Materials Science Overview: Metals and Nanoparticles

Quantum Dots

• Nanoparticles with a size range of 2-10 nm
• Higher surface area than metallic nanoparticles
• Used in drug delivery
• Emit intense fluorescence

Biogeochemical Cycle

• Longest biogeochemical cycle is not specified in the provided text.

Malleability and Ductility of Metals

• Metals are malleable and ductile due to the mobile electrons within their structure.
• The close-packed arrangement of atoms also contributes.
• The loosely bonded electrons vibrate easily when heated, radiating heat.

Corrosion Prevention Methods

• Coating metals with less oxidizable metals prevents corrosion.
• Attaching a more reactive metal (sacrificial anode) prevents corrosion.
• Forming a surface coating using chemicals prevents corrosion.
• Alloying the metal with other metals prevents corrosion.

Properties of Metals

• Malleable - capable of being hammered or shaped
• Dense - high mass per unit volume
• Shiny - possess luster
• Good conductors of heat and electricity (not an insulator)

Photosynthesis and Respiration

• Photosynthesis uses carbon dioxide and produces oxygen.
• Cellular respiration uses oxygen and produces carbon dioxide.
• Respiration involves attaching a carbon to hydrogen and releasing carbon dioxide.
• Plants release oxygen as a by-product of photosynthesis for respiration.

Atomic Packing Factor

• The geometric arrangement of atoms within a unit cell.
• Fraction of atoms projected onto a plane (projected area fraction of atoms).
• Distance between adjacent atoms
• Volume ratio of atoms inside the unit cell.

Stratosphere Temperature Rise

• Ozone presence causes a rise in stratosphere temperature.

Metal Crystal Structures and Packing Efficiency

• Aluminum crystallizes in face-centered cubic (fcc) arrangement.
• Potassium forms body-centered cubic(bcc) structure.
• Polonium follows simple cubic (scc) structure.
• Polonium has the lowest packing efficiency (68% atom occupancy).

Metal Reactions with Zn(NO3)2

• Aluminum (Al) will react with Zn(NO3)2
• The other options, Copper (Cu), Mercury(Hg) and Silver(Ag) will likely not react.

Polymer Degradation

• Thermosets readily degrade from heat and pressure application.
• Unlike Thermoplastics that can be softened or melt without degrading permanently.

Polymer Synthesis Methods

• Pyrolysis is a method of reducing a bulk material to nano-sized parameters through destructive methods.
• Top-down method of synthesis starts with a larger material, progressively reducing its size to nano-scale dimensions.

Forest Clearing and Atmospheric Gases

• Clearing forests decreases the concentration of O2.
• Increases concentration of O2.

Coordination Number

• Face-centered cubic structure (fcc) has a coordination number of 12.

Atoms per Unit Cell

• An element crystallizing in a face-centered cubic lattice with a given density and unit cell edge length has 4 atoms per unit cell.

Block Copolymers

• Regions of one monomer unit interspersed with regions of a different monomer.

Paper as a Polymer

• Paper is derived from a plant and hence a natural polymer.

Effects of Organic Waste

• Organic wastes promote algal blooms, create unpleasant odors and colors due to decomposition causing an increase in microorganisms.
• They stay in the environment for a long time.

Metal Coordination Number

• Aluminum has the highest coordination number in the options given.

Teflon Applications

• Teflon is commonly used as a non-stick surface

Nanomaterial Dimensions

• Nanomaterials have at least one dimension between 1 and 100 nanometers.

Atmospheric Layer for Phenomena

• Troposphere is the lowest atmospheric layer where atmospheric phenomena occur.

Unit Cell Volume

• The unit cell volume of the given element is 9.23 * 10⁻²³ cm³.

Water Properties

• Water has high heat capacity and high heat of vaporization.
• Water exhibits hydrogen bonding.
• Water has high surface tension.
• Water is a polar molecule.

Fishkills

• Fishkills in hot summer days are likely due to decreased dissolved oxygen.

Metal Density

• Polonium has the highest density.

Monomers for Condensation Polymerization

• Diacids and diamines are suitable for condensation polymerization.

Design and Application Scale

• Nanotechnology involves the design, characterization, production, and application of structures, devices, and systems at the nanoscale.

Greenhouse Gases

• Carbon dioxide (CO2) is a greenhouse gas.

Edge Length and Atoms Per Unit Cell

• Polonium has atoms at the corner of the cube with corner atoms touching.

Repeatable Crystal Structure

• A unit cell is the repeatable entity of a crystal structure.

