Crystalline Structure PDF

**CRYSTALLINE STRUCTURE** 1.The stacking pattern of SCC, BCC, and FCC is \_\_\_\_\_\_\_\_\_\_\_\_\_ respectively. **AAAA, ABAB, ABCABC respectively** 2.Identify the type of crystalline structure: graphite **covalent crystal** 3.This arrangement of atom results in the greatest stability of solid...

**CRYSTALLINE STRUCTURE** 1.The stacking pattern of SCC, BCC, and FCC is \_\_\_\_\_\_\_\_\_\_\_\_\_ respectively. **AAAA, ABAB, ABCABC respectively** 2.Identify the type of crystalline structure: graphite **covalent crystal** 3.This arrangement of atom results in the greatest stability of solid. **fcc** 4.An element crystallizes in a face-centered cubic lattice and has a density of 1.456 g/cm3. The edge of its unit cell is 4.52 x 10-8 cm. How many atoms are there in each unit cell? **4 atoms** 5.The atoms are closely packed, wherein orbitals overlap allowing loosely bonded electrons to move from one atom to another resulting into a "sea of electrons". **metallic crystal** 6.Identify the type of crystalline structure: Aluminum (Al) **metallic crystal** 7.Which substance is ionic and exhibits electrostatic force of attraction? **salt** 8.Which of the following is a characteristic of amorphous solid? **unsymmetrical structure** 9.Identify the type of crystalline structure: diamond **covalent crystal** 10.An element crystallizes in a face-centered cubic lattice and has a density of 1.456 g/cm3. The edge of its unit cell is 4.52 x 10-8 cm. What is the volume of a unit cell? **9.23 𝑥 10−23𝑐𝑚9.23 x 10−23cm** 11.Polonium is the only metal that forms a simple cubic crystal. Its coordination number is \_\_\_\_\_\_. **6** 12.Identify the type of crystalline structure: ice **molecular crystal** 13.Which of the following substances is an example of covalent network crystal? **diamond** 14.Which substance exhibits both H-bonding and dipole-dipole attraction? **𝑖𝑐𝑒 (𝐻2𝑂)ice (H2O)** 15\. All alkali metals possess a body centered crystal structure. This means that they contain\_\_\_\_\_\_\_\_. **2 atoms per unit cell** 16.Identify the type of crystalline structure: silver (Ag) **metallic crystal** 17.Which substance is held by dispersion force? **𝑑𝑟𝑦 𝑖𝑐𝑒 (𝐶𝑂2)dry ice (CO2)** 18.Identify the type of crystalline structure: silicon dioxide **covalent crystal** 19.Most of the metals possess a face-centered crystal structure. Which of the following statements is not true about the structure? **It has a density lower than scc and bcc.** 20.Identify the type of crystalline structure: Magnesium chloride (MgCl2) **ionic crystal** 21.Assuming that there is a face-centered cubic model made using a polysterene ball. What is the radius of the element if the edge length is 13.5 cm. **4.77 cm** 22.This arrangement of atom results in the greatest stability of solid. **fcc** 23.Identify the type of crystalline structure: KCl **ionic crystal** 24.An element crystallizes in a face-centered cubic lattice and has a density of 1.456 g/cm3. The edge of its unit cell is 4.52 x 10-8 cm. What is the mass of a unit cell? **1.34 𝑥 10−22𝑔1.34 x 10−22g** 25.Which statement describes ionic crystals? Ionic crystals are **compounds which are held by very strong electrostatic forces.** 26.Which substance has mobile electron cloud as a binding force? **Cu wire** 27.Identify the type of crystalline structure: dry ice **molecular crystal** 28.Identify the type of crystalline structure: Gold (Au) **metallic crystal** 29.In simple cubic, \_\_\_\_\_\_\_\_. **Second- and third-layer spheres are directly over a first-layer sphere.** 30.Plastics, glass, polymer, and gels are examples of \_\_\_\_\_\_\_\_. **amorphous solids** **METALS ** 1\. Which condition/s will cause the iron to rust? A test tubes with different liquids Description automatically generated with medium confidence **A and B** 2\. What gas is released when magnesium is reacted with dilute sulfuric acid? **hydrogen gas** 3\. Active metals release hydrogen from acids. **True** 4\. Transition metals in their ores are colored **True** 5\. The copper metal obtained by roasting copper sulfide usually contains impurities such as zinc, iron, silver, and gold. To purify it, procedure shown below was done. As shown, impure copper acts as the anode and pure copper acts as the cathode in a sulfuric acid solution containing Cu+2ions. This process is called \_\_\_\_\_\_\_\_\_\_. **electrolysis** 6\. The mineral from which iron is extracted is: **hematite** 7\. Which of the following decreases