Reactivity Series and Acids Flashcards
What is the reactivity series
Potassium, Sodium, Lithium, Calcium, Magnesium, Aluminium, Zinc, Carbon, Iron, Hydrogen, Tin, Lead, Copper, Silver, Gold
Which metals react with cold air?
From potassium to silver (Everything except gold)
Which metals react when heated in warm air?
Potassium to copper
metal + cold water =
metal hydroxide and hydrogen
metal + steam =
metal oxide + hydrogen
Why does aluminium not react with steam?
Aluminium is very quick to form aluminium oxide when in the presence of oxygen which stops the steam from coming in contact with the aluminium.
what happens when magnesium is placed into cold water and why?
There is almost no reaction. Magnesium becomes coated with the insoluble magnesium hydroxide which prevents water coming into contact with it.
What happens when a metal reacts with cold air?
They form a metal oxide
What would happen if you reacted potassium or sodium with an acid?
It would explode
what happens when magnesium is reacted with steam?
magnesium burns with a bright, white flame producing hydrogen and white magnesium oxide
Which metals react with hydrochloric and sulfuric acids?
From calcium to tin.
What will form when a metal reacts with a hydrochloric or sulfuric acid?
Hydrogen and a metal sulfate/chloride is formed.
What can you tell if a displacement reaction occurs between two metals?
The metal that takes the oxygen is more reactive.
What will happen if magnesium is heated with carbon dioxide?
It will become magnesium oxide and carbon.
What is oxidation?
The loss of electrons, gain of oxygen
What does it mean if a substance is oxidised?
It has lost electrons/gained oxygen
What is reduction?
The gain of electrons/loss of oxygen
What is a redox reaction?
A reaction in which one species is oxidised and another is reduced
What is a reducing agent?
A substance which reduces something else/gives electrons
What is an oxidising agent?
A substance which oxidised something else/gains electrons
what happens when you react zinc and copper sulfate solution?
The copper is displaced by the more reactive zinc. The blue copper solution fades as the colourless zinc solution is formed.
When does rusting occur?
When iron or steel react with oxygen and water.
Why will a bridge react faster if it close to the sea?
Salt speeds up the reaction.
What is a barrier method to prevent rusting?
Painting/oiling/greasing or covering iron in plastic, preventing oxygen or water from getting to it.
What is a sacrificial method to prevent rusting?
Metals that are more reactive than iron can be placed next to iron as they will react instead of iron, preventing the iron from rusting
What is an example of a sacrificial method to prevent iron from rusting?
Galvanising - coating iron with a layer of zinc. Zinc is more reactive than iron so it will react instead of the iron
What colour is litmus paper in acid?
Red
What colour is litmus paper in bases?
Blue
What colour is methyl orange in acid?
Red
What colour is methyl orange in a base?
Yellow
What colour is methyl orange in a neutral solution?
Yellow
What colour is phenolphthalein in acid?
Colourless
What colour is phenolphthalein in bases
Pink
What colour is phenolphthalein a neutral solution?
Colourless
What colour is universal indicator in acid?
Red
What colour is universal indicator in a base?
Blue
What colour is universal indicator in a neutral solution?
Green
How would you use a pH meter?
First adjust it to make sure the reading is accurate. Do this by putting it into a solution with a known pH and adjusting the reading until it gives the exact value.
What is an acid?
A source of H+ ions.
What is a base?
A source of OH- ions.
What does the pH scale range from?
0-14
What is a strong acid?
A strong acid has a high concentration of H+ ions.
What is a dilute acid?
One that contains more water than acid.
Which metals in the reactivity series react with dilute acid?
Everything above hydrogen
Common examples of acids:
Hydrochloric, sulphuric, nitric and ethanoic.
What is an alkali?
A base that dissolves in water.
Common alkalis:
Sodium hydroxide, calcium hydroxide and ammonia.
Metal + acid?
Salt + hydrogen
Metal + sulfuric acid
Metal sulfate + hydrogen
Acid + base
Salt and water
Acid + carbonate
Salt + water + carbon dioxide
Acid + metal oxide?
salt + water
Acid + metal hydroxide =
salt and water
What is the ionic equation for an acid + metal oxide reaction?
O2-(s) + 2H+(aq) → H2O(l)
what is the ionic equation for a metal hydroxide adding to a salt?
OH-(aq) + H+(aq) → H2O(l)
ionic equation for acid plus carbonate
CO32-(s) + 2H+(aq) → CO2(g) + H2O(l)
What is an exothermic reaction?
A reaction which releases thermal energy into its surroundings, meaning the surroundings increase in temperature.
Describe what it looks like when magnesium reacts with dilute sulfuric or hydrochloric acid:
Both reactions are similar. There is rapid fizzing and a colourless gas is evolved, which pops with a lit splint. The magnesium gradually disappears to leave a colourless magnesium chloride/sulfide solution.
Why are reactions with the same metal and different acids so similar?
Acids in solution are ionic. Hydrochloric acid contains hydrogen ions and chloride ions. Sulfuric acid contains hydrogen ions and sulfide ions. The hydrogen ions take part in the reaction but the sulfide and chloride ions are both spectator ions, i.e. remain unchanged just with a different partner.
