Chemistry - Acids + Bases

Question 1

what is an acid, give examples, properties?

Answer 1

a substance that releases hydrogen ions into an aqueous solution (containing water). can donate a proton or accept an electron pair in reactions. eg hydrochloric acid

properties
corrosive
sour taste
turns red with litmus paper
reacts with some metals, releasing hydrogen gas and leaving salt behind
conducts electricity
neutralised by bases
pH < 7

Question 2

what is a base, give examples, properties?

Answer 2

substance that releases hydroxide ions. it accepts protons or donates a pair of valence electrons to form a bond. If a base can be dissolved in water it is also known as alkali.
eg - caustic soda
Properties:
caustic
soapy/slimy feel
turns litmus paper blue
bitter taste
conducts electricity
neutralised by acids
pH > 7

Question 3

what is pH

Answer 3

measure of hydrogen ions in a solution, in acidic solutions, there are more hydrogen ions than hydroxide ions

Question 4

how do we measure pH

Answer 4

indicators - chemicals that change colour to show whether a substance is acidic, neutral or basic
litmus paper - common type of indicator

Question 5

what is a mixture

Answer 5

substance made from two or more pure substances or chemical stirred together

Question 6

soluble vs insoluble

Answer 6

soluble - when a substance can be dissolved
insoluble - when it cannot be dissolved

Question 7

define the following terms:
solution
solvent
solute
concentration

Answer 7

solution - when things mix really well
solvent - is the substance that dissolves
solute - the substance that dissolves the other
concentration - measure of the amount of solute dissolved in a known amount of solvent

Question 8

what are the 4 main types of chemical reactions?

Answer 8

synthesis
decomposition
single replacement
double replacement
see lesson 10

Question 9

what is a chemical reaction?

Answer 9

change in which atoms are rearranged to form at least one new substance. the chemicals that react are called reactants.
the new substances formed are called products

Question 10

combustion vs corrosion

Answer 10

combustion -
a rapid reaction with oxygen that releases energy in the form of heat or light

corrosion
the breakdown of metals due to their reaction with other chemicals

Question 11

what is photosynthesis + chemical equation

Answer 11

process that uses light energy to make food from simple chemicals
equation: 6CO2 + 6H2O -> C6H12O6 + 6O2

Question 12

what is aerobic respiration + chemical equation

Answer 12

chemical process in which food is broken down to release energy
equation: C6H12O6 + 6O2 ->6CO2 + 6H2O