Industrial Chemistry and Environmental Pollution Practice Flashcards

Practice flashcards covering G.C.E. (Advanced Level) Chemistry Unit 14, focused on industrial processes, chemical reactions, and environmental pollution as detailed in the National Institute of Education resource book.

What were the time periods identified for the first and second industrial revolutions?

The first industrial revolution occurred between 1750-1850 and the second occurred between 1870-1914 or 1850-1940.

What highly poisonous gas caused the death of about 8000 people during the Bhopal incident in 1984?

Methyl isocyanide.

What is the term for the solution discarded at the last stage of producing salt from sea water, which is rich in magnesium ions?

Bittern.

In Step 1 of the Dow process for magnesium extraction, what is the thermal decomposition reaction of limestone?

$$CaCO_3(s) \xrightarrow{\Delta} CaO(s) + CO_2(g)$$

During the electrolysis of fused $MgCl_2$ in the Dow process, why does molten magnesium float on the fused salt?

The density of molten Mg is $1.584\,g\,cm^{-3}$, which is lower than the density of fused $MgCl_2$ ($1.68\,g\,cm^{-3}$).

What are the three types of cells used to produce caustic soda by electrolysis?

Mercury cells, diaphragm cells, and membrane cells.

In the purification of brine for the membrane cell method, how are sulfate ions removed?

By adding adequate quantities of barium chloride to precipitate them as $BaSO_4(s)$.

What is the chemical composition of a soap molecule's hydrophilic head?

It contains a $Na^+$ or $K^+$ ion and the $-COO^-$ ionic group.

What is the 'TFM value' of soap and what is its typical range for washing soap?

TFM stands for Total Fatty Matter, representing the percentage of $RCOONa$; for washing soap, it is about $54-56\%$.

What are the primary chemical reactions involved in the Solvay process for producing sodium carbonate?

$NH_3 + H_2O \rightarrow NH_4OH$; $NH_4OH + CO_2 \rightarrow NH_4HCO_3$; $NaCl + NH_4HCO_3 \rightarrow NaHCO_3 + NH_4Cl$; $2NaHCO_3 \xrightarrow{\Delta} Na_2CO_3 + CO_2 + H_2O$.

Under what conditions is the Haber-Bosch process for ammonia production industrially conducted?

A temperature of $450-500\,^\circ\text{C}$, a pressure of $250-300\,atm$, an iron catalyst, and $K_2O$ and $Al_2O_3$ as catalytic promoters.

What catalyst is used in the Ostwald method for the production of nitric acid?

A $Pt/Rh$ catalyst.

In the Contact process for sulphuric acid, what catalyst and conditions are used to oxidize $SO_2$ to $SO_3$?

$V_2O_5(s)$ catalyst at $400-500\,^\circ\text{C}$ and $1\,atm$ pressure.

Why is $SO_3$ gas absorbed into concentrated sulphuric acid instead of water during the Contact process?

The reaction between $SO_3$ and water is violent and highly exothermic, producing a mist of sulphuric acid fumes.

What is the overall reaction for the chlorination step in the production of titanium dioxide from rutile?

$$TiO_2(s) + C(s) + 2Cl_2(g) \xrightarrow{950\,^\circ\text{C}} TiCl_4(g) + CO_2(g)$$

What substances form the 'slag' during iron extraction in a blast furnace?

Calcium silicate ($CaSiO_3(l)$) and calcium aluminate ($Ca(AlO_2)_2(l)$).

What is the chemical name and repeating unit structure of natural rubber?

Natural rubber is cis-1,4-polyisoprene.

What is the definition of vulcanization in rubber processing?

Vulcanization is the process of heating natural rubber with $1-3\%$ sulphur to form cross-links between polymer chains, increasing resilience.

According to Dalton's law of partial pressures, what is the boiling condition for an immiscible system of water and essential oil?

The system boils when the total pressure $P = P_{H_2O} + P_A$ equals the atmospheric pressure.

What reaction converts triglycerides in plant oils into fatty acid methyl esters (FAME) for biodiesel production?

Transesterification reaction.

What is the minimum pH value of rain water based on current atmospheric $CO_2$ composition (400 ppm)?

$$5.6$$

List five primary greenhouse gases mentioned in the text.

Water vapour ($H_2O$), Carbon dioxide ($CO_2$), Methane ($CH_4$), Nitrous oxide ($N_2O$), and Volatile halogenated hydrocarbons (CFC, HFC, HCFC).

What is the catalytic mechanism for ozone depletion involving chlorine free radicals ($\cdot Cl$)?

$\cdot Cl(g) + O_3(g) \rightarrow O_2(g) + \cdot OCl(g)$; $\cdot OCl(g) + \cdot O(g) \rightarrow O_2(g) + \cdot Cl(g)$. The $\cdot Cl$ radical is regenerated.

What two primary chemical pollutants and environmental conditions are required for photochemical smog?

Nitric oxide ($NO$), volatile hydrocarbons, sunlight, and a temperature above $15\,^\circ\text{C}$.

How is the chemical oxygen demand (COD) of a water sample determined in the laboratory?

By distilling the sample with acidified potassium dichromate and titrating the remaining dichromate with a standard $Fe^{2+}$ solution.

How is the dissolved oxygen (DO) level determined using the Winkler method?

Oxygen reacts with $Mn^{2+}$ in basic media to form $MnO_2$, which then reacts with iodide in acid to liberate $I_2$. The $I_2$ is titrated with standard thiosulphate: one mole of $O_2$ corresponds to four moles of $S_2O_3^{2-}$.

What is the definition of eutrophication?

The excessive growth of algae due to the addition of nutrients, such as phosphate or nitrate ions, to water.

Which plastic additive is used to make products more flexible but is also a known carcinogen that affects the endocrine system?

Phthalates (such as Dioctyl phthalate).