the rate of corrosion of iron? Presence of \_\_\_\_\_\_\_. **more active metals** 8\. Corrosion is a chemical reaction that involves **the surface of the object changing from an element to a compound** 9\. Metals have high ionization and electron affinity. **False** 10\. Metals have high melting point because \_\_\_\_\_\_. **of the strength of the electrostatic attraction between the metal ions and electrons** 11\. Metals react slowly with oxygen in the air, forming metal oxide. **True** 12\. Alkali metal reacts with water to form metal hydroxide and hydrogen gas. **True** 13\. Which of the situations below is unlikely? **Copper pipes are less appropriate to use in laboratories than iron and lead pipes.** 14\. Which of the following is not a spontaneous reaction (or should be no reaction)? **Mg + NaCl → MgCl2 + Na** 15\. Arrange the following metal in the decreasing chemical activity series \(i) Potassium (ii) Magnesium (iii) Gold (iv) Iron **(i), (ii), (iv) and (iii)** 16\. Which of the following will not show evolution of gas? **Cu + HCl** 17\. Metals react with halides to form salts. **True** 18\. What does the image tells us? **magnesium is more active than lead.** 19\. Metals usually react by gaining electrons to other atoms. **False** 20\. Which has the greatest and least evolution of gas? **calcium and copper respectively** 21\. Which of these reactions is possible? **Zn + CuO → ZnO + Cu** 22\. Which metal will react with Zinc nitrate? **Aluminum** 23\. Alkali earth metals exhibit the following except \_\_\_\_\_\_\_. **These metals react with base to form hydrogen gas.** 24\. Which of the following is NOT a property of a metal?**\ It is a good heat insulator.** 25\. Metals are dense because \_\_\_\_\_\_. **of close-packed arrangement of atoms** 26\. Which are NON-spontaneous reactions? B, E, F 27\. This reaction depicts the following EXCEPT \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_. **Copper is less active than silver, thus is reduced while silver is oxidized.** 28\. Metals tend to form cations and almost have positive oxidation numbers **True** 29\. Metals are lustrous because \_\_\_\_\_\_. **when heat touches the metal, the loosely bonded electron vibrates easily and radiate the heat with the same frequency and wavelength** 30\. Which is incorrect about copper metal? **it is good oxidizing agent than iron.** 31\. The effect of connecting other metals to an iron nail was investigated. From the observations you can deduce? **iron is less reactive than magnesium** 32\. Which of the following does not protect the iron from corrosion? **attaching metal with copper** 33\. Active metals are good oxidizing agents. **False** 34\. Metal oxides form acids with water. **False** 35\. Copper is used in electrical cable mainly because \_\_\_\_\_\_\_\_. **it is ductile** **POLYMERS ** 1\. Which one of the following is not a natural polymer? **nylon** 2\. Which one of the following polymer structures is known to be strong? **linear** 3\. Which is NOT TRUE about thermoplastic polymers? **they cannot be shaped into the desired form** 4\. Vulcanized rubber is \_\_\_\_\_\_\_\_\_\_. **thermosetting polymer** 5\. Plastics are made from what starting material? **petroleum or oil** 6\. Polyethylene (PE) is \_\_\_\_\_\_\_\_\_\_. **thermoplastic polymer** 7.One of the critical properties of polymers is elasticity. The ability of many polymeric materials to be stressed and deformed but return to their original shape is a characteristic that is often valuable to engineers. Suggest a reason why polymer molecules are mostly elastic. **made of amorphous solid** 8\. Which of the following is not a man-made polymer? **cotton** 9\. Polypropylene (PP) is \_\_\_\_\_\_\_\_\_\_. **thermoplastic polymer** 10\. Which of the following will be formed from these monomers? **C** 11\. There are two main types of polymerization, the first being addition. Which of these is a requirement of monomers in order to undergo addition polymerization? **The presence of a carbon to carbon double bond.** 12\. The syndiotactic form of polypropane is \_\_\_\_\_\_. **D** 13\. During condensation polymerization, many monomers join together. What is lost when two monomers join together via a condensation reaction? **water** 14\. Which of the following is made with ethylene and is considered dense? **B** 15\. What type of bond is common in all polymers? **covalent bond** 16\. Phenyethene is the monomers of \_\_\_\_\_\_\_\_. **𝑝𝑜𝑙𝑦𝑠𝑡𝑦𝑟𝑒𝑛𝑒(−\[𝐶𝐻2−𝐶𝐻(𝐶6𝐻5)\]𝑛−)** 17\. Diacid plus diol yields \_\_\_\_\_\_ and water. **ester** 18\. LDPE is \_\_\_\_\_\_\_. **addition polymer** 19\. What is polymer? **A large molecule made by monomers.