Introduction to Nanotechnology-Questions and Answers Graded A+

Introduction to Nanotechnology-Questions and Answers Graded A+ what is nanoscience? - ANSWER-study of objects and phenomena that occur at the nanoscale (1-100 nm) Properties of matter change as size changes from macroscale to nanoscale. Four aspects that this is due to: - ANSWER--dominance of electromagnetic forces -quantum effects -increase in surface area to volume ratio -influence of random molecular motion Three differences between quantum mechanics and classical mechanics: - ANSWER--energy is discrete (quantized energy) -matter and light exhibit "wave particle duality" - wavicle -terms of"probability" and things become more "uncertain" Example of quantum effects in nano gold. Explain. - ANSWER--in bulk, e- energy levels are "band like" - color does not vary with amount of gold -nanocrystaliline gold - e- energies are much more discrete - color of solutions containing nanocrystalline gold is dependent on size of gold nanoparticles why do nanoscale materials exhibit different phase change behavior than bulk materials? - ANSWER-because ratio of surface to volume is much higher than the same object with the same volume in bulk Melting point example of surface area to volume ratio. Explain - ANSWER--T at which solid becomes liquid -when molecules have enough E to overcome the intermolecular forces holding them in a solid lattice -molecules on surface- less interactions to overcome requiring less E -nanoparticles with very high SA - MP dependent on size of nanoparticle Scanning electron microscopy (SEM) - ANSWER-uses beams of e-'s to produce image why won't optical microscopes work for viewing nanomaterials? - ANSWER-these microscopes rely on the visible spectrum to view objects -can't resolve objects smaller than 400 nm (shortest wavelength of visible spectrum) Scanning probe microscopy (SPM) - ANSWER-produces 3D images - can be used to manipulate individual atoms and molecules in nanomaterials