Chapter 4 Acids and Redox Flashcards
What do all acids contain?
hydrogen -> release H+ ions into the solution when dissolved in water
Strong acid
Releases all its hydrogen atoms into solution as H+ ions and completely dissociates in aqueous solution
Weak acid
- Releases a small proportion of its available hydrogen atoms into solution as H+ ions
- Partially dissociates in aqueous solution
Example of a strong acid
hydrochloric acid
Example of a weak acid
Ethanoic acid -> only releases the H on the COOH group
Bases
A substance which readily accepts H+ ions
Examples of bases
- Metal oxide
- Metal hydroxides
- Metal carbonates
Alkali
- A soluble base
- Dissolves in water, releasing OH- ions into the solution
Neutralisation
- When the H+ ions (of an acid) react with a base to form a salt and neutral water
- The H+ ions from the acid are replaced by metal or ammonium ions from the base
Equations
- Metal + acid -> salt + hydrogen
- Alkali + acid -> water + salt
- Base + acid -> water + salt
- Carbonate + acid -> Water + carbon dioxide + salt
Titration
A technique used to accurately measure the volume of 1 solution that reacts exactly with another solution
What can titrations be used for?
- Finding the concentration of a solution
- Identification of unknown chemicals
- Finding the purity of a substance
Volumetric flask
Used to make up a standard solution very accurately
- come in different sizes
Process of preparing a standard solution
- The solid is weighed accurately
- Solid is dissolved in a break using a little distilled water
- This solution is transferred to a volumetric flask
- The last traces of the solution is rinsed with distilled water
- The flask is filled up to the graduation line (bottom of meniscus) on the volumetric flask with distilled water
- The volumetric flask is slowly inverted several times to mix the solution thoroughly
What would happen if you didn’t invert the volumetric flask
- Titration results would be inconsistent