Topic 4 Acids and alkalis Flashcards
1
Q
- What term describes a substance that attacks metals, stonework and skin?
A
corrosive
2
Q
- Name an acidic solution found in the kitchen.
A
vinegar or fruit juice, etc.
3
Q
- Name an alkaline solution used in the kitchen.
A
bleach or oven cleaner or soap, etc.
4
Q
- What type of substance turns litmus paper red?
A
acid
5
Q
- How does an indicator show the acidity or alkalinity of solutions?
A
by changing colour
6
Q
- What pH values represent alkaline solutions?
A
above 7 or 8 to 14
7
Q
- What happens in all chemical reactions?
A
new substances are formed
8
Q
- What kind of reaction occurs between an acid and an alkali?
A
neutralisation
9
Q
- What do you call a solution that is neither acidic nor alkaline.
A
neutral
10
Q
- Give the name and formula of a common laboratory acid.
A
hydrochloric acid (HCl) or nitric acid (HNO3) or sulfuric acid (H2SO4), etc.
11
Q
- Which ion is in excess in all acidic solutions?
A
hydrogen ions or H+ ions
12
Q
- Which ion is in excess in all alkaline solutions?
A
hydroxide ions or OH– ions
13
Q
- What scale is used for measuring acidic and alkaline properties?
A
the pH scale
14
Q
- Name three examples of acid/alkali indicators apart from universal indicator.
A
litmus, methyl orange and phenolphthalein
15
Q
- What would you use to measure pH to one decimal place?
A
a pH meter
16
Q
- What pH values are acidic?
A
below 7
17
Q
- What colour is phenolphthalein in a solution with a pH of 2?
A
colourless
18
Q
- What happens to the pH as the H+ ion concentration increases?
A
it decreases
19
Q
- If a solution has the same concentration of hydrogen ions as hydroxide ions, how is it described?
A
neutral or pH = 7
20
Q
- If 2 g of salt is dissolved in 250 cm3 of solution, what is its concentration in g dm–3?
A
8 g dm–3
21
Q
- What word describes a solution that contains a large amount of solute in a small volume of solvent?
A
concentrated
22
Q
- How can a solution be made more dilute?
A
by adding solvent/water
23
Q
- If 24 g of acid is dissolved in 600 cm3 of solution, what is its concentration in g dm–3?
A
40 g dm–3
24
Q
- What happens when strong acid molecules dissolve in water?
A
they dissociate completely into ions
25
Q
- What kind of reaction occurs between an acid and a base?
A
neutralisation
26
Q
- What happens to the pH of an acid as it reacts with a neutraliser?
A
pH increases
27
Q
- What is formed when an acid reacts with a base like a metal oxide?
A
salt + water
28
Q
- What acid would be used to make zinc sulfate from zinc oxide?
A
sulfuric acid (sulphuric acid makes sulphates!)