Acids & Bases Flashcards
Give the equation of the dissociation of water molecules.
H₂O ⇌ H⁺ + OH⁻
How do you name a salt?
The 1st part of the name comes from the 1st part of the base.
The 2nd part of the name comes from the type of acid. Eg: hydrochloric acid = chloride,
nitric acid = nitrate, phosphoric acid = phosphate, sulfuric acid = sulfate
Eg: copper oxide + nitric acid → copper nitrate + water
What does ⇌ mean?
⇌ means that a reaction is reversible.
Why is water a neutral substance?
Water is a neutral substance because it has an equal concentration of H⁺ and OH⁻ ions.
How you do carry out volumetric titration?
It involves reacting an acid with a base.
What three groups do chemicals fall under (in terms of pH)?
- neutral
- acidic
- basic
What is a standard solution?
A solution of accurately known concentration.
What makes substances acidic?
Acidic substances have a higher concentration of H⁺ ions to OH⁻ ions.
What is the definition of concentration?
Concentration is the measure of the amount of solute dissolved in a certain volume of solvent. It is measured in mol/l.
What is the formula for concentration?
n=cV
n = number of moles
c = concentration (mol/l)
V = volume (litres) (VOLUME MUST BE IN LITRES, TO CHANGE FROM CM3, DIVIDE BY 1000)
What makes substances basic?
Basic substances have a higher concentration of OH⁻ ions to H⁺ ions.
How can we tell acidic, basic and neutral substances apart?
We can use an indicator. An indicator is a chemical which changes colour depending on the acidity of what is being tested.
(examples include: red cabbage, universal indicator, pH paper)
Example calculation: Calculate the mass of NaOH which is needed to make 200cm3 of a 4 mol/l solution.
Step 1: Calulate number of moles
n=cV
n= 4x0.2
n= 0.8 moles
Step 2: calculate mass
m=nxGFM
m= 0.8x40
m= 32g
The mass of NaOH is 32g
What are the names of common acids?
- hydrochloric acid: HCl / H⁺Cl⁻
- sulfuric acid: H₂SO₄ / (H⁺)₂SO₄²⁻
- nitric acid: HNO₃ / H⁺NO₃⁻
- phosphoric acid: H₃PO₄ / (H⁺)₃PO₄³⁻
- citric acid
- ascorbic acid (vitamin C)
What are the steps of a titration calculation?
- Calculate the number of moles (n) using n=cV for the reactant whose concentration and volume is given.
- Use mole ratio to find the number of moles of the other reactant.
- Calculate the unknown (either c or V) using either c=n/V or V=n/c