reactant?
A substance that takes part in a chemical reaction
What is a product?
A substance produced in a chemical reaction
What is ALWAYS produced in a chemical reaction?
A new substance
What are the 5 signs of a chemical reaction?
Gas given off
Colour change
Smell
Energy change (temperature, light)
Solid formed
How can we detect energy changes in a reaction?
Using a thermometer to detect change in temp
Feeling heat given off by a reaction
Hearing sound energy
Seeing Light energy
How do reactions occur?
Particles of reactants collide.
( collision theory)
Why do reactions stop?
Particles of one of the reactants “run out”
What is the “limiting reactant”?
The reactant whose particles are all used up first
What is the “excess reactant” ?
The reactant that still has particles present when the reaction stops.
What is qualitative data?
Data based on judgement using the senses
What is quantitative data?
Data based on measurements of quantity and / or time.
What is meant by “independant” variable?
The thing we choose to change in an investigation
What is meant by “ dependant” variable
The thing in a reaction that we measure as a result of the reaction
- volume of gas produced
- mass of reactants produced
