chemical change Flashcards
what is chemical change
a process in which results in a complete change of a compound when a new compound is formed
what are the characteristics of a chemical change
the interatomic forces such as covalent and ionic bonds are completely changed
atoms rearrange to form new substances
a gas can be formed (effervescence )
there can be a colour change
heat can be released or absorbed
an insoluble product can be formed. its called a precipitate ( an insoluble solid in a solvent )
how do we classify reactions
according to their enthalpy changes
( energy changes)
name the two types we can classify reactions
exothermic reaction
endothermic reaction
what is an exothermic reaction
a reaction in which there is a net release of energy
eg respiration , combustion
what is an endothermic reaction
a reaction in there is a net absorption of energy
eg photosynthesis
list the types of chemical reactions
synthesis reaction
decomposition reaction
gas forming reaction
precipitation reaction
neutralisation reaction
what is synthesis reaction
a reaction I which two or more substances react together to form a substance of greater molecular mass
wha is decomposition reaction
a reaction in which a substance breaks down to form 2 or more simpler molecules / substances
name the two types of decomposition reactions
thermal decomposition - uses heat to break down the substance
catalytic decomposition - uses a catalyst to break down substance
what is a catalyst
a substance which speeds up the rate of a chemical reaction , without being used out
what is a gas forming reaction
a reaction in which one of the products in. gas
there is an after verse of a gas
what is precipitation reactions
a reaction which produces an soluble solid ( precipitate )
what is a neutralisation reaction
none
