Salts And Electrolysis Flashcards
What are the similarities between alkalis and bases?
- both release ions in water
What does an ‘ acid + metal ‘ make?
A salt + hydrogen
What happens at the negative electrode in the electrolysis of aqueous solutions? 2
- The less reactive element ( between hydrogen and the metal ) is produced at the negative electrode
- and the metal will stay in solution
Why would thermosoftening polymers not be suitable for packaging very hot food?2
They would melt because of their low melting point
because of their weak intermolecular forces
When electrolysis happens in water what gas is given off?
Oxygen gas as discharge from hydroxide ions
What is two ways to identify a base?2
- hydroxides
- oxides
What happens when you react an acid with a metal?
Hydrogen gas is formed along with the salt
What is a salt?
A compound formed in a neutralisation reaction
Define electrolysis?
The process of passing an electric current through an ionic compound it through a molten substance Causing decomposition (splitting up)
What happens to ions in electrolysis?
Positive ions move to the negative electrode while negative ions move to the positive electrode
In electrolysis of electrons are gained what is the process called?
Reduction
Why can carbon nanotubes be used as lubricants?
Nanotubes can slide over eachother
Because no covalent bonds between the nanotubes
How do you make an insoluble salt? Eg with lead nitrate solution and potassium iodide solution
Add PIS to LNS and stir in a beaker
Precipitate of lead iodide formed
This can be filtered off the solution
Precipitate washed, distilled water and dried
Why can graphite conduct electricity?
Delocalised electrons can move through the graphite
What happens when two ions are attracted to an electrode?
The less reactive element gets discharged
List some protestors of alkalis?3
- soluble in water
- produce OH- ions
- pH 8-14
Why type of substance provides oh- ions?
Alkali
What ions are formed by alkalis in solutions?
OH- ions
What happens at the negative electrode during the electrolysis of brine?4
- Positive hydrogen ions are attracted to the negative electrode, as are the sodium ions
- hydrogen ions are less reactive so get discharged
- sodium ions stay in solution as they are more reactive
- the hydrogen atoms formed bond together and are given off as hydrogen gas
Why do farmers put ammonium nitrate on their farmland?
It provides minerals that help plants to grow
What happens at the positive electrode in the electrolysis of aqueous solutions?
Hydroxide ions from water are often discharged and oxygen gas
In the electrolysis of aluminium what happens at the negative electrode and involving the electrode? (O2-) 3
Each oxide ion loses two electrons
The ions turn into oxygen atoms
They bond in pairs to from molecules of oxygen gas
The oxygen reacts with the positive carbon electrodes making carbon dioxide gas
What ions are formed by acids in solutions?
H+ ions
What happens to the products of electrolysis if the reaction happens in water? 2
- The less reactive element ( between hydrogen and the metal ) is produced at the negative electrode
- and the metal will stay in solution
Why use molten?
Ionic substances don’t conduct electricity
When melted ions are free to move and carry charge
Explain how an object is electroplated?4
- the metal to be plates is used as the negative electrode
- the positive electrode is made from the plating metal
- at the positive electrode the playing metal is oxidised
- at the negative electrode the plating metal is reduced
Describe the structure of a metal?
Lattic of positive ions
With delocalised electrons
What is a cryolite and why is it used in the extraction of aluminium oxide?
The molten cryolite lowers the melting point making the reaction more efficient
What method could be use to separate a precipitate from solution?
Filters room
What does using the word ‘weak’ in terms of an acid mean?
The acid is partially ionised in water
What state are all carbonates?
Solids
Sum up how to make an insoluble salt in two sentances?
Combining two different soluble salts
React together to form a precipitate
Uses of brine products?
Chlorine = bleach which kills bacteria
Pure hydrogen =’margarine
Sodium hydroxide = bleach, soap, paper
Why do we electroplated objects?2
- for industrial purposes for protection
- for cosmetic purposes for attractiveness
List some properties of acids?2
- pH 1-6
- produce H+ ions in solution
Why does a catalyst not have to be replaced often?
It is not used up
What do you observe when magnesium reacts with an acid?
Gets hot Hydrogen produced (bubbles) Magnesium goes into solution
Why can metals be shaped?
Made of layers
Which can slip over eachother