** 20\. The isotactic form of polypropane is \_\_\_\_\_\_. **A** 21**.** Which of the following does not formed via condensation reaction? **D** 22\. High density polyethylene in general is \_\_\_\_\_\_\_\_\_. **massive than LDPE** 23\. Nylon is \_\_\_\_\_\_\_. **condensation polymer** 24\. Polymers formed via addition polymerization are often used as plastics. The atoms/groups which make up the monomers determine the properties of the plastic. An example of this is "vinyl". Which monomers join together to form vinyl? **Chloroethene** 25\. Which describes block copolymer? **has regions in the material where a single monomer unit is repeated, interspersed with other regions where a different monomer is the repeating unit.** 26\. Cotton is \_\_\_\_\_\_\_. **condensation polymer** 27\. Why is there no isotactic or syndiotactic form of polyethylene? **monomer is symmetrical.** 28\. What makes PVA or polyvinyl alcohol with high glass transition temperature? Existence of \_\_\_\_\_\_\_. **hydrogen bonding** 29\. Teflon is a polymer that can be used as \_\_\_\_\_\_. **non-stick surfaces** 30\. Which is NOT TRUE about thermosetting polymers? **they offer increased strength but lose their shape upon further heating.** **\ EXERCISE: NANOTECHNOLOGY ** 1.Which of the following statements best describe the origin of fluorescence emission of quantum dots? **The fluorescence emission of quantum dots is attributed to its surface plasmon resonance.** 2.All of the following techniques are top-down method for preparing nanomaterials EXCEPT **Chemical vapor deposition** 3.Quantum dots are fluorescent materials; hence, they could be potentially used for bioimaging. What could be the plausible hindrance for quantum dots to be used in this field? Heavy metals (e.g. lead and cadmium) are typical precursors of quantum dots; therefore, they are considerably toxic. **All of the above.** The fluorescence emission of quantum dots is usually too dim for bioimaging. The size of quantum dots is too small to be used for bioimaging. 4.Which of the following statements best describes the electronic properties of graphene?. **The carbon atoms are sp2 hybridized and conjugated; thus, electrons can move from one carbon atom to another carbon atom.** 5.What is the bottom-up process for fabrication of thin films on a substrate that requires bombardment of gaseous reactants? **Chemical vapor deposition** 6.A substance is considered a nanomaterial if at least one of its dimensions is in the size range is within \_\_\_\_\_\_\_\_\_\_. **1 nm to 100 nm** 7.Which of the following commercial products contains a nanomaterial ingredient? **All of the above** Sunblock Pregnancy test kit Antimicrobial socks 8.The process for fabricating and printing of desired nanostructured shapes and structures by selectively removing a portion of a material is called \_\_\_\_\_\_\_\_\_\_\_. **Nanolithography** 9.Which of the following statement is majorly considered as an advantage of using metal nanoparticles as catalyst over bulk metallic materials? **Metal nanoparticles have higher surface-to-volume surface area compared to bulk materials.** 10.The color of the largest size quantum dots is \_\_\_\_\_\_\_\_\_\_. **red** **Which of the following patterns is not a copolymer?** **AAAAAAAAAAAAAAAAAA** **Atoms that attacks ozone is** **Cl** **Which one of the following polymer structures is exhibited by low density polyethylene (LDPE)?** **Branched** **Which of the following will not evolve hydrogen gas, which is an indicator that it is good for piping than the other metals?** **Cu + HCl** **Warming of the atmosphere is due to the greenhouse effect. What is responsible for this phenomena?\* (1 Point)** **The CO2 level in the atmosphere is increased.** **Currently, the thinnest and strongest existing material in the world is** **Graphene** **An example of a metal that is extracted by electrolysis is:** **sodium** **Which will make the concentration of dissolved oxygen in water to increase?** **removing salt from water** **Potassium forms bcc structure. Which of the following describes potassium?** **It has a packing efficiency which is not too high; the atom oc- cupies only about 68% of the space.** **Palladium crystallizes in a face-centered cubic unit cell. Its density is 12.023 g/cubic cm. What is the mass of Palladium?