Question 1: Define a solid, a liquid, and a gas in terms of particle arrangement and movement.

Answer: Solids have particles tightly packed in a fixed structure with little movement; liquids have particles close but free to move past each other; gases have particles far apart and move freely.

Question 2: Explain why oxygen is transported in the blood primarily as a dissolved gas and as part of the compound haemoglobin.

Answer: Oxygen dissolves poorly in blood plasma due to limited solubility, but it binds to haemoglobin in red blood cells, allowing efficient transport despite its low solubility.

Question 1: Calculate the volume of oxygen (O₂) in litres that a patient inhales in 10 minutes if their breathing rate is 15 breaths per minute, and each breath contains 0.5 litres of oxygen. Use the formula: Volume inhaled = breaths per minute × volume per breath × time in minutes.

Answer: Volume = 15 × 0.5 × 10 = 75 litres

Question 2: A medical oxygen cylinder contains 20 cubic metres of oxygen gas at a pressure of 150 atmospheres. Assuming ideal gas behaviour, calculate the volume of oxygen at atmospheric pressure (1 atm) and room temperature (25°C). Use the combined gas law: (P₁ × V₁) / T₁ = (P₂ × V₂) / T₂. (T in Kelvin: T = 25 + 273).

Answer: V₂ = (P₁ × V₁ × T₂) / (P₂ × T₁) = (150 × 20 × 298) / (1 × 298) = 3000 cubic metres

Question 1: Describe a simple method to demonstrate the expansion of gases when heated, relevant to medical equipment sterilisation, including safety precautions.

Answer: A basic method is heating air in a sealed tube and observing its expansion; safety precautions include using heat-resistant equipment, wearing safety goggles, and ensuring proper ventilation to avoid pressure build-up.

Question 2: Identify two variables that must be controlled during the storage of medical gases such as oxygen or nitrous oxide.

Answer: Pressure and temperature must be controlled to ensure safety and maintain gas quality.

Question 1: A patient is administered 5 litres of nitrous oxide gas at room temperature. If the pressure drops from 2 atmospheres to 1 atmospheres during administration, what is the new volume of the gas assuming temperature remains constant? Use Boyle's Law: P₁V₁ = P₂V₂.

Answer: V₂ = (P₁ × V₁) / P₂ = (2 × 5) / 1 = 10 litres

Question 1: Explain how the properties of gases make them suitable for use in medical ventilation and anaesthesia. Include considerations of compressibility, flow, and safety.

Answer: Gases are highly compressible, allowing easy storage and delivery at controlled pressures. Their ability to flow freely makes them ideal for ventilation and anaesthesia. Safety measures include proper regulation of pressure and monitoring for leaks or overexposure.

Question 1: Describe the role of liquids and gases in medical imaging technologies, such as MRI and X-ray contrast agents. How does the state of matter influence their function?

Answer: Liquids like contrast agents are used to enhance imaging by flowing through blood vessels, relying on their fluidity. Gases, such as in MRI contrast, must be in a state that allows safe inhalation and precise delivery, with their ability to change states influencing their effectiveness.