Acids and Bases Flashcards
What is the pH scale?
The pH scale is a measure of how acid or alkaline a solution is.
What does the lower of the pH solution means?
The lower pH of a solution, the more acidic it is.
What does the higher of the pH solution means?
The higher the pH of a solution, the more alkaline it is.
What is a neutral substance?
A neutral substance (e.g. pure water) has pH 7.
What is an indicator?
An indicator is a dye that change colour depending on whether it’s above or below a certain pH.
What are wide range indicators?
Some indicators contain a mixture of dyes that means they gradualy change colour over a broad rang of pH. THese are called wide range indicators and they’re useful for estimating the pH of a solution. For example, universal indicator gives the colours shown above.
What is a pH probe attached to a pH meter?
A pH probe attached to a pH meter can also be used to measure pH electronically. The probe is placed in the solution you are measuring and the pH is given on a digital dislay as a numerical value, meaning it’s more accurate than an indicator.
What is an acid and what does it forms?
An acid is a substance that forms aqueous solutions with a pH of less than 7. Acids form H+ ions in water.
What is a base.
A base is a substance with a pH greater than 7.
What is a alkali and what does it forms?
An alkali is a base that dissolves in water to form a solution with a pH greater than 7. Alkalis form OH- ions in water.
What is neutralisation?
Is the reaction between acids and bases. Acid + base → salt + water.
Describe neutralisation between acids and alkalis.
Neutralisation between acids and alkalis can be seen in trms of H+ and OH- ions ike: H+(aq) + OH-(aq) → H₂O (l).
What happens when an acid neutralises a base (or vise verse)? What can be used to show it?
When an acid neutralises a base (or vise versa), the product are neutral, i.e. they have a pH of 7. An indicator can be used to show that a neutralisatin reaction is over.
