Acids and Alkalis Flashcards
What can solutions be?
Acidic, alkaline or neutral
Pure water is…
Neutral
What are two acids found at home?
Vinegar and Lemon Juice
What are two acids found in the lab?
Sulfuric acid and Hydrochloric acid
What are three alkalis found at home?
Baking soda, bleach and indigestion tablets
What are some alkalis found in the lab?
Sodium hydroxide and calcium hydroxide
If a substance has the word hydroxide in its name, what is it?
an alkali e.g potassium hydroxide
What can indicators be used to find out?
Whether a solution is acidic, alkaline or neutral by the colour they turn.
What can plant extracts be used as?
Indicators e.g red cabbage is a different colour in different solutions
What are universal indicator and pH paper?
Indicators
When does universal indicator and pH paper turn red?
In acidic solutions
What colour does universal indicator and pH paper turn in neutral solutions?
Green
When does universal indicator and pH paper turn blue?
In alkaline solutions
What can universal indicator/pH paper be used to find?
the pH of a solution
What does the pH scale measure?
how acidic or alkaline a solution is
The pH scale is a numbered scale going from 0 to…
14
What number is an acid on the pH scale?
pH=less than 7
What number is neutral on the pH scale?
pH=7
What number is an alkali on the pH scale?
pH=grater than 7
What pH value do very acidic solutions have?
the range from 0-2
What pH value do weakly acidic solutions have?
the range from 3-6
What pH value do very alkaline solutions have?
the range from 12-14
What pH value do weakly alkaline solutions have?
the range from 8-11
What does burning fossil fuels produce?
Carbon Dioxide
When an acid and alkali react with each other in equal volumes what happens?
they are neutralised and form a solution with pH=7
What happens when hydrochloric acid is neutralised using sodium hydroxide?
Sodium chloride (table salt) is made
How can solid salt be obtained?
by evaporating the salt solution
What is a use of neutralisation?
Indigestion (too much stomach acid) can be neutralised using magnesium hydroxide (milk of magnesia)
What is a use of neutralisation?
Wasp stings are alkaline and can be neutralised by using vinegar (acidic)
What is a use of neutralisation?
Bee stings are acidic and can be neutralised by using sodium bicarbonate (alkali) - acid soils an be treated with the alkali calcium hydroxide (known as lime).
What word equation can represent the neutralisation reaction between an acid and alkali?
acid+alkali ⇾ salt + water
What is an example of this reaction? (acid+alkali ⇾ salt + water)
Hydrochloric acid + sodium hydroxide⇾ sodium chloride + water
How can this word equation be represented in a symbol equation?
HCI + NaOH ⇾ NaCI + H2O
There are many different salts. Where does the metal part of the salt come from?
The alkali
Where does the non-metal part of the salt comes from?
the acid
What is a salt?
A compound made up of a metal and a non-metal part.
Describe the structure of an atom
An atom has a nucleus that contains protons and neutrons and the nucleus is surrounded by electrons in different shells.
How do you know the number of electrons in an atom?
the same number of protons (number of protons=number of electrons)
How can you find the number of neutrons in an atom?
the atomic mass - atomic number
What is a controlled variable?
The one that doesn’t change
What is an independent variable?
The one that is changed
What is a dependent variable?
The one that is measured
