S3 - Chemistry Test Flashcards
In ENDOTHERMIC reactions, the REACTANTS have less energy than the product.
True or False
True
Give an example of a PHYSICAL and CHEMICAL change.
Physical - Ice melting / Dissolving / Water boiling
Chemical - Burning / Baking / Growing
Define what is meant by EXOTHERMIC and ENDOTHERMIC.
Exothermic - Energy is released
Endothermic - Energy is taken in
What is EFFERVESCENCE?
When gas or bubbles are produced.
What is it called when a colour change takes place?
Thermal Decomposition
The substance produced in a chemical reaction is called…
The Product
How can you calculate the rate of a reaction?
By dividing the change in amount of product by the time taken.
Name the 4 indicators of a chemical reaction.
- Thermal Decomposition (colour change)
- Effervescence (bubbles or gas)
- Precipitation (solid formed)
- Energy Change
What are ‘The reactants’?
The chemicals used for a chemical reaction to take place.
Explain how concentration can speed up the rate of reaction.
The higher the concentration, the more particles there are moving around which then allows for more collisions to take place and therefore speedup the rate of reaction.
How does particle size affect the rate of reaction?
Decreasing the particle size increases the surface area allowing for the reaction to take place quicker.
Name the 5 factors which speed up the rate of reaction.
- Concentration
- Catalysts
- Temperature
- Particle Size
- Agitation
What is it called when liquids form a solid?
Precipitation
Why do the products in an exothermic reaction release heat energy?
The reactants hold too much energy
Why do reactants with a higher temperature react faster than ones with a lower?
Particles move faster at higher temperatures
What is the name of group 1 on the periodic table?
Alkali Metals
What is the name of group 7 in the periodic table?
Halogens
What is name of group 8 in the periodic table?
Noble Gases
What are the transitions metals?
A large group of common metals found in the middle of the periodic table.
What are diatomic elements?
2 atoms joined together
What are the diatomic elements?
Hydrogen / Nitrogen / Oxygen / Chlorine / Fluorine / Bromine / Iodine
What is the valency of an element?
The amount of bonds the atom can make.
From what group does the valency start to decrease back to 0?
Group 5
As Transition metals can change their valency how do we know which valency to use when working out formulas?
The Roman numerals written after the first element ( transition metal )
How do we work out the valency for the ‘Rule Breakers’ ?
The prefix written before the element
What are the prefixes used with the ‘Rule Breakers’ ?
Mono - 1
Di - 2
Tri - 3
Tetra - 4
Penta - 5
When do we not use the cross over method for working out compounds ?
With the ‘ Rule Breakers’
How do we write out a word equation?
Reactants ~~~~> Products
Eg. Copper + Oxygen ~~~~> Copper(ll) oxide
What is a rule we must remember when writing word equations?
It must all fit in the same line.
