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
What name do we give to reactions that release heat?
Exothermic
What name do we give to reactions that take in heat?
Endothermic
What is the “independent variable” ?
The thing you have decided to change in an experiment
What is the “dependent variable” ?
The thing that you are measured or observing
What are the 2 main dependent variables used to calculate Rate of reaction
Volume of gas
Mass loss
What dependant variables ( other than volume of gas and mass loss) could be measured as a reaction progresses?
concentration
pH
What is apparatus for measuring mass as dependent variable in order to calculate Rate of reaction?
What is apparatus for measuring gas volumes in order to claculate Rate of Reaction
Why are catalysts used in industry?
Name 4 ways to increase the rate of reaction
Increasing concentration of solution Increasing temperature
Adding a catalyst
Decreasing particle size
What is meant by “collision theory”?
The idea that particles must collide in order to react
How does decreasing particle size of a solid increase reaction rate?
Collision take place on the surface and the surface area is increased by decreasing particle size
How does increasing concentration increase reaction rate?
More particles in given area means that particles will collide more often.
What is meant by temperature?
How does increasing temperature increase reaction rate?
The particles are moving faster and collide more often and with more energy.
