Chemestry end of term year 8 revision Flashcards
What are examples of chemical reactions
boiling melting Shredding freezing
What are examples of physical reactions
Cooking an egg ,heating sugar till it becomes caramel, rusting of iron and burning of wood
Metals
Conduct electricity, have high melting and boiling points, are malleable, have high density and are good insulators
Non metals
Have low density, low melting and boiling points, are brittle and dull
What is oxidation
When a chemical substance changes due to the addition of oxygen
What happens in displacement
When a metal higher on the reactivity series displaces another metal from its compound
What is the equation for corrosion
Metal +oxygen>carbon dioxide
What is the equation for rusting
Iron+oxygen>iron hydroxide
What is thermal decomposition
When a chemical substance breaks down into at leat two chemical substances due to heat
What is the equation of thermal decomposition
Metal oxide heat> metal+carbon dioxide
What do endothermic reactions do
Take energy from their surroundings and the temperature of surroundings decreases
How are sedimentary rocks formed
When sediment(rocks that have been erode ) builds up under water into layers and the water is released because of pressure forming sedimentary rocks
How are metamorphic rocks formed
When igneous or sedimentary rocks are melted or formed together due to heat and pressure to create new metamorphic rocks
How are igneous rocks formed
From molten liquid which has cooled then solidified.
What is the difference between intrusive and extrusive igneous rocks
Intrusive rocks cool from magma very quickly in a volcanic eruption and have few crystals while extrusive rocks are formed inside the volcano slowly and take longer to form meaning they have bigger crystals
