chemistry term 3 Flashcards
(45 cards)
describe how the water cycle works
(the energy to drive this cycle comes from the sun
- water evaporates from areas of water (sea, lakes), and enters the atmosphere
- water cools and turn into liquid water, forming clouds (tiny water droplets)
- water droplets stick together
- rain clouds are formed
- water falls back to the surface as rain, hail or snow
- water is either absorbed by plants or back to sea
describe how the carbon cycle works
- respiration and combustion release carbon dioxide into the air
- carbon dioxide in air
- photosynthesis in plants remove carbon dioxide from air
- photosynthesis in plants releases oxygen into the air
- oxygen in air
- respiration and combustion remove oxygen from the air
what percentage of clean air is nitrogen ?
76%
what percentage of clean air is oxygen
21%
what percentage of clean air is argon ?
0.9%
name 4 air pollutants and how they’re produced
sulphur dioxide - burning fossil fuels
carbon monoxide - forms when combustion reactions aren’t fully completed
nitrogen dioxide - reactions of nitrogen oxides with air
methane - farm
boiling point for nitrogen and oxygen
nitrogen =
-196 degrees Celsius
oxygen =
-183 degrees celsius
what is an oxide ?
compound of oxygen with other element(s)
name the 4 type of oxides
acidic oxides
-produces an acidic solution when combined with water
basic oxides
-makes a base when combined with water
amphoteric oxides
-makes an alkaline solution when combined with water. behaves like both an acid and a base
neutral oxides
-no reaction when dissolved in water
metal element + acid —–> salt + ?
hydrogen
compound (base) + acid ——> salt + ?
h2o (Water)
acids _______ h+ ions when dissolved in water
acids PRODUCE h+ ions when dissolved in water
bases ____ __ h+ ions and produce ___ (hydroxide ions) when dissolved in water
bases TAKE IN h+ ions and produce OH- (hydroxide ion) when dissolved in water
noble gasses are very ______ and unlikely to form chemical _____ because they have very little tendency to ____ or ____ electrons because they contain a full valence of ________
noble gasses are very STABLE and unlikely to form chemical BONDS because they have very little tendency to GAIN or LOSE electrons because the contain a full valence of ELECTRONS
what is electrolysis ?
separation of elements
(example: aqueous sodium chloride.
negative electrode = hydrogen gas
positive electrode = chlorine gas
solution of sodium hydroxide also forms)
what are positive metal ions attracted to and why?
attracted to the negative electrode where they gain and form metal atoms
what is the atomic number
number of protons & electrons
how do you find the number of neutrons
mass number subtracted by atomic number
group 1 elements have _ electron in their outer shell
group 2 elements have _ electrons in their outer shell
group 3 elements have _ electrons in their outer shell
group 8 elements have _ electrons in their outer shell
group 1 elements have 1 electron in their outer shell
group 2 elements have 2 electrons in their outer shell
group 3 elements have 3 electrons in their outer shell
group 8 elements have 8 electrons in their outer shell
etc..
diamond and graphite,
each carbon atom is linked to _ other carbon atoms by strong ________ bonds
each carbon atom is linked to 4 other carbon atoms by strong covalent bonds
sodium oxide is
acidic or alkaline ?
alkaline
pH scale, the higher the value the more ________
alkaline
universal indicator.
acids show up as … ???
red - yellow
universal indicator.
alkalies show up as … ???
blue - purple
