C1 Flashcards
Which state something is at a given temperature depends on…
how strong the forces of attraction are between the particles of the material
What is a physical change?
When substances change from one state to another- easy to reverse
What is a chemical change?
When bonds between atoms break and the atoms change places
In solids, how strong are the fores of attraction between particles and what is the effect on the structure?
There are strong forces between particles, which holds them close together in fixed positions to form a regular latice. The volume and shape is constant.
In liquids, how strong are the fores of attraction between particles and what is the effect on the structure?
There are weaker forces than in solid between particles, which allows them to move past each other, but tend to stay close together. The volume is constant but the shape is changeable.
In gases, how strong are the fores of attraction between particles and what is the effect on the structure?
There are no forces between particles, which means they are free to move and are far apart. The volume and shape are both changeable
What are the flaws to the particle theory?
- It doesn’t show different shapes / types of particles
- It doesn’t show the forces between particles, therefore therefore there is no way of telling how strong they are
What are displacement reactions?
When in a reaction, a more reactive element displaces less reactive element
Why is bond breaking an endothermic process?
Because bonds require energy to be broken
Why is bond forming an exothermic process?
Because energy is released when bonds are formed
What is the formula to work out the overall energy change in a reaction?
Overall energy change = Energy required to break bonds - Energy released by forming bonds
Describe what phase 1’s atmosphere was like and why
It was mostly CO2, due to the vast amount of volcanoes. There was also a fair bit of nitrogen and water vapour
Describe what phase 2’s atmosphere was like and why
The Earth cooled, causing the water vapour to condense and form the ocean. This then meant the masses of CO2 was also significantly reduced, as lots dissolved in the oceans
Describe what phase 3’s atmosphere was like and why
The introduction and development of plant life meant that CO2 levels dropped further, as well O2 levels began to increase- this is because of photosynthesis
What did the increasing amount of O2 in the atmosphere allow?
More complex life to be established and evolved
When do combustion reactions occur?
When you burn substances in oxygen
What is a complete combustion?
When you burn a substance in plenty of oxygen
What is the general equation for complete combustion reactions?
Fuel + Oxygen -> Carbon Dioxide + Water Vapour