Chemical changes Flashcards
State the order of the reactivity series.
Potassium
Sodium
Calcium
Magnesium
Aluminum
Carbon
Zinc
Iron
Tin
Lead
Hydrogen
Copper
Silver
Gold
Metal + Acid–>
Salt + Hydrogen
Metal + water–>
Metal hydroxide + Hydrogen
Which metals can react with water?
Metals more reactive than calcium
What is oxidation and reduction?
Oxidation- Loss of electrons
reduction- gain of electrons
Metal + oxygen–>
Metal oxide
How do we separate metals from metal oxides?
By reduction using carbon
Metal oxide + carbon–>
Metal + carbon dioxide, this only happens with metals less reactive than carbon
How are metals more reactive than carbon extracted?
Electrolysis, very expensive
How are metals less reactive than carbon extracted?
Using carbon displacements
What is a redox reaction?
A reaction where oxidation and reduction both happen
Metal + Acid–>
Salt + Hydrogen
What is a neutralization reaction?
Acids + Alkalis
Metal oxide + Acids–>
Salt + Water
Metal hydroxide + Acid–>
Salt + Water
Metal carbonate + acid–>
Salt + Water + Carbon Dioxide
RP1: How do we make soluble salts?
Gently heat dilute acid with Bunsen burner, keep adding small amounts of insoluble base until it won’t dissolve, filter it out and then heat using water bath to get crystals.
What is the pH scale?
A measure of how acidic or alkaline a substance it (1-14)
What are indicators and pH probes used for?
detecting the pH of substances (probe= machine connected to pH meter)
Define acid.
Any substance that dissociates H+ ion in aqueous solution with pH less than 7
Define base.
Any substance with pH above 7
Define Alkali
A base (pH above 7) that dissociates OH- ions in aqueous solution
What is the difference between a base and an alkali?
Alkali is a type of base that dissociates OH- ions in aqueous solution
What is the formula for neutralisation?
Acid + Base–> Salt + water
Give 3 examples of acids and their formulas.
Hydrochloric- HCl
Sulfuric- H₂SO₄
Nitric- HNO₃
Give 2 examples of bases and their formulas.
Sodium hydroxide- NaOH
Calcium carbonate- CaCO₃
What is pH?
The concentration of H+ ions
How do we know if an acid is strong?
If it dissociates H+ ions completely in water, an irreversible reaction
How do we know if an acid is weak?
If it partially dissociates in water, producing a lower concentration of H+ ions.
What is important to know about concentration and strength of an acid?
concentration does not equal strength
Between each pH level, the number of H+ ions increase by…
x10 H+ ions