** **1.77x10 -22 g** **Used as catalytic converters in car exhaust to control and minimize the pollutant emitted by vehicles. \* (1 Point)** **Metallic nanoparticles** **The refining of a pure metal in a blast furnace is called** **Smelting** **What type of solid is known for their ability to flattened into sheet, stretched into wire, and conduct electricity? \* (1 Point)** **Metallic** **Aluminum crystallizes in fcc arrangement, potassium forms bcc structure and polonium follows scc structure. Which of the following metals has the highest density? \*** **aluminum** **Which illustrates safety precaution in a working area?\* (1 Point)** **Assess risk from exposure and take all necessary precautions.** **High density polyethylene in general is** **massive than LDPE** **Tony is a resident of Manila. He usually experiences labored breathing, eye irritation, and prolonged coughing. What might be the possible cause of his recurring illness?** **air pollution** **All of the following techniques are top-down method for preparing nanomaterials EXCEPT** **Chemical vapor deposition** **One of the disruptions of natural processes aside from depletion of natural resources and disturbance of the natural condition of the earth that causes environmental degradation is pollution. Which is not a cause of pollution? \* (1 Point)** **extinction and migration** **Metals have high melting point because** **of the strength of the electrostatic attraction between the metal ions and electrons** **The process for fabricating and printing of desired nanostructured shapes and structures by selectively removing a portion of a material is called?** **Nanolithography** **Graphene is a?** **carbon nanomaterial** **Which of the following statements is NOT true about quantum dots?** **A nanoparticle whose size range between 2 and 10 nm** **Have higher surface area than metallic nanoparticle** **Used in drug delivery** **Emits intense fluorescence** **The longest bio-geochemical cycle is** **nitrogen** **phosphorus** **carbon and oxygen** **water** **Which is NOT an application of nanotechnology? \*** **self-cleaning windows** **stainproof clothing** **improved adhesion and anti-fungal qualities** **none of these** **Which of the following describes a bucky ball? \*** **a quantum dot** **plastic explosives nanoparticle** **a concrete nanoparticle with a comprehensive strength of 20 nanonewton** **a carbon molecule (C60)** **The atoms are closely packed, wherein orbitals overlap allowing loosely bonded electrons to move from one atom to another resulting into a \"sea of electrons\". \* (1 Point)** **metallic crystal** **covalent crystal** **ionic crystal** **molecular crystal** **What is the atomic packing factor of BCC structure?** **0.68** **0.54** **0.96** **0.74** **Metals are malleable and ductile because \* (1 Point)** **the electrons are mobile.** **of the strength of the electrostatic attraction between the metal ions and electrons** **of close-packed arrangement of atoms** **when heat touches the metal, the loosely bonded electron vi- brate easily and radiate the heat with the same frequency and wavelength.** **Which of the following methods will NOT prevent corrosion? \* (1 Point)** **Coating metals with less oxidizable metal** **By attaching a more reactive metal** **By using chemical to form a surface coating** **Alloying the metal with other metals** **Which of the following is NOT a property of a metal?** **It is malleable.** **It is dense.** **It is shiny.** **It is a good heat insulator.** **Which is NOT true among the following statements?** **Photosynthesis uses carbon dioxide and produces oxygen.** **Cellular respiration uses oxygen and produces carbon dioxide.** **During respiration, organisms attach a carbon to the hydro- gen and release carbon dioxide.** **Plants take the carbon off the carbon dioxide freeing the oxy- gen so it can be used for respiration.** **Atomic packing factor refers to \*** **the geometric arrangement of the atoms in the cell** **projected area fraction of atoms on a plane** **distance between two adjacent atoms** **volume ratio of an atom inside the unit cell** **Which of the following is responsible for the rise in temperature in the stratosphere? \* (1 Point)** **height of the stratosphere** **position of the stratosphere** **nearness to the sunlight** **presence of the ozone** **Aluminum crystallizes in fcc arrangement, potassium forms bcc structure and polonium follows scc structure. Which of the following metals has packing efficiency which is not too high; the atom occupies only about 68% of the space..?