Question 1

Which of the following best describes the main disadvantage of conventional solid-state reactions for synthesizing solids?

Accepted Answer

Diffusion through the lattice is slow, making the reactions intrinsically slow.

Question 2

In the synthesis of ferroelectric BaTiO$$_3$$, which reaction occurs during the solid-state process?

Accepted Answer

$$\mathrm{$$BaCO_3$$(s) + $$TiO_2$$(s) \rightarrow $$BaTiO_3$$ + CO_2$(g)}$$

Question 3

Which property makes mechanosynthesis potentially 'green' compared to conventional solid-state synthesis?

Accepted Answer

It requires little or no solvent and less energy.

Question 4

Combustion synthesis is also known as self-propagating high-temperature synthesis (SHS). What is the main advantage of this method?

Accepted Answer

The reaction propagates rapidly, often in minutes or seconds.

Question 5

Which of the following is a real-world application of BaTiO$$_3$$ produced by solid-state reaction?

Accepted Answer

Multilayer capacitors

Question 6

During the calcination of cement, which reaction is responsible for the release of CO$$_2$$?

Accepted Answer

$$\mathrm{$$CaCO_3$$ \rightarrow CaO + CO_2$}$$

Question 7

Which structure is associated with the rock salt form of CaO?

Accepted Answer

Rock salt

Question 8

Which process is used commercially for the purification of nickel, involving a volatile intermediate?

Accepted Answer

Mond process

Question 9

Flame synthesis (flame spray pyrolysis) is used on a massive scale for which material, commonly used as a pigment and conductive filler?

Accepted Answer

Carbon black

Question 10

Which equation represents the chloride process for producing high-quality rutile (TiO$$_2) $$via flame synthesis?

Accepted Answer

$$\mathrm{$$TiCl_4$$ + O_2$ \rightarrow $$TiO_2$$ + 2Cl_2}$$

Question 11

Which thin film deposition method uses atomic or ionic vapour sources and condenses them onto a substrate?

Accepted Answer

Physical Vapour Deposition (PVD)

Question 12

Metal Organic Chemical Vapour Deposition (MOCVD) is used to produce GaN for LEDs. Which reaction represents the multi-source method?

Accepted Answer

$$\mathrm{Me_3Ga + NH_3$ \rightarrow GaN + 3CH_4}$$

Question 13

Which of the following is a key societal challenge addressed by improvements in materials chemistry?

Accepted Answer

Achieving a sustainable future

Question 14

Which method is most suitable for producing highly crystalline thin films with atomic precision for applications such as touch screens?

Accepted Answer

Physical Vapour Deposition (PVD)

Question 15

Which process is used to accelerate transport rates in dry systems by creating a vapour concentration gradient in a sealed tube?

Accepted Answer

Vapour transport / sealed tube reactions

Question 16

Which of the following is a risk associated with mechanosynthesis using ball milling?

Accepted Answer

Contamination by ball-milling media

Question 17

Which of the following is a key property of Ni$$_{0.5}Zn$_{0.5}Fe$_2O$_4$$ produced by combustion synthesis, making it suitable for transformer cores?

Accepted Answer

Soft magnetism with high resistance

Question 18

Which equation represents the equilibrium in the Van Arkel purification process for chromium?

Accepted Answer

$$\mathrm{Cr + I_2$ \rightleftharpoons $$CrI_2$$ (g)}$$

Question 19

Which method is used to produce carbon black, a material used in tyres and battery electrodes, on a massive scale?

Accepted Answer

Flame synthesis (flame spray pyrolysis)

Synthesis of Solids: Dry Methods in Materials Chemistry

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