Topic 3 - Chemical Changes (Year 10) Flashcards
What ion is produces by all alkalis in aqueous solutions?
OH-
What ion is produces by all acidic in aqueous solutions?
H+
Whatis the pH of a neutral solution?
7
Whatis the pH of an alkaline solution?
Anything above 7
Whatis the pH of a acidic solution?
Anything below 7
True or False: Alkalis have a pH of more than 7?
True, remember a neutral solution has a pH of exactly 7
What type of reaction occure when hydrochloric acid reacts with the potassium hydroxide?
Neutralisation
Complete the equation: Acid + Alkali →
Salt + Water
Complete the equation: Hydrochloric acid + Potassium hydroxide →
Potassium Chloride + Water
Define the term: Indicator
a compound that changes colour at a specific pH value or in the presence of a particular substance
Methy orange truns red in the presence of what solution?
An acidic Solution
Phenolphthalein turns pink in the presences of what solution?
Alkaline solution
Phenolphthalein turns colourless in the presences of what solution?
Acidic solution
Complete the equation: H+ + OH- →
H2O
What is the formula for hydrochloric acid?
HCl
What is the formula for sulfuric acid?
H2SO4
What is the formula for nitric acid?
HNO3
Define the term: Ionisation
The splitting up of a compound into separate smaller ions
What is the equation for the dissociation of Hydrochloric Acid (HCl)?
HCl → H+ + Cl-
Define the term: Concentration
Relative amount of a particular substance contained within a solution or mixture or in a particular volume.
Define the term: Alkali
A solution with a pH of more than 7 and that contains an excess of hydroxide (OH–) ions.
Define the term: Base
Any substance, soluble or insoluble, that neutralises an acid, forming a salt and water only.
Define the term: Soluble
Soluble means something that will dissolve
Define the term: Insoluble
Insoluble means something that will not dissolve
Explain the difference between an alkali and a base
A base is a chemical which will react with an acid to form a salt and water only. An alkali is a water-soluble base.
What will be produced if sulfuric acid reacts with a metal?
Metal sulfate and hydrogen
Name the products of the reaction between sulfuric acid and copper oxide
Copper Sulfate and water
Explain how you could make copper sulfate (A soluble salt from an insoluble base)?
- Gently heat the acid.
- Add insoluble base (Copper Oxide).
- Filter off excess insoluble base.
- Eveporate off excess water to leave crystals
Complete the equation: Acid + Metal Oxide →
Salt + Water
Complete the equation: Acid + Metal →
Salt + Hydrogen
Complete the equation: Acid + Metal Carbonate →
Salt + Water + Carbon Dioxide
How do you test for hydrogen?
Take a light splint and place it into a tube containing the gas, it should produce a squeaky pop (Squeaky Pop Test)
How do you test for Carbon Dioxide?
Bubble the gas through lime water. The lime water will go from clear to cloudy
True or False: Sodium Nitrate is soluble?
True, all nitrates are soluble
True or False: Magnesium chloride is insoluble?
False: common chlorides are soluble except those of silver and lead
True or False: Barium Carbonate is insoluble?
True, common carbonates and hydroxides are insoluble except those of sodium, potassium and ammonium
True or False: Calcium Sulfate is insoluble?
False, common sulfates are soluble except those of lead, barium and calcium
True or False: Potassium Chloride is soluble?
True, all. Common sodium, potassium and ammonium salts are soluble
True or False: Precipitation reactions can be used to make insoluble salts by mixing an insoluble salt with a soluble salt?
False, Precipitation reactions occur between two soluble salts to form an insoluble salt
How do you make an insoluble salt?
- Mix two insoluble salts together that produce a precipitate.
- Filter off the unwanted solution.
- Dry the remaining salt retained through filtration
Why would we use a titration?
To react accurately, exact amounts of an acid and an alkali together.
How do you carry out a titration?
- Add acid into a beaker and alkali into your burette.
- Check the pH of your acid.
- Add the akali dropwise, constantly checking the pH, until you get a neutral solution
Write the equation for the dissociation of HCl
H+ + Cl-
Write the equation for the dissociation of H2SO4
2H+ + SO42-
Write the equation for the dissociation of HNO3
H+ + NO3-
What is the formula for a nitrate ion?
NO3-
What is the formula for a sulfate ion?
SO42-
What is the formula for a chloride ion?
Cl-
How does an indicator show the acidity or alkalinity of solutions?
by changing colour
What happens in all chemical reactions?
new substances are formed
Which ion is in excess in all acidic solutions?
hydrogen ions or H+ ions
What is meant by a strong acid?
An acid that fully dissociates
What is meant by a weak acid?
An acid that only partly dissociates
What is a more accurate methof of testing pH?
pH probe - give an exact reading of the pH of a solutionn
Give a disadvantage of Universal indicator
Due to it beinng a scale can be hard to tell the pH exactly
What word describes a solution that contains a large amount of solute in a small volume of solvent?
concentrated
What name is given to substances that react with acids to form a salt and water only?
bases (bases are metal oxides and hydroxides, soluble bases are alkalis)
What colour is phenolphthalein in acidic solutions?
colourless – not ‘clear’
Name a piece of apparatus used to measure volumes of liquid.
measuring cylinder/pipette/burette
What is seen when magnesium is added to dilute sulfuric acid?
effervescence/fizzing/bubbles (yes you know this is hydrogen, but you can not see that!!)
How do you test for oxygen?
Get a boiling tube of the gas, place in a glowing splint, the splinnnt will relight
How do you test for chlorine?
Damp blue litmus paper bleaches/goes white
Why do you heat the acid when making copper sulfate?
Speed up rate of reaction
When making copper sulfate you add copper oxide to heated sulfuric acid. Why is copper oxide added in excess?
To make sure that all acid has been reacted - makes the crystallisation step safer
