C1 - Air and Water Flashcards
What where the main ideas in daltons atomic model
Atoms are tiny solid balls which can’t be broken down
All atoms of an element are identical
Atoms of different elements are different
Atoms from different elements combine to make compounds
Atoms are rearranged during a chemical reaction to make new substances
What did Thomson discover
He discovered electrons
Who discovered electrons
Thomson
What is an isotope
An atom with the same number of protons and electrons but with a different number of neutrons
What is formed in the reaction between group 1 elements and water
Metal hydroxide and hydrogen
What is the appearance of chlorine
yellow green gas
What is the appearance of bromine
deep red liquid
What is the appearance of iodine
grey solid
What is the colour of iodine as a gas
Purple
Formula for ammonia
NH3
Formula for chlorine
Cl2
Does breaking a bond release or require energy
breaking bonds requires energy
overall energy change (in a chemical reaction) =
energy required to break bonds / energy released by forming bonds
if the overall energy change is negative was it endo or exo
exothermic
What was phase 1 of our atmosphere?
volcanoes gave out gases
What gases did volcanoes release into our atmosphere
N2, H2O, NH3
What is phase 2 of our atmosphere
As the earth cooled, the water vapour formed our oceans
Algae and plants began absorbing CO2
What is phase 3 of our atmosphere
Plants and algae, produced oxygen into our atmosphere
Why does coal cause acid rain
Because coal contains sulphur impurities, and when coal is burnt, sulphur dioxide is released
How does sulphur dioxide cause acid rain
When it mixes with clouds it forms dilute sulphuric acid, which is acidic
How are nitrogen oxides made
the heat from combustion causes oxygen in the air and nitrogen in the air to react together
What are some effects of acid rain
kills plants, damages buildings, and corrodes metals
What do catalytic converters do
remove nitrogen oxides from exhaust gases
What doe acid gas scrubbers do
reduce harmful gases from power station emissions
Test for chlorine gas
Chlorine bleaches damp blue litmus paper, turning it white
What is the activation energy in an endothermic reaction
the distance from the reactants line to the top of the curve
are most neutralization reactions exo or endothermic
exothermic
does breaking a bond require or release energy
breaking a bond requires energy
does making a bond require or release energy
making a bond releases energy
if the overall energy change is negative, is it an endo or exothermic reaction
exo
What was the first phase of our atmoshpere
Volcanoes gave out gases
What gases did volcanoes release
ammonia, methane, water and co2
What was the second phases of our atmosphere
the oceans and plants in the oceans absorbed the carbon dioxide in our atmospehre
What was the third phase of our atmosphere
the plants and algae produce oxygen
What is released during incomplete compustion
CO, H2O, and carbon particulates in the form of soot
What other gas is made during combustion of coal, and why does this happen
sulphur dioxide is made, and this happens because` of sulphur impurities found in coal
How do power stations reduce the emissions of harmful gasses
acid gas scrubbers
How do cars reduce the emissions of harmful gasses
catalytic converters
ammonia
NH3
Test for hydrogen
Squeaky pop
Test for oxygen
glowing splint will reignite
Test for CO2
gas will turn limewater a milky white
Test for chlorine
Chlorine will bleach a blue piece of DAMP litmus paper white
In a hydrogen fuel cell, which electrode is positive
the cathode
what enters the fuel cell on the negative, anode side
H2
what enters the fuel cell on the positive, cathode side
O2
What happens to the H2 at the anode (negative)
It oxidises the hydrogen, and the electrons flow through the wire running from the anode to the cathode. The H+ ions then travel through the electrolyte, to the cathode (positive)
What happens at the cathode in a fuel cell
the electrons and the H+ion combines with the O2 to form water
What pH is considered a safe drinking water
6.5 - 8.5
What are the 4 steps of water treatment
pass through wire mesh to catch large solids
pass through sand and gravel to catch smaller solids
pump air through water to encourage the growth of aerobic bacteria (breaks down organic matter)
chlorine is pumped through, which kills micro organisms
What is reverse osmosis
Salty water is passed through a membrane which only allows water to pass through
