Chapter 5 Chemical Changes Flashcards
Write the word equation for the reaction between a metal and oxygen.
When metals react with oxygen, metal oxides are formed.
metal + oxygen → metal oxide
What is it called when a metal reacts with oxygen to form a metal oxide OR when an atom loses electrons?.
When a metal reacts with oxygen to form a metal oxide this is called oxidation.
Oxidation is also used to describe the loss of electrons.
What 2 things can the term reduction refer to?.
When oxygen is lost from a compound in a reaction we call this reduction.
Reduction is also used to describe the gain of electrons.
What does the acronym OIL RIG stand for?
OIL RIG can be used to remember what happens to electrons during oxidation and reduction.
Oxidation is loss. Reduction is gain.
What sort of ions do metals always make? Why do they do this?
Metals react to form positive ions. This gives them a full outer shell of electrons which makes them more stable.
Are metals that lose electrons more readily more, or less reactive?
Metals which lose electrons more readily are more reactive.
What do we call it when we arrange metals in order of reactivity?
Metals are arranged in order of reactivity in the reactivity series.
What can we react metals with to determine how reactive they are?
The order of reactivity of metals can be determined experimentally by reacting metals with water or dilute acids.
Name 4 metals that will react with water.
Potassium, sodium, lithium and calcium will react with water.
Describe in detail what happens when potassium reacts with water.
When potassium reacts with water it produces hydrogen gas, melts, explodes and burns with a lilac flame.
Describe in detail what happens when sodium reacts with water.
When sodium reacts with water it melts, produces hydrogen gas and may burn with an orange flame.
Describe in detail what happens when lithium reacts with water.
When lithium reacts with water it produces hydrogen gas. It doesn’t get hot enough to melt.
Write a word equation for the reaction of a metal with water.
When metals react with water hydrogen gas and a salt are produced.
metal + water → salt + hydrogen
Describe how to name salts.
When naming salts the first part of the name comes from the metal and the second part comes from the acid.
Eg: magnesium + hydrochloric acid → magnesium chloride + hydrogen gas
Why must equations be balanced?
Equations must be balanced so there are the same number of atoms of each element on each side of the equation.
Eg: Mg(s) + 2HCl(aq)→ MgCl2(aq) + H2(g)
Name the 2 non-metals that are included in the reactivity series.
The non-metals hydrogen and carbon are included in the reactivity series.
What will metals that are more reactive than hydrogen react with?
Metals more reactive than hydrogen will react with dilute acid.
Give the mnemonic for remembering the reactivity series then write out the reactivity series.
The reactivity series is:
What is the rule for displacement of metals?
A more reactive metal can displace a less reactive metal from solution.
What are the results of displacement reactions used to determine?
Results of displacement reactions can be used to determine the reactivity of metals.
What type of reaction are displacement reactions an example of? (higher only)
Displacement reactions are redox reactions. One atom is losing electrons while another is gaining electrons.
What type of equations can be used to represent displacement reactions? (higher only)
Displacement reactions can be represented using ionic equations.
Eg: Fe(s) + Cu2+(aq) → Fe2+(aq) + Cu(s)
Decide if these half-equations are examples of oxidation or reduction
Fe(s) → Fe2+ + 2e-
Cu2+(aq) +2e- → Cu(s)
(higher only)
Ionic equations for redox reactions can be represented by 2 half-equations to show what happens to each reactant.
Eg: Oxidation Fe(s) → Fe2+ + 2e-
Reduction Cu2+(aq) +2e- → Cu(s)
What do you get when you put together 2 half-equations? What must be true of the electrons in this final equation? (higher only)
The 2 half-equations can be put together to make the ionic equation. The number of electrons on the right must equal the electrons on the left.