Acid Rain Effects

• Acid rain can negatively impact vegetation (killing it).
• Minerals leach out of soil (reducing plant nutrient availability).
• Metals and stone buildings are corroded.
• Precipitation with a pH below 5.6 is considered acid rain.

Dissolved Oxygen and Turbidity

• High turbidity decreases dissolved oxygen.

Nitrogen Fixation

• Nitrogen fixation is the process of converting atmospheric nitrogen gas into usable nitrogen compounds.

Nanomaterials

• Nanomaterials exist in nature.
• Nanomaterials' properties can drastically change at small scales.
• Nanomaterials have numerous scientific and applications across diverse fields.

Eutrophication Causes

• Fertilizers are a cause of eutrophication.
• Detergents are a cause of eutrophication.
• Clearing of forests through phosphate mining is a cause of eutrophication.
• Carbon Dioxide is not a cause of eutrophication.

Metal Lustre

• Metals are lustrous because of the mobility of electrons within their structure.

Carbon and Hydrogen Gases

• Hydrocarbons are compounds containing carbon and hydrogen existing as gases.

Atoms Per Unit Cell

• Polonium has one atom per unit cell.

Graphene Electronic Properties

• Graphene electrons can move between carbon atoms because of sp2 hybridization and conjugation.

Polymer Types

• Wool, cotton, and silk are natural polymers.

Polyethylene Isomerism

• Polyethylene does not have isotactic or syndiotactic forms because its monomer is symmetrical.

Copper Use in Electrical Cables

• Copper is a ductile metal used in electrical cables due to its ductility (the ability to be drawn into wires).

n-Type Semiconductors

• n-type semiconductors form when a pentavalent impurity (like phosphorus) is added to a tetravalent semiconductor (like silicon).

Metal Crystal Structure

• Aluminum has atoms at the corners of the cubic structure and center atoms.

Galvanization

• Zinc (Zn) is used to protect iron in galvanization.

Chemical Handling Safety

• Chemicals must be properly stored with closed lids, labelled, and stored separately from flammable materials or gases.

Group 1A Elements

• Group 1A elements are the alkali metals (not alkaline earth metals).
• They are good conductors of heat and electricity.
• Their atomic radius tends to increase with increasing molecular weight.

Additional Polymerization Monomers

• Monomers with a carbon-to-carbon double bond are required.

Endangered Animal

• The exact animal at highest risk of extinction isn't presented.

Simple Cubic Stacking

• A simple cubic structure's stacking pattern is not mentioned.

Cathodic Protection

• The sacrificial metal (more reactive) oxidizes and prevents the protected metal from oxidizing.

Incorrect Statements about Nanomaterials

• Nanomaterials can be developed only (incorrect)

Metal Density

• Metals are dense due to close-packed arrangements of atoms.

Chemical Reactions

• MgO + H2O → Mg(OH)2 (Correct)
• Na + H2O → NaOH (Correct)
• Ca + O2 → CaO (Correct)
• Na + Cl2 → NaCl (Correct)

CFCs

• CFCs were used in aerosol sprays and refrigerants.
• Chlorine atoms break free from CFCs and attack ozone.
• CFCs can persist in the atmosphere for up to a century.
• Each CFC molecule can destroy many ozone molecules.

Mass of Unit Cell

• The mass of the unit cell is 6.15 x 10⁻²² g.

Unlikely Situations

• A solution of zinc chloride stored in an aluminum container can be impure. (A likely occurrence)
• A magnesium bar being used to protect an iron pipe from corrosion. (A likely occurrence)
• Zinc strip placed in CuSO4 causing a color change.. (Likely)
• Iron cleaning using acids. (Likely)

Palladium Edge Length

• The edge length (a) of the Palladium unit cell is 3.88 * 10⁻⁸ cm.

Palladium Atomic Radius

• The atomic radius is 1.76x10⁻⁸ cm.

Crystal Structure Image

• The image (not shown) is needed to identify the crystal structure.

Crystalline Solid

• Metal is a crystalline solid.

Man-Made Polymer

• Polysaccharide is a natural polymer not a man-made one.

Polymer Elasticity

• Polymer elasticity is due to the amorphous structure within the polymer.

Pollutant

• Anything that alters the natural environment is a pollutant.

Palladium Volume

• The volume of Palladium is 8.82 x 10-²³ cm³

Oxidizing Metals

• Lithium is the metal with the greatest tendency to be oxidized.

Metal Reactions

• Metals reacting with halides form salts.
• Active metals react with acids to release hydrogen.
• Metals react with oxygen to form metal oxides.
• Metal oxides react with water to form acids.(Correct)