Provide four differences between NaCl and C6H12O6, list four fundamental units of measurement and their symbols, define a derived unit, and list two examples of worms that infest cattle and two precau

Here are the solutions to all the questions:

1 (ii) Write down four differences between NaCl and C$_6$H$_{12}$O$_6$.

• NaCl is an ionic compound, while C$_6$H$_{12}$O$_6$ (glucose) is a covalent compound.
• NaCl has a high melting point (801 °C), while C$_6$H$_{12}$O$_6$ has a lower melting point (146 °C).
• NaCl conducts electricity when molten or dissolved in water, while C$_6$H$_{12}$O$_6$ does not conduct electricity.
• NaCl is an inorganic compound, while C$_6$H$_{12}$O$_6$ is an organic compound.

1 (c) (i) State four fundamental units of measurement and their symbols.

• Length: meter (m)
• Mass: kilogram (kg)
• Time: second (s)
• Electric current: ampere (A)

1 (c) (ii) What is a derived unit?
A derived unit is a unit of measurement that is obtained by multiplying or dividing fundamental (base) units of the International System of Units (SI). Examples include square meter (m$^2$) for area or meter per second (m/s) for speed.

1 (d) (i) List two examples of worms that infest cattle.

• Tapeworms
• Roundworms (e.g., Ascaris, hookworms)

1 (d) (ii) State two precautions that could be taken to reduce worm infestation in cattle.

• Regularly deworming cattle with appropriate anthelmintics.
• Practicing rotational grazing to break the life cycle of worms and reduce pasture contamination.

1 (d) (iii) State four ways in which these worms can harm their host.

• They compete for nutrients with the host, leading to malnutrition.
• They can cause damage to host tissues and organs, such as the intestines or liver.
• Some worms cause blood loss, leading to anemia.
• They can reduce growth rates and overall productivity (e.g., milk yield) in cattle.

2 (a) (i) State four ways in which excessive alcohol consumption is harmful to humans.

• Causes liver damage, such as fatty liver, alcoholic hepatitis, and cirrhosis.
• Leads to brain damage and cognitive impairment.
• Increases the risk of developing certain cancers, including those of the mouth, throat, esophagus, and liver.
• Can result in addiction and dependence, leading to social and psychological problems.

2 (a) (ii) List two effects of cigarette smoke on humans.

• Causes lung cancer and other respiratory diseases like emphysema and chronic bronchitis.
• Increases the risk of heart disease, stroke, and other cardiovascular problems.

2 (b) (i) Give the functional groups present in

• (α) Alcohol: Hydroxyl group (-OH)
• (β) Ethylene: Carbon-carbon double bond (C=C)
• (γ) Carboxylic acid: Carboxyl group (-COOH)
• (δ) Esters: Ester group (-COO-)

2 (b) (ii) Write down four differences between neutralization and esterification.

• Reactants: Neutralization involves an acid and a base, while esterification involves a carboxylic acid and an alcohol.
• Products: Neutralization produces a salt and water, while esterification produces an ester and water.
• Reaction type: Neutralization is typically an ionic reaction, while esterification is a covalent reaction.
• Catalyst: Neutralization usually does not require a catalyst, while esterification typically requires an acid catalyst (e.g., concentrated H$_2$SO$_4$).

2 (c) Define the following terms as applied to a simple machine, stating the effect of friction on each of them

• (i) Mechanical advantage: The ratio of the load (resistance force) to the effort (applied force). Friction reduces the mechanical advantage of a machine because more effort is needed to overcome friction.
• (ii) Velocity ratio: The ratio of the distance moved by the effort to the distance moved by the load. Friction does not affect the velocity ratio, as it is a theoretical value determined by the machine's design.
• (iii) Efficiency: The ratio of the useful work output to the total work input, often expressed as a percentage. Friction reduces the efficiency of a machine because some of the input energy is converted into heat due to friction, thus reducing the useful work output.

2 (d) (i) Name two tools used in the preparation of a nursery bed.

• Spade
• Rake

2 (d) (ii) State four factors you would consider in selecting a site for a nursery.

• Soil type and fertility: Needs well-drained, fertile soil.
• Water availability: Easy access to a reliable water source for irrigation.
• Sunlight exposure: Adequate sunlight for seedling growth.
• Protection: Shelter from strong winds, excessive rain, and pests.

2 (d) (iii) Mention two reasons for nursing seeds at the nursery.

• It allows for better control over environmental conditions (e.g., watering, pest control) during the critical early stages of plant growth.
• It helps to protect young seedlings from harsh weather conditions, pests, and diseases, leading to higher survival rates.

3 (a) (i) State four beneficial effects of microorganisms to humans.

• Food production: Used in making bread, cheese, yogurt, and fermented foods.
• Digestion: Gut bacteria aid in the digestion of food and synthesis of vitamins.
• Decomposition: Break down organic waste and dead organisms, recycling nutrients in the environment.
• Medicine production: Used to produce antibiotics and vaccines.

3 (a) (ii) State two reasons why organisms communicate with one another.

• To attract mates for reproduction.
• To warn others of danger or predators.

3 (b) (i) (α) What is a hydrocarbon?
A hydrocarbon is an organic compound that consists entirely of hydrogen and carbon atoms.

3 (b) (i) (β) Name three sources of hydrocarbons?

• Crude oil
• Natural gas
• Coal

3 (b) (ii) Determine how much water should be added to 30cm$^3$ of 0.2 mol/dm$^3$ NaCl solution to obtain 0.02 mol/dm$^3$.