E block core questions Flashcards
C6.1 Physical and chemical change
C7.3.6 Preparing insoluble salts
What is a chemical reaction?
A process in which new chemicals are made from old
What are the three main signs of a chemical reaction?
Bubbles, temperature change, colour change
What is a chemical change?
An irreversible change in the arrangement of atoms
What is a physical change?
A reversible change in the arrangement of particles
Name six types of physical change
Melting, boiling, evaporation, condensation, sublimation, dissolving
What does the state symbol (s) mean?
Solid
What does the state symbol (l) mean?
Liquid
What does the state symbol (g) mean?
Gas
What does the state symbol (aq) mean?
Aqueous/dissolved in water
What is a solvent?
A liquid in which something dissolves
What is a solute?
A chemical which dissolves in a liquid
What is a solution?
A mixture of a solvent and a solute
What does soluble mean?
Will dissolve
What does insoluble mean?
Will not dissolve
C6.2.5 Explaining rates (E)
C6.2.4 Factors affecting the rate of reaction
What must particles do in order to have a chance to react?
Collide (with sufficient energy and in the correct orientation)
What is rate of reaction?
How quickly a reaction takes place
Units and symbols for rate?
Cubic centimetres per second (cm3/s) & grams per second (g/s)
What is rate of reaction?
How quickly a reaction takes place
Units and symbols for rate?
Cubic centimetres per second (cm3/s) & grams per second (g/s)
How can you monitor rate of reaction?
How quickly a product is formed or a reactant is used
How can you measure how quickly a product is formed?
Volume of gas per second using a gas syringe, change in mass
How can you measure how quickly a reactant is used?
Change in mass
How can you monitor changes in concentration to measure rate?
Changes in colour or turbidity (disappearing cross)
How can you calculate relative rate from time taken?
relative rate = 1/time taken
On a graph of concentration/mass/volume of gas against time, what is represented by the gradient?
rate of reaction
What are the 5 factors that can alter the rate of reaction?
Temperature, surface area, pressure (gases), concentration and catalyst
What is activation energy?
The minimum energy with which particles must collide in order to react
C6.2.3 Practical Measuring disappeareance of reactants
C6.2.7 Practical: the effect of particle size on reaction rate
Unit and symbol for mass?
Kilogram/kg (gram/g)
Unit and symbol for volume?
Cubic metres/m3 (cubic centimetres/cm3) (cubic decimetre/dm3)
What is rate of reaction?
How quickly a reaction takes place
Units and symbols for rate?
Cubic centimetres per second (cm3/s) & grams per second (g/s)
How can you monitor rate of reaction?
How quickly a product is formed or a reactant is used
How can you measure how quickly a reactant is used?
Change in mass
On a graph of concentration/mass/volume of gas against time, what is represented by the gradient?
rate of reaction
What are the 5 factors that can alter the rate of reaction?
Temperature, surface area, pressure (gases), concentration and catalyst
How does temperature affect rate of reaction?
Increasing temperature increases rate of reaction
What needs to happen to collisions between particles to increase rate?
Increased frequency and/or increased energy
What effect does breaking solid matter into smaller bits have on surface area?
Increases surface area to volume ratio.
How does surface area affect rate of reaction?
Increasing surface area increases rate of reaction
Why does a larger surface area increase rate of reaction?
More particles at the surface and available for collisions
