How many QCAA Chemistry questions cover Chemical synthesis and design?

AusGrader has 109 QCAA Chemistry questions on Chemical synthesis and design, all with instant AI grading and detailed marking feedback.

QCAA (QCE) Chemistry — Chemical synthesis and design Questions & Answers | AusGrader

Q12

2023

QCAA

Paper 1

1 mark

Q12

1 mark

Enzymes are classified as

A

carbohydrates.

B

proteins.

C

starches.

D

lipids.

Q19

2021

QCAA

Paper 1

1 mark

Q19

1 mark

To form ethanol biofuel in the fermentation of glucose, a catalyst is used because

A

less energy is required and the rate of reaction is increased.

B

less energy is required and the rate of reaction is decreased.

C

more energy is required and the rate of reaction is increased.

D

more energy is required and the rate of reaction is decreased.

Q25

2023

QCAA

Paper 1

7 marks

Q25

During the contact process for manufacturing sulfuric acid, sulfur dioxide ( $\text{SO}_2$ ) and oxygen ( $\text{O}_2$ ) are passed over a vanadium oxide catalyst to produce sulfur trioxide ( $\text{SO}_3$ ). In the process, the vanadium oxide undergoes the following reactions.

Reaction 1: $\text{SO}_2\text{(g)} + \text{V}_2\text{O}_5\text{(s)} \rightarrow \text{SO}_3\text{(g)} + \text{V}_2\text{O}_4\text{(s)}$
Reaction 2: $2\text{V}_2\text{O}_4\text{(s)} + \text{O}_2\text{(g)} \rightarrow 2\text{V}_2\text{O}_5\text{(s)}$
Overall reaction: $2\text{SO}_2\text{(g)} + \text{O}_2\text{(g)} \xrightarrow{\text{V}_2\text{O}_5\text{(s)}} 2\text{SO}_3\text{(g)}$

Q25a

1 mark

Determine the oxidation state of vanadium in $\text{V}_2\text{O}_4\text{(s)}$ .

Descriptor	Marks
determines that the oxidation state of vanadium is +4	1

Q25b

2 marks

Determine if vanadium in $\text{V}_2\text{O}_5\text{(s)}$ in reaction 1 is acting as an oxidising or reducing agent. Explain your reasoning.

Vanadium in $V_2O_5(s)$ is acting as an oxidising agent in reaction 1 as the oxidation state decreased from +5 to +4 in $V_2O_4(s)$ .

Marking Criteria

Descriptor	Marks
determines that vanadium in $V_2O_5(s)$ is an oxidising agent	1
explains that oxidation state of vanadium decreases from +5 to +4	1

Q25c

4 marks

Use the reactions provided to explain why $\text{V}_2\text{O}_5\text{(s)}$ is a catalyst for the overall reaction.

Reaction 1: $V_2O_5(s)$ is converted to $V_2O_4(s)$ to allow $SO_2$ to be converted to $SO_3$ .
Reaction 2: $V_2O_4(s)$ is converted back to $V_2O_5(s)$ by reacting with $O_2$ .
Therefore, $V_2O_5(s)$ acts as a catalyst because it undergoes a temporary chemical change during the reaction but remains chemically unchanged at the end.

Marking Criteria

Descriptor	Marks
identifies that $V_2O_5(s)$ is involved in the chemical reaction	1
uses data from reaction 1 to support chemical change to $V_2O_4(s)$	1
uses data from reaction 2 to support chemical change to $V_2O_5(s)$	1
explains that $V_2O_5(s)$ remains unchanged at the end of the reaction	1

Q22

2024

QCAA

Paper 1

3 marks

Q22a

2 marks

Describe the type of reaction that occurs when amino acid monomers are joined to form polypeptides.

A condensation reaction occurs when amino acid monomers are joined to form a peptide bond and water is removed.

Marking Criteria

Descriptor	Marks
Identifies condensation reaction	1
Describes that water is removed when the amino acids are joined to form polypeptides	1

Q22b

1 mark

Identify the bond formed when amino acid monomers join to form a dipeptide.

Descriptor	Marks
Identifies peptide bond	1

Q3

2020

QCAA

Paper 2

9 marks

Q3

Ethanol can be produced by the fermentation of glucose or the hydration of ethene.

Q3a

3 marks

Describe the production of ethanol by fermentation of glucose by writing a balanced equation and indicating if a catalyst is required.

C $_6$ H $_{12}$ O $_6$ (aq) $\xrightarrow{\text{yeast}}$ 2CH $_3$ CH $_2$ OH(aq) + 2CO $_2$ (g)

Marking Criteria

Descriptor	Marks
provides correct reactants and products	1
correctly balances the equation	1
indicates that yeast is required as a catalyst	1

Q3b

2 marks

Calculate the atom economy for the production of ethanol by fermentation of glucose.

Molar mass (ethanol) = 46.08 g
Molar mass (glucose) = 180.18 g
atom economy = $\frac{2 \times 46.08}{180.18} \times 100$

atom economy = $\frac{2 \times 46.08}{180.18} \times 100 = 51.148 \% \approx 51\%$
Atom economy = 51%

Marking Criteria

Descriptor	Marks
shows substitution correctly performed	1
determines atom economy	1

Q3c

2 marks

In terms of atom economy, determine which process for the production of ethanol (i.e. hydration of ethene or fermentation of glucose) is greener.

Hydration atom economy = 100%
Fermentation atom economy = 51%
Therefore, production of ethene by hydration is greener.

Marking Criteria

Descriptor	Marks
determines atom economy for hydration reaction is 100%	1
identifies that hydration reaction is greener	1

Q3d

2 marks

Identify two principles of green chemistry, other than atom economy, that make the production of ethanol by fermentation greener than by hydration.

QCAA Chemistry Chemical synthesis and design

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Descriptor	Marks
provides use of renewable feedstocks	1
provides design for energy efficiency	1