Chemical Change Flashcards
What does pH scale measure
How acidic or alkaline a solution is
What does it mean if a solution ahs a low or high pH
Lower pH of a solution is the more acidic it is
Higher pH of a solution the more acidic it is
What is neutral number on pH
7
How do strong acids ionise
They ionise completely in water.
How do week acids ionise
Do not fully ionise
What does pH of an alkali or acid measure the concentration of
It measures the concentration of H+ ions in the solution
For a decrease of 2 in the pH scale how much does the concentration of H+ ions decrease
100
Compare pH in a strong acid and a weak acid if they have the same concentration
Strong acid has lower pH than a week acid if they have the same concentration
What does the acid strength tell you
The proportion of the acid molecules ionise in water
What does concentration if an acid measure
Concentration measures how much acid there is in a certain volume of water
Can you have a dilute acid but its strong (y or n)
Yes
What is formed when metal oxides and hydroxides react with acids
Salt and water
What does metal carbinate form when it reacts with acid
Salt, water and carbon dioxide
How can you make a pure dry sample of a given solube salt (crystalisation)
Gently warn the dilute acud using a bunsen burner then turn iff the bunsen burner. Add the insolube base to the acid gradually until nonmore reacts. All acid is nutrialised if excess solid sinks to bottom. Then filter out excess solid to get salt solution. To get pure dolid crystals of salt use an electric heater to evaporate some of the water. Crystals of salt should be formed. This is called crystalisation.
What does reactivity series do
List metals in order of their reactivity compared to other substances
What does the position of a metalin the reactivity series determine
Higher a metal is the more reactive it is. Vice versa
How can you find reacticity of a metal
Measuring the temperature change of the reaction with an acud or water over a set period of time
When metal reacts with acids what is formed
Acid+metal–>salt+hydrogen
What do you get when metal reacts with water
Metal+water–>metal hydroxide+hydrogen
What is gain of oxygen called
Oxidation
What is loss of oxygen called
Reduction
How do metals that are higher than catbon in the reactivity series get extracted
Extractes using electrolysis
How do metals lower than carbon in the reactivity series have to be extracted
They have to be extracted by reduction using carbon
What is loss of ekectrons called
Oxidation
What is a gain of electrons called
Reduction
What is redox
REDuction and OXidation at the same time
How will different reactive metals displace eachother
More reactive metals will displace (remove) less reactive metals from its compound
If you put iron in copper sulfate what will happen
Iron (more reactive metal) will replace itself for copper (less reactive metal) in the compound
What is purity of a substance
Only contains one compound or element throughout
What is combustion
Fuel is burned and reacts with oxygen to release energy
