3.1 Chemical reactions

Question 1

(6) differences between physical and chemical change

Answer 1

(1) change in physical property vs chemical property
(2) without change in composition vs rearranged atoms
(3) no new substances formed vs yes
(4) small amount of energy absorbed vs large
(5) involves a change in state vs none
(6) easy to reverse vs difficult

Question 2

(2) chemicals separated using physical properties

Answer 2

mixtures and pure substances

Question 3

(2) chemicals separated using chemical properties

Answer 3

compounds and elements

Question 4

synthesis reaction

Answer 4

formation of more complex substance from less complex substances

Question 5

decomposition reaction (3 types)

Answer 5

breakdown of complex substances into less complex ones
(1) thermal (by heat)
(2) photo (by photons)
(3) electrolysis (using electric currents)

Question 6

combustion reaction (2 types)

Answer 6

substances with oxygen to make oxide + water

(1) complete combustion = CO2 and H2O
(2) incomplete combustion = CO and H2O

Question 7

precipitation reaction

Answer 7

two aqueous substances form an insoluble solid

Question 8

neutralisation (acid/base) reaction

Answer 8

acid + base => salt + H2O

Question 9

acid/carbonate reaction

Answer 9

acid + carbonate => salt + H2O + CO2

Question 10

solubility trend: SNAAP rule

Answer 10

any salt with these ions are soluble:

Sodium
Nitrate
Ammonium (NH4 +)
Acetate (CH3COO-)
Potassium

Question 11

ATSI detoxication of food (3 methods)

Answer 11

(1) cooking: heat decomposes toxic compounds
(2) leaching: water dissolves toxic compounds
(3) fermentation: microorganisms decompose toxic compounds