4.chemical changes Flashcards
what is the pH scale?
a measure of how acidic or alkaline a solution is that goes from 0-14
a solution with a pH of 7 is…
neutral
anything that forms a solution with a pH if less than 7 is an…
acid.Lower the pH,more acidic the solution
anything that forms a solution with a pH of greater than 7 is an
alkali.The higher the pH,the more alkaline a substance is
what is happens when a metal reacts with oxygen?
metal oxide is formed and an oxidation reaction takes place so the metal atoms have been oxidised
what is gaining oxygen called?
an oxidisation reaction
what is losing oxygen called?
reduction reaction
reaction between calcium and copper oxide
calcium+copper oxide —>calcium oxide+copper
in the reaction between calcium and copper oxide,which atoms are oxidised and which are reduced?
the products of the reaction are calcium oxide and copper which means the calcium has gained oxygen(so oxidised) and the copper loses oxygen(so reduced)
reaction of potassium and water
-forms potassium hydroxide and hydrogen
-vigorous reaction
how does potassium ,sodium and lithium react with water?
react very rapidly with water at room temperature
how does calcium react with water at room temperature?
reacts quite rapidly with water at room temperature
how does magnesium,zinc,iron and copper react with water at room temperature?
no reaction
how does potassium,sodium and lithium react with dilute acid?
dangerously fast reaction with acids
how does calcium react with dilute acid?
extremely vigorous reaction
how does magnesium react with dilute acid?
rapid reaction
how does zinc react with dilute acid?
quite rapid reaction
how quickly does iron react with dilute acid?
quite slow reaction
how does copper react with dilute acid?
no reaction
what determines how rapidly a metal reacts?
when metals react,they lose electrons and form positive ions.The higher up the reactivity series a metal is,the more easily it will form positive ions
