Chemistry - 9202 OxfordAQA

Nanoparticles C

Bayani Gaba-gaba

Photographs of lifeguards from forty years ago show a white stripe painted across the nose. The cream that made the stripe was zinc oxide, and it worked: nothing gets past it. Walk into a pharmacy today and you can buy a sunblock that contains the same zinc oxide, at a similar strength, that goes on completely clear. No new element was discovered to achieve that, and the formula on the tube is still ZnO. The one thing the manufacturer changed was how large the pieces of solid are.

That is the whole surprise of this topic. Chop a familiar substance small enough and it stops behaving the way the textbook says it should. It may melt at a lower temperature, catalyse a reaction it used to ignore, change colour, or lose its colour altogether. This lesson explains where the cut-off lies, gives you the piece of arithmetic that predicts the change before you ever see the substance, and then asks the question that governments are still arguing over: if a material behaves like a different substance at this size, is it safe to assume the old safety data still applies to it?

Manufura

  1. Nanoscience refers to structures that are 1-100 nm in size, of the order of a few hundred atoms. Nanoparticles show properties different from those for the same materials in bulk and have a high surface area to volume ratio, which may lead to the development of new computers, new catalysts, new coatings, highly selective sensors, stronger and lighter construction materials, and new cosmetics such as suntan creams and deodorants. Students should know what is meant by nanoscience and nanoparticles and should consider some of the applications of these materials, but do not need to know specific examples or properties. Questions may be set on information that is provided about these materials and relating their use to their structure.

Taswirar tunani

An zana wannan batu don ka ga yadda ra'ayoyi ke hadewa.

Bude taswirar tunani a cikin manhaja

Takardar Darasi

Zinc oxide is a white solid. That is not an opinion about one sample; it is a property, printed in data books, as settled as its melting point. Yet the clear sunblock on the pharmacy shelf contains zinc oxide at around a fifth of its mass, and you can read a newspaper through a smear of it. Nothing has been added to cancel the whiteness. The manufacturer has simply ground the solid until the individual pieces are a few tens of nanometres across, and at that size the whiteness stops happening.

Cikakken Bayanin Darasi Yana Kan Manhajar Green Bridge

Sami manhajar Green Bridge CBT a wayarka ko kwamfutarka domin cikakken laburaren IGCSE: takardun jarrabawar baya, tsarin kimantawa, taswirar tunani, katunan karatu da darussan sauti.

Cikakkiyar bayanan darasi tare da zane-zane
Mataimakiyar koyo da AI
Jarrabawar gwaji mai lokaci da ake kimantawa da zarar ka gama
Akwai a Android, Windows, macOS, da Linux Manhajar iOS tana zuwa nan ba da jimawa ba

Nazarin Darasi

Barka da kammala darasi akan Nanoparticles C. Yanzu da kuka bincika mahimman raayoyi da raayoyi, lokaci yayi da zaku gwada ilimin ku. Wannan sashe yana ba da ayyuka iri-iri Tambayoyin da aka tsara don ƙarfafa fahimtar ku da kuma taimaka muku auna fahimtar ku game da kayan.

Za ka gamu da haɗe-haɗen nau'ikan tambayoyi, ciki har da tambayoyin zaɓi da yawa, tambayoyin gajeren amsa, da tambayoyin rubutu. Kowace tambaya an ƙirƙira ta da kyau don auna fannoni daban-daban na iliminka da ƙwarewar tunani mai zurfi.

Yi wannan ɓangaren na kimantawa a matsayin wata dama don ƙarfafa fahimtarka kan batun kuma don gano duk wani yanki da kake buƙatar ƙarin karatu. Kada ka yanke ƙauna da duk wani ƙalubale da ka fuskanta; maimakon haka, ka kallesu a matsayin damar haɓaka da ingantawa.

  1. Nanoscience refers to structures with sizes in the range: A. 0.1 nm to 1 nm B. 1 nm to 100 nm C. 100 nm to 1000 nm D. 1000 nm to 10 000 nm Answer: B
  2. What is 1 nanometre expressed in metres? A. 1 x 10^-3 m B. 1 x 10^-6 m C. 1 x 10^-9 m D. 1 x 10^-12 m Answer: C
  3. A cube of a solid has edges of length 4 nm. What is its surface area to volume ratio? A. 0.67 nm^-1 B. 1.5 nm^-1 C. 96 nm^-1 D. 384 nm^-1 Answer: B
  4. A given mass of a metal is a better catalyst when it is supplied as nanoparticles rather than as a single lump. This is because the nanoparticles have: A. a larger volume B. a lower density C. a higher surface area to volume ratio D. a different chemical formula Answer: C
  5. Which statement about a nanoparticle of zinc oxide is correct? A. It has a different chemical formula from bulk zinc oxide. B. It has the same formula as bulk zinc oxide but may show different properties. C. It has the same properties as bulk zinc oxide in every respect. D. It is a single molecule of zinc oxide. Answer: B

Yi aikin wadannan tambayoyi a cikin manhaja

Yi aikin wadannan tambayoyi a cikin manhaja

Yi Aikin Tambayoyin Gwaji

Kana son yin aikin tambayoyin gwaji kan Nanoparticles C? Sauke manhajar Green Bridge CBT don samun tambayoyin gwaji da cikakkun jarrabawa akan wannan batu.

Sauke Manhajar Daga Google Playstore

Duk abin da kake buƙata don yin fice a JAMB, WAEC & NECO.

Green Bridge CBT Mobile App
Keɓantaccen Mataimaki na Tattaunawa na Koyo na AI
Tambayoyin jarrabawa na IGCSE, JAMB, WAEC da NECO fiye da 200,000.
Fiye da Lura-Luran Darussa 1200
Tallafin Wajen Layi - Koyo Kowane Lokaci, Ko'ina
Jadawalin Gadar Kore.
Takaitaccen Bayanin Adabi & Tambayoyin Da Za Su Iya Tashi
Bibiye Ayyukanka da Ci Gaban Ka
Cikakken Bayani don Koyon Fahimta.