Hydrochloric acid + calcium carbonate
Calcium chloride + water + carbon dioxide
What is neutralisation used in?
The neutralisation of sulphuric acid by ammonia is used to manufacture ammonium sulphate, an important fertiliser.
What is the ionic equation for the neutralisation of an acid and an alkali?
H+ + OH- = H2O
What is an endothermic reaction?
A reaction which absorbs thermal energy, and so causes a decrease in the temperature of the surroundings.
What is the formula for hydrochloric acid and what does it form?
HCl , forms salt chloride
What is the formula for sulphuric acid and what does it form?
H2SO4 , forms salt sulfate
What is the formula for nitric acid and what does it form?
HNO3 , forms salt nitrate
Why is the O2- ion not involved in the ionic equation?
It is unchanged in the reaction, it is just ends up with a different partner. It is known as a spectator ion.
Why is the O2- ion not involved in the ionic equation?
It is unchanged in the reaction, it is just ends up with a different partner. It is known as a spectator ion.
What is suck-back and why should you avoid it?
If you stop heating a test tube with a delivery tube under the surface of water, water is sucked back into the hot tube which could result in cracking. To avoid it heat it slowly and continuously until you remove the tube.
Are metal oxides acidic or basic?
they are basic oxides
what colour is zinc oxide?
white
What colour is iron oxide?
When iron reacts with steam a darker grey triiron tetraoxide is formed. Fe3O4
What colour is a copper solution?
blue
How would you go about making hydrogen in a lab?
from zinc and dilute sulfuric acid, with a very small amount of copper sulfate solution added to speed the reaction up.
What is the Bronsted-Lowry theory?
- An acid is a proton (hydrogen ion) donor
- A base is a proton (hydrogen ion) acceptor
What is hydrochloric acid?
A solution of hydrogen chloride gas dissolved in water. When HCl(g) dissolves in water, it reacts to give hydroxonium ions and chloride ions. The HCl dissociates.
What is the equation for the reaction of hydrogen chloride and water?
According to the Bronsted-Lowry theory, which is an acid and which is a base?
H2O(l) + HCl(g) → H3O+(aq) + Cl-(aq)
OR HCl(g) = H+(aq) + Cl-(aq) (EXOTHERMIC)
The HCl is the acid because it is giving a proton (hydrogen ion) to the water. The water is acting as a base because it accepts the hydrogen ion.
What is the H3O+(aq) ion?
It is called a hydroxonium ion but we normally just refer to it as H<span>+</span>
Describe the reaction of hydrogen chloride gas with ammonia gas?
(according to the Bronsted-Lowry theory) The ammonia acts (NH3) as a base by accepting the proton and the HCl acts as an acid by donating it. This time an ammonium ion (NH4+) is formed. There is a dative bond between the nitrogen and the new hydrogen ion.
What is the equation for the reaction of ammonia gas with hydrogen chloride gas?
What is the product?
NH3(g) + HCl(g) → NH4+(s) + Cl-(s)
The product is ammonium choride
What is the difference between hyrogen chloride and hydrochloric acid?
The are both HCl but hydrogen chloride is a covalent molecule which is a gas and hydrochloric acid is its solution in water.
How can you show that water reacts with hydrogen chloride gas?
Suspend a drop of water on a thermometer bulb and lower this into a gas jar of hydrogen chloride gas. There is a large increase of temperature showing that a reaction must have occured.
Does hydrogen chloride dissolve in methylbenzene?
Yes
Why does the hydrogen chloride to hydrochloric acid reaction not occur in methylbenzene (an organic solvent without oxygen)
HCl(g) does not disassociate because there is no proton acceptor or any H+ ions in the solution, so it will not have any acidic properties. This is why HCl is acidic in water but not in methylbenzene
This can be proved because it does not show simple acidic properties:
- it wont turn blue litmus paper red (providin the litmus paper is perfectly dry)
- it wont react with a magnesium ribbon to produce hydrogen
- it wont react with marble chips (calcium carbonate) to produce carbon dioxide
In what scenario would you do an acid-base titration?
For example, if you wanted to test out the concentration of an acid
Describe the method for an acid-base titration
1) wash out the burette with HCl, making sure the tap is closed
2) put a bulb on top of the pipette and empty the air out of the bulb
3) measure out 25cm3 of NaOH using the pipette into a concial flask
4) add 3 drops of indicator solution (e.g. phenolphthalein) into the NaOH. Make sure the flask is on a white tile
5) fill the burette with acid to the zero mark and take the initial reading. Read from the bottom of the meniscus and rpund the reading to 2dp to the nearest 0.05
6) first do the rough titration
7) add the acid into the conical flask 2cm3 at a time, swirling the flask (to get an accurate endpoint) until you reach 20cm3
8) then add the acid 0.5cm3 at a time, then drop by drop, until the acid just changes colour
In a redox reaction with halogens what do you NEED to remember?
if it’s a halogen ion i.e. with the negative charge say halide not halogen (e.g. bromide not bromine)
