Chemical Changes Flashcards
What is a chemical reaction?
When the substance becomes something else and can not be reversed
What are signs that a chemical reaction has occurred
Change in temperature
Formation of a precipitate
Change in colour
What reaction re-arranges atoms?
Chemical reactions
Do chemical reactions always make a new substance?
Yes
Are physical changes reversible
Yes
Do chemical reactions involve energy transfers
Yes
Give an example of a chemical reaction
Baking raw cake to cooked cake
Give an example of a physical change
Boiling water to make steam
What does a fuel need to burn?
Oxygen and heat
What does combustion mean?
Burning
What’s the word equation for burning
Fuel+ Oxygen —-> carbon dioxide + water (vapour)
What reaction is burning something?
Oxidation reaction
What is thermal decomposition?
Breaking a substance down, using heat, into 2 or more products
What’s the most reactive Carbonate?
Calcium carbonate
What’s the least reactive carbonate
Copper carbonate
What is endothermic
Heat energy is taken in from surroundings TEMPERATURE FALLS
What is exothermic?
When heat energy is given out to the surroundings TEMPERATURE RISES
What is a physical reaction?
A substance that changes state but doesn’t become anything else
