module 3 Flashcards
what are the two types of changes
- physical: does not result in the formation of new substances
- chemical: involves the formation of new substances
indicators of a physical reaction
- change in state
- change in size/shape
eg. synthesis and decomposition
indicators of a chemical change
- production of bubbles that indicates the a gas has been formed
- production of odour
- change in temperature
- formation of a precipitate
what are the six types of reactions
- synthesis
- decomposition
- combustion (+incomplete)
- precipitation
- acid + base
- acid + carbonate
synthesis reaction
reaction between two or more substances to form a new substance
- two metals –> ionic
- non-metal + metal –> covalent
decomposition
where one reactant is broken into two or more constituent substances and requires the input of energy to break bonds
- thermal decomposition
- electrolysis
- photolysis
combustion
- burning a substance in oxygen at high temperatures to form new products
- exothermic
- complete: fuel + oxygen –> water + carbon dioxide
- incomplete: fuel + oxygen –> water = carbon dioxide + carbon monoxide + soot (C)
precipitation
mixing two solutions together resulting in the formation of a insoluble solid –> precipitate
- predicted using solubility rules
- nagsag
- care bear stroller
acid base (neutralisation)
- acid + base –> salt + water
- exothermic
acid carbonate
- acid + carbonate –> salt + water + carbon dioxide
process of cycads
- cut up fruit and place in mesh bags
- soaked in water to leach out the toxins
- heat the fruit which causes thermal decomposition of toxins
- fruits in the mesh bags are places in a running stream of water to leach out the toxins
- fermentation to leach out the toxins
metal and steam
hydrogen gas and metal oxide
metal and water
metal hydroxide and hydrogen gas
metal and oxygen
metal oxide
metal and dilute acid
salt and hydrogen gas
displacement reactions
the more reactive metal displaces the less reactive metal ions from the solution