AQA AS CHEMISTRY COMPREHENSIVE
EXAMINATION TEST 2026 QUESTIONS WITH
ANSWERS 100% CORRECT
◉ Give the formula for moles. [1] Answer: moles= mass÷Mr
◉ Give the formula for concentration in mol/dm³ [1] Answer:
concentration = moles÷volume
◉ State the Ideal Gas Equation, what each symbol represents and
the units for each symbol. [9] Answer: PV= nRT
where...
P= Pressure measured in Pa
V= Volume measured in m³
n= number of moles
R= The molar gas constant- 8.31JK^-1mol^-1
T= Temperatures measured in K
◉ Define Empirical Formula [1] Answer: The simplest whole-
number ratio of atoms of each element in a compound.
,◉ Define Molecular Formula [1] Answer: The actual number of
atoms of each element in a compound.
◉ Describe how to perform a titration. [5] Answer: 1. Fill a burette
with the acid of known concentration,
2. Accurately measure 25cm³ of the alkali solution using a pipette
and transfer it to a conical flask.
3. Add a few drops of a suitable indicator to the alkali. eg
phenolphthalein.
4. Slowly add the acid from the burette into the conical flask,
swirling constantly. As soon as the indicator changes colour the
solution has turned neutral so stop adding the acid.
5. Record the volume of acid added.
6. Repeat the process until you achieve concordant results. The
mean of these results is used to calculate the average titre.
◉ State the formula for percentage atom economy. [1] Answer:
◉ State the formula for percentage yield. [1] Answer:
◉ Describe how to make up a standard solution [7] Answer: 1.
Weigh the sample bottle containing the solid on a balance.
2. Transfer solid to a beaker and reweigh the sample bottle.
3. Record the difference in mass.
,4. Add distilled water and stir with a glass rod until the solid has
dissolved.
5. Transfer to a volumetric flask with washings.
6. Makeup to the 250cm³ mark with distilled water.
7. Shake flask.
◉ What is an ionic bond? [1] Answer: The strong electrostatic
attraction between oppositely charged ions.
◉ Describe the melting and boiling point of an ionic compound. [3]
Answer: - Strong electrostatic attraction between ions.
- This requires a lot of energy to overcome.
- Giving ionic compounds high melting and boiling points.
◉ Describe the electrical conductivity of an ionic compound. [3]
Answer: - Can conduct electricity when molten or in solution.
- When compound is solid the ions are held in fixed position and
cannot flow.
- When compound is molten/in solution, the ions are free to move
and carry charge.
◉ Describe the structural properties of an ionic compound. [2]
Answer: - Brittle, shatter easily.
, - As if the rows of ions slide past one another and like charges are
adjacent, the two fragments repel one another.
◉ What is meant by covalent bond? [1] Answer: A shared pair of
electrons between two atoms.
◉ Why do covalent substances not conduct electricity? [1] Answer:
Electrons used in forming covalent bonds and cannot carry charge.
◉ What is meant by coordinate bond? [1] Answer: A shared electron
pair which have both come from the same atom.
◉ When do coordinate bonds occur? [2] Answer: - One atom
requires at least two electrons in order to fill its outer shell, and is
electron deficient.
- One atom has a lone pair, which it donates.
◉ What is meant by metallic bonding? [1] Answer: The strong
electrostatic attraction of positive metal ions surrounded by a sea of
delocalised electrons.
◉ Why is the metallic bonding in magnesium stronger than in
sodium? [3] Answer: - Mg has a greater charge of 2+
- Mg has twice as many electrons in the sea of delocalised electrons
EXAMINATION TEST 2026 QUESTIONS WITH
ANSWERS 100% CORRECT
◉ Give the formula for moles. [1] Answer: moles= mass÷Mr
◉ Give the formula for concentration in mol/dm³ [1] Answer:
concentration = moles÷volume
◉ State the Ideal Gas Equation, what each symbol represents and
the units for each symbol. [9] Answer: PV= nRT
where...
P= Pressure measured in Pa
V= Volume measured in m³
n= number of moles
R= The molar gas constant- 8.31JK^-1mol^-1
T= Temperatures measured in K
◉ Define Empirical Formula [1] Answer: The simplest whole-
number ratio of atoms of each element in a compound.
,◉ Define Molecular Formula [1] Answer: The actual number of
atoms of each element in a compound.
◉ Describe how to perform a titration. [5] Answer: 1. Fill a burette
with the acid of known concentration,
2. Accurately measure 25cm³ of the alkali solution using a pipette
and transfer it to a conical flask.
3. Add a few drops of a suitable indicator to the alkali. eg
phenolphthalein.
4. Slowly add the acid from the burette into the conical flask,
swirling constantly. As soon as the indicator changes colour the
solution has turned neutral so stop adding the acid.
5. Record the volume of acid added.
6. Repeat the process until you achieve concordant results. The
mean of these results is used to calculate the average titre.
◉ State the formula for percentage atom economy. [1] Answer:
◉ State the formula for percentage yield. [1] Answer:
◉ Describe how to make up a standard solution [7] Answer: 1.
Weigh the sample bottle containing the solid on a balance.
2. Transfer solid to a beaker and reweigh the sample bottle.
3. Record the difference in mass.
,4. Add distilled water and stir with a glass rod until the solid has
dissolved.
5. Transfer to a volumetric flask with washings.
6. Makeup to the 250cm³ mark with distilled water.
7. Shake flask.
◉ What is an ionic bond? [1] Answer: The strong electrostatic
attraction between oppositely charged ions.
◉ Describe the melting and boiling point of an ionic compound. [3]
Answer: - Strong electrostatic attraction between ions.
- This requires a lot of energy to overcome.
- Giving ionic compounds high melting and boiling points.
◉ Describe the electrical conductivity of an ionic compound. [3]
Answer: - Can conduct electricity when molten or in solution.
- When compound is solid the ions are held in fixed position and
cannot flow.
- When compound is molten/in solution, the ions are free to move
and carry charge.
◉ Describe the structural properties of an ionic compound. [2]
Answer: - Brittle, shatter easily.
, - As if the rows of ions slide past one another and like charges are
adjacent, the two fragments repel one another.
◉ What is meant by covalent bond? [1] Answer: A shared pair of
electrons between two atoms.
◉ Why do covalent substances not conduct electricity? [1] Answer:
Electrons used in forming covalent bonds and cannot carry charge.
◉ What is meant by coordinate bond? [1] Answer: A shared electron
pair which have both come from the same atom.
◉ When do coordinate bonds occur? [2] Answer: - One atom
requires at least two electrons in order to fill its outer shell, and is
electron deficient.
- One atom has a lone pair, which it donates.
◉ What is meant by metallic bonding? [1] Answer: The strong
electrostatic attraction of positive metal ions surrounded by a sea of
delocalised electrons.
◉ Why is the metallic bonding in magnesium stronger than in
sodium? [3] Answer: - Mg has a greater charge of 2+
- Mg has twice as many electrons in the sea of delocalised electrons
