10.1-10.4 Acids, Bases and Salts

Universal indicator

Universal indicator

________ is a mixture of different indicatorswhich is used to measure the pH.

hydrochloric acid

For example ________ always produces salts that end in chloride and contain the chloride ion, Cl-

Zinc

________ oxide reacts with sulfuric acid to produce zincsulfate.

alkalis

When ________ react, they gain electrons to form negative hydroxide ions (OH)-

limestone

Crushed or powdered ________ (calcium carbonate) or lime (calcium oxide) or slaked lime (calcium hydroxide) is added to neutralise the excess acidity in the soil.

precipitate

If a(n) ________ is formed from either NaOH or aqueous ammonia then it means that the hydroxide is insoluble in water.

metallic character

The ________ of the element influences the acidic or alkaline behaviour of the molecule.

compound

A salt is a(n) ________ that is formed when the hydrogen atom in an acid is replaced by a metal.

Alkali

________ is added to the substance with gentle warming followed by the test for ammonia gas using damp red litmus paper.

Soils

________ may become acidic from acid rain, overuse of fertilisers which contain ammonium salts or by the excessive breakdown of organic matter by bacteria.

Bases

________ are substances which can neutralize an acid, forming a salt and water.

pH scale

The ________ is a numerical scale which is used to show how acidic or alkaline a solution is.

Acidic oxides

________ are formed when a non- metal element combines with oxygen.

Amphoteric oxides

________ are a curious group of oxides that can behave as both acidic and basic, depending on whether the other reactant is an acid or a base.

Metal oxides

________ and metal hydroxides (alkalis) can act as bases.

Acids

________ are proton donors as they ionise in solution producing protons, which are H+ ions.

OH ions

Bases (alkalis) are proton acceptors as they ionise in solution producing ________ which can accept protons.

basic solution

When dissolved in water they produce a(n) ________ with a high pH.

ammonia

Even though ________ is itself a weak base, it is very volatile and can easily be displaced from the salt by another alkali.

acidic solution

When dissolved in water they produce a(n) ________ with a low pH.

Salts

________ are an important branch of chemistry due to the varied and important uses of this class of compounds.

Ca2+ ions

________ can be distinguished from Zn2+ and Al3+ as calcium hydroxide precipitate does not dissolve in excess NaOH but both zinc hydroxide and aluminium hydroxide do.

Ammonium salts

________ undergo decomposition when warmed with an alkali.

colour of the flame

The ________ is observed and used to identify the metal.

neutralisation reaction

When bases react with an acid, a(n) ________ occurs.

Bases

________ are usually oxides or hydroxides of metals.

Acids

________ have pH values of below 7, have a sour taste (when edible) and are corrosive.

Acids

________ are substances that can neutralise a base, forming a salt and water.

Example

Sodium Hydroxide

It goes from 1

14 (extremely acidic substances can have values of below 1)

Example of a weak acid

propanoic acid

Example for a weak base

aqueous ammonia