OCR GCSE Chemistry A (J248) — Elements, compounds and mixtures
You might wear sunscreen to protect your skin, but the invisible particles inside it could potentially be entering your bloodstream as you rub it in. Nanoparticulate materials carry unique risks compared to their bulk counterparts. This danger comes down to two main physical properties: their extremely small size and their massive surface area to volume ratio.
Because nanoparticles are between 1 nm and 100 nm in diameter, they can easily bypass the body's natural physical defenses. They are small enough to be breathed directly into the lungs or absorbed through the skin and digestive tract.
Nanoparticles also pose a significant threat to ecosystems. Products like antibacterial socks containing silver or sunscreens containing titanium dioxide eventually wash down the drain and into natural water systems. This can cause aquatic toxicity, harming fish and accumulating in the food chain.
A major issue with nanotechnology is that the long-term risks are simply unknown. Because the technology is relatively new, these materials have not been in widespread use for long enough for scientists to detect long-term health or environmental side effects.
Students often state that the risks of nanoparticles are 'not fully understood'. Examiners do not accept this vague phrasing; you must explicitly state that there are 'unknown long-term health risks' because the technology is too new.
For 'Explain' questions about nanoparticle risks, always link the biological danger (e.g., cell damage) directly back to their physical properties (small enough to pass through cell membranes OR highly reactive due to a large surface area to volume ratio).
When discussing environmental impacts, specifically mention that nanoparticles 'take a long time to break down' and can transport other toxins that stick to their large surface area.
Nanoparticulate materials
Substances composed of tiny particles with diameters between 1 nm and 100 nm.
Surface area to volume ratio
A measure of how much surface area is available relative to the total volume of an object.
Toxicity
The degree to which a substance can damage a living organism or tissue.
Cell membranes
The semi-permeable boundary surrounding a cell that controls which substances can enter and exit.
Bio-persistence
The tendency of a substance to remain in a biological system or the environment for a long time without being broken down.
Put your knowledge into practice — try past paper questions for Chemistry A
Nanoparticulate materials
Substances composed of tiny particles with diameters between 1 nm and 100 nm.
Surface area to volume ratio
A measure of how much surface area is available relative to the total volume of an object.
Toxicity
The degree to which a substance can damage a living organism or tissue.
Cell membranes
The semi-permeable boundary surrounding a cell that controls which substances can enter and exit.
Bio-persistence
The tendency of a substance to remain in a biological system or the environment for a long time without being broken down.
