Chemistry yr 7 Flashcards
What would a graph documenting the increase of temperature of an impure substance look like?
Where there is a vertical line at some point in the graph to show stabilizing temperature before state change (with a pure substance), there is a curved line instead to due to the mixture of elements within
What is the difference between evaporation and boiling?
- Boiling occurs at a fixed temperature whereas evaporation does not
- Boiling takes place throughout the liquid whereas evaporation only takes place at the surface
- In boiling, thermal energy is supplied by an energy source whereas evaporation’s thermal energy is supplied by its surroundings
What is diffusion?
Diffusion is the process by which particles of one substance spread out through the particles of another substance from an area of high concentration to an area of low concentration
How does diffusion differ with different elements?
Gasses have lower particle density, which is why diffusion is faster within gasses than the other states of matter
Why do balloons get bigger as you blow them up?
The gas particles exert a force on the balloon’s rubber, causing it to expand
What is gas pressure?
The force per unit area of the container the gas is in
(per square metre)
Which gas withstands cold temperature?
Nitrogen
How does increasing temperature increase gas pressure?
- increasing temperature —>
- increases particle energy –>
- increases particle speed of movement —>
- increases particle collisions —>
- increases gas pressure
What is an element?
a substance made up of one kind of atom
What is a compound?
A pure substance made up of two or more elements chemically bonded together
What is a mixture?
2 or more elements that are not chemically bonded
How do you name metal + non-metal compounds?
Metal + non metal ending ide
How do you name metal + non-metal + oxygen compounds?
Metal + non metal ending ate
Saturated definition
A solvent that can’t dissolve any more solute
What is fuel?
A material that burns to transfer energy by heating
What is combustion?
Burning
Combustion formula
fuel + oxygen –> carbon dioxide + water
Conservation of Mass formula
mass of reactants = mass of products
atoms cannot be created or destroyed
What is decomposition?
the breaking down of a substance
What is thermal decomposition?
The process of breaking down a substance using heat
What does a metal carbonate break down into?
metal carbonate —> metal oxide + carbon dioxide
What is a reversible reaction?
A reaction in which the products formed can either decompose or react to give the reactants back again
What happens to the particles of the solute when dissolved in solvent?
The particles of the solvent surround those of the solute
What is distillation?
A method used to separate a soluble solid from a liquid
What is chromatography?
Chromatography is a separation technique used to separate mixtures of soluble substances
can be used for both coloured substances (like pen ink) and non coloured substances (like drugs)
liquid —> gas
at the surface of seawater
boiling
gas —> liquid
condensation
molecule
2 or more atoms chemically bonded together
