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Edexcel GCSE Chemistry
Topic 3: Chemical Changes
3.1 Acids and Alkalis
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Cards (78)
What color does litmus paper turn in alkaline conditions?
Blue
Acids have a pH less than
7
Acids have a pH less than 7, indicating they are
acidic
What color does litmus paper turn in alkaline conditions?
Blue
What is the taste of alkalis?
Bitter
What ions do strong alkalis produce in water?
Hydroxide ions (OH-)
What reaction occurs when acids interact with metals?
Hydrogen gas production
What happens to litmus paper when exposed to acids?
Turns red
What is the pH range for acids?
Less than 7
What is the pH range for alkalis?
Greater than 7
Alkalis produce hydrogen gas when reacted with metals.
False
What is considered a neutral pH on the pH scale?
7
Match the indicator with its color in acidic conditions:
Litmus paper ↔️ Red
Phenolphthalein ↔️ Colorless
Universal indicator ↔️ Red/orange
Indicators undergo a chemical reaction to change color based on
pH
.
True
When HCl reacts with NaOH, the products are NaCl and
H2O
.
True
During neutralization, acidic and
alkaline
properties are neutralized.
True
Acids have a pH less than 7, while alkalis have a pH greater than 7.
True
Acids are used to lower
pH
in swimming pools and aquariums.
True
What gas is produced when acids react with metals?
Hydrogen gas
What is the pH of a neutral substance?
7
Strong acids have a high pH and low conductivity.
False
Each whole number on the pH scale represents a tenfold difference in hydrogen ion concentration.
True
Match the pH range with its category:
0 to < 7 ↔️ Acidic
7 ↔️ Neutral
> 7 to 14 ↔️ Alkaline
Indicators change color at different
pH
values.
True
Alkalis have a
pH
greater than 7.
True
Acids have a bitter taste.
False
Alkalis have a pH greater than
7
Acids turn litmus paper
red
Weak acids and weak alkalis only partially
dissociate
Alkalis have a pH greater than 7 and a
bitter
Alkalis
have a pH
greater
than
7
Acids have a
sour
taste
Alkalis have a
bitter
taste
Match the type of acid/alkali with its ion concentration:
Strong acid ↔️ High concentration of H+ ions
Weak acid ↔️ Low concentration of H+ ions
Strong alkali ↔️ High concentration of OH- ions
Weak alkali ↔️ Low concentration of OH- ions
Weak acids have a very low pH.
False
Lemon juice, with a pH of 2, is an example of an
acidic
Litmus paper turns blue in
alkaline
conditions
What two products are formed in a neutralization reaction?
Salt and water
What are the pH values of acids and alkalis in a neutralization reaction?
Less than 7 and greater than 7
A neutralization reaction occurs when an acid and an alkali react to form a
salt
and
water
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