** **polonium** **potassium** **aluminum** **Which metal will react with Zn(NO3)2?\*** **Cu** **Al** **Hg** **Ag** **Which of the following polymers readily undergo degradation upon application of heat and pressure before they melt and reshaped? \* (1 Point)** **elastomer** **fiber** **Thermosets** **Thermoplastics** **A polymer synthesis method wherein a bulk material is destructively reduced until its size reaches into nano-sized parameters. \* (1 Point)** **Pyrolysis** **Top-down method** **Sol-gel** **Bottom-up methos** **Clearing of forest will make the concentration of CO2 to (1 Point) and oxygen gas to \*** **decrease, increase** **increase, decrease** **both increase** **both decrease** **Coordination number for face-centered crystal structure. \* (1 Point)** **4** **12** **16** **8** **An element crystallizes in a face-centered cubic lattice and has a density of 1.456 g/cubic cm. The edge of its unit cell is 4.52 x 10-8 cm. How many atoms are there in each unit cell? \* (1 Point)** **1** **2** **6** **4** **Which describes block copolymer? \*** **(1 Point)** **monomers are arranged in a regular, alternating series.** **monomers are randomly combined.** **involve side chains of one polymer attached to a backbone of a different polymer.** **has regions in the material where a single monomer unit is repeated, interspersed with other regions where a different monomer is the repeating unit.** **Paper has a long history. Its name is derived from papyrus, a sedge that flourishes along the banks of the Nile River. In ancient times, the Egyptians extracted the fibrous interior of this plant to fashion a kind of writing material. Is PAPER a POLYMER? \* (1 Point)** **Yes** **No** **Which is an effect of organic or oxygen demanding waste? \* (1 Point)** **promotes algal bloom which blankets the body of water** **stay in the environment for a long time** **wastes produce unpleasant odor and color, decomposition causes multiplication of microorganisms** **lethal at relatively low concentration and maybe mutagenic** **Aluminum crystallizes in fcc arrangement, potassium forms bcc structure and polonium follows scc structure. Which of the following metals has coordination number of 12 thus allow each atom in the lattice to interact with more nearest neighbor atoms? \* (1 Point)** **potassium** **polonium** **aluminum** **Teflon is a polymer that can be used as \*** **(1 Point)** **latex paints** **toys and cabinet packaging** **rugs and blankets** **non-stick surfaces** **Nanomaterials are substances with at least one dimension between** **(1 Point)** **1 and 10 pm** **1 and 100 pm** **1 and 10 nm** **1 and 100 nm** **Metals are malleable and ductile because \* (1 Point)** **when heat touches the metal, the loosely bonded electron vi- brate easily and radiate the heat with the same frequency and wavelength** **of the strength of the electrostatic attraction between the metal ions and electrons** **of close-packed arrangement of atoms** **the electrons are mobile** **The lower layer of the atmosphere where all atmospheric phenomena such as typhoons, etc occur is the \* (1 Point)** **exosphere** **trophosphere** **mesosphere** **stratosphere** **An element crystallizes in a face-centered cubic lattice and has a density of 1.456 g/cubic cm. The edge of its unit cell is 4.52 x 10-8 cm. What is the volume of a unit cell? \* (1 Point)** **9.23 x10-23 ст** **-3 5.65 x 103 cm** **2.12 x 10-4 ст** **9.04 x 10-9 cm** **Which of the following statements is NOT CORRECT? (1 Point)** **Water has a high heat capacity and heat of vaporization** **Water exhibits hydrogen bonding** **Water has high surface tension** **Water is non-polar** **Fishkills regularly take place on hot summer days. Fishkills occur in summer due to** **eutrophication** **increase in biological oxygen demand** **decrease in dissolved oxygen** **increase in dissolved oxygen** **Aluminum crystallizes in fcc arrangement, potassium forms bcc structure and polonium follows scc structure. Which of the following metals has the highest density? \* (1 Point)** **polonium** **potassium** **aluminum** **Which of the following monomers is suitable for condensation polymerization? \* (1 Point)** **Propene** **Ethane** **Diacid and Diamine** **Vinyl chloride** **The design, characterization, production and application