Reactions In Water Flashcards
What are the properties of bases? (8)
- Tastes bitter
- Turns litmus paper blue
- Feels slippery
- Reacts with acids to produce salt and water
- Generally ionic substances
- Usually insoluble in water
- Can be corrosive
- Are electrolytes
What are the properties of acids? (5)
- Usually taste sour
- Corrosive
- Molecular in structure and dissolve in water to produce and electrolyte
- Turn litmus paper red
- React with bases to produce salt and water
Name 4 acids, their formula and a use.
- Nitric: HNO3- fertilisers
- Hydrochloric acid: HCl- clean bricks
- Sulfuric acid: H2SO4- detergents
- Sodium hydroxide: NaOH- manufacture of soap
- What are the products of an acid + metal (not ag, cu or hg)?
Salt and hydrogen gas
- What are the products of an acid + metal carbonate? (3)
Salt + carbon dioxide + water
- What are the products of an acid + metal hydrogen carbonate? (3)
Salt + carbon dioxide + water
- What are the products of an acid + metal sulfite? (3)
Salt + Sulfur dioxide + water
- What are the products of an acid + metal sulfide? (2)
Salt + hydrogen sulfide gas
- What are the products of an acid + metal oxide? (2)
Salt + water
- neutralisation
- What are the products of an acid + metal hydroxide (base)?
Neutralisation
Salt + water
What does the Brønsted- Lowry theory state about acids and bases?
- an acid is a substance that donate a proton (h+ ion) to another substance
- a base is a substance that accepts a proton (h+ ion) from another substance
What is a conjugate pair?
A conjure acid- base pair is are 2 species that differ by one proton.
Eg. HNO3 –> NO3 are a conjugate pair
- the base is the one that accepts the proton
- the acid is the one the donates the proton
What is Arrhenius’s theory?
- acids produce H3O+ in water
- bases produce OH- in water
What is ionisation?
A reaction in which a substance reacts with water to produce ions.
These substance can be acids but not bases.
What is hydrolysis?
A reaction in which one substance reacts with water to form OH- or H3O+.
Hydrolysis can also be called ionisation.
What is dissociation?
When a substance dissolves into its individual constituents. They do not ionise because they do not react with water to produce ions.
These substance can be bases but not acids.
What is a neutralisation reaction?
Neutralisation is the process of an acid reacting with a base. The acid and base properties can be cancelled out if the exact amounts of both are used. A neutralisation reaction produces a salt and water as its products.
What is a polyprotic acid? What are the different types? (3)
When an acid can donate more than one proton per molecule of acid.
Monoprotic- donates one proton
Diprotic- donates two protons
Triporotic- donates three protons
These reactions must be written as different stages depending on how many protons it can donates.
What is a amphiprotic substance?
A substance that can act as an acid or bases according to their chemical environment. They can donate/ accept protons.
Eg water
Why can Water self ionise?
Water can self ionise because it can act as an acid or a base and can therefore react with itself.
Water is neutral at 10^-7 concentration of its ions (25 degrees).
The concentration of H3O+ and OH- will always equal 14 when added together.
How are the strengths of acids and bases measured?
Base: how readily it accepts protons eg O2
Acid: how readily it donates protons and completely ionises in water eg HCl
Acids and bases can be strong or weak
What is the difference between the concentration and strength of an acid or base?
The strength is determined by its ability to donate/ accept a proton whereas concentration refers to the amount of acid or base in a given amount of solution. Either dilute or concentrated.
What is the PH scale?
A logarithmic scale that indicates the acidity of a solution by determining the concentration of hydromium ions.
- 7 is neutral
- less then 7 is an acid
- more then 7 is a base
What is the formula for determining the PH?
- log10 [H3O+]
How to calculate the ph when dilution is in effect?
Use the equation C1xV1 = C2xV2
Fill in the blanks and solve to find the unknown. Then add in to log on calc.
How to find the ph of a base?
Follow the steps for finding the concentration of [H3O+] using log on calc.
Then subtract that ph from 14.
How is a hydronium ion produced?
When an acid donates its proton in water a hydronium ion is produced as a proton, H+, cannot exist by itself as it is attracted to the negative end of the polar water molecule to form a hydronium ion, H3O+.
Explain why a neutral solution has a ph of 7?
At 25 °C, [H3O+] × [OH–] = 10^–14. In a neutral solution, [H3O+] must equal [OH–] which has a concentration of 10^–7 M.
What is a characteristic of an acid base reaction?
A transfer of a proton H+
What determines if a hydrogen bonded to another atom is a proton?
If the hydrogen atom is bonded to a very electronegative atom. This means that hydrogens atoms electrons will be closer to the other atom and hydrogen will virtually just be a proton, allowing it to be lost easily..
Why are polyprotic acids not a strong?
After its first ionisation, the acid will be left with a negative charge. A negative charge will attract protons, making it harder for it to act as an acid.
What is the acidity constant?
It gives a measure for the strength of an acid. The higher the constant the higher the strength of the acid.
