Chemistry common Flashcards
Volume of one mole of gas
1 mole of any gas at 20℃ occupies 24dm³
How do you go from dm³ to cm³
cm to dm is divide by 10
cm³ to dm³ is divide by 1000(10³)
goes cm, dm, meter
What do acids and bases release in water
Acids H+ ions
Alkali OH-
What does a strong acid mean
When react with water all the particles release H+ ions (H+ is just a proton)
Why do strong acids increase rate of reaction
Strong acids release a lot of H+ ions
H+ ions used in reactions
What is PH the measure of
PH measures the concentration of H+ or OH-ions
Chemical formular of
Hydrochloric acid
Sulfuric acid
Nitric Acid
Sulfuric H₂SO₄
Hydrochloric HCl
Nitric HNO₃
Difference between Alkali and base
Base is something that neutralises acids
Alkali is a base that is soluble in water(think alkali metals react to form alkali that is dissolved in water)
What does Acid and a metal hydroxide produce and why
Makes a salt and water
water comes from H+ ion in acid and the OH- in the hyrdoxide
What does Acid and metal oxide produce and why
Makes a salt and water
Water comes from H+ ion from acid and the O²- from the oxide
What does an acid and a metal carbonate produce and why
Makes a salt and water and carbon dioxide
Water is produced for the same reason as a metal oxide and CO2 is produced from the carbonate
Recall the reactivity series
Potassium, sodium, lithium, calcium, magnesium aluminium carbon zinc iron hydrogen copper silver gold
Name for negative and positive electrode
Cathode is negative
Anode is positive
Describe the products of electrolysis of a molten compund
Cryolite used to lower melting point ,the positive ion in the compound(e.g. Al³+) gets attracted to the cathode. The negative ion in the compound(O²-) gets attracted to the anode, if oxygen involved it reacts with the rods and produces CO2 using up the rod
Describe the products of electrolysis in a aqueous solution
At cathode(-)
Water ionises and splits into H+ and OH-. At the cathode one of the two positive ion gets produced there ,either H+ or metal+ ion, the least reactive of the two gets produced at the cathode(tip because the more reactive one wants to stay in its compound)
At anode(+)
Oxygen(from OH-) will form and water unless a halide is present . The half equation for Oxygen is you start off with OH- ion and it turns to O₂ + H₂O + Electrons needs balancing
Which of these is an alkali or a base
Metal Hydroxide
Metal Carbonate
Metal oxide
Metal hydroxide is alkali as it dissolves in water
Metal carbonate is base as it doesn’t dissolve in water
Metal Oxide base doesn’t dissolve in water (think copper oxide black powder that wont dissolve)
How do you write an Ionic equation
Separate all the ions in the equation and write their products
Describe structure of cell
Two electrodes that can conduct electricity in contact with an electrolyte(liquid that has free moving ions to conduct electricity)
Why does a battery produce electricity
chemical reaction between electrodes and electrolyte make a charge difference between electrodes making electrons flow
what effects cell voltage
difference in reactivity between metals
the electrolyte
how to create battery
connect cells in series increases voltage
Why do cells stop working
chemicals have all reacted so no voltage is produced
If rechargeable can apply current which reverses the reaction
How does fuel cells work
hydrogen added to the -ve electrode and oxides loosing electrons and moves towards the +ve electrode through the electrolyte.
At +ve electrode the oxygen electrons and hydrogen ions react to form water
