Chemical Reactions and Dynamics

Question 1

physical vs chemical properties

Answer 1

• physical (alterations to physical properties without changing chemical composition)
• chemical (change to chemical composition, formation of new substance/s)

Question 2

Mixtures

Answer 2

• not pure
• variable composition and properties
• can be physically separated

Question 3

2 types of pure substances

Answer 3

elements, compounds

Question 4

observing chemical reactions

Answer 4

• alters the way atoms are bonded together
• types of atoms and total weight remain the same

Question 5

signs of chemical change

Answer 5

• original substance disappears
• change in colour
• gas is made
• change from solution to suspension

Question 6

simple basis of a chemical equation

Answer 6

reactant + reactant = product/s

Question 7

conservation of mass

Answer 7

atoms cannot be created or destroyed in chemical changes

Question 8

exothermic reactions

Answer 8

energy released, returns much more energy than the activation energy. reactants have more energy than the products, releasing heat
reactants -> products + heat

Question 9

endothermic reactions

Answer 9

absorb heat energy, require supplied energy
reactants + heat -> products

Question 10

carbonate

Answer 10

compounds containing CO3 and a a metal

Question 11

combustion

Answer 11

exothermic, require oxygen to burn

Question 12

combustion of carbon-based fuels

Answer 12

fuel burns -> atoms in fuel compound combine with oxygen to form an oxide compound

Question 13

incomplete combustion

Answer 13

deficiency of oxygen and fuel isn’t burnt fully

Question 14

corrosion

Answer 14

• corrosion is a natural electrochemical process that causes materials to deteriorate in chemical reactions with their environments

Question 15

tendency of ions

Answer 15

metals lose electrons (+ charge)
non metals gain electrons (- charge)
- ionic compounds usually soluble in water

Question 16

polyatomic ions

Answer 16

made up of 2 or more bonded atoms in a group with 1+ extra electrons

Question 17

precipitation reaction

Answer 17

ions form together into a crystal lattice and tiny solid particles that slowly precipitate to the bottom

Question 18

acids

Answer 18

• ionic compounds that dissolve in water
• release h+ ions

Question 19

bases

Answer 19

• strong bases (alkalis)
• compound which dissolves in water and releases hydroxide ions (OH-)

Question 20

neutralisation

Answer 20

when an acid is mixed with a base, each destroys that other
- produces neutral water and salt

Question 21

photosynthesis

Answer 21

6CO2 + 6 H2O + light -> C6H12O6 +6 O2
carbon dioxide + water +light -> glucose + oxygen

Question 22

cellular respiration

Answer 22

C6H12O6 + 6O2 -> 6H2O + 6CO2 + energy (ATP)
glucose + oxygen molecules -> carbon dioxide + water + energy

Question 23

valency

Answer 23

combining power of an element
- metals in I, II, III create cations
- nonmetals in V, VI, VII form anions

Question 24

cations vs anions

Answer 24

cations (pos charge, lose electrons)
anions (neg charge, gain electrons)

Question 25

naming ionic compounds

Answer 25

metal first, end of nonmetal to ide

Question 26

organic compounds

Answer 26

based on carbon and hydrogen, often contain oxygen make up for a vast majority of known compounds

Question 27

synthesis reactions

Answer 27

two chemical species combine to produce a single compound A + B -> AB

Question 28

decomposition reactions

Answer 28

a single compound decomposes to produce two or more chemical species AB -> A + B

Question 29

acids and metal carbonates

Answer 29

metal carbonates react with acids to produce salt, water and carbon dioxide gas Acid +Metal carbonate -> salt + water + carbon dioxide

Question 30

acids and active metals

Answer 30

acids react with active metals to produce salt and hydrogen gas

Question 31

precipitation reaction

Answer 31

solutions are mixed together to produce an insoluble solid Solution A + Solution B -> insoluble solid C + solution D

Question 32

complete combustion of hydrocarbons

Answer 32

oxygen produces carbon dioxide and water as biproducts hydrocarbon + oxygen -> carbon dioxide + water

Question 33

fossil fuel combustion

Answer 33

hydrocarbons releasing original energy gained from the sun and combustion can be complete or incomplete

Question 34

complete combustion

Answer 34

burn hydrocarbons in an excess of air, all carbon to carbon dioxide

Question 35

incomplete combustion

Answer 35

hydrocarbon converted to a mixture of water, carbon monoxide and soot

Question 36

aerobic respiration

Answer 36

form of oxidation reaction, slower than burning of fossil fuels but is more controlled

Question 37

factors that affect rate of reaction

Answer 37

- occurs through collision theory temperature (increases kinetic energy)_ concentration (increase no. of reactant particles) catalysts (lowers activation energy) pressure (higher no. of collisions) particle size (larger particles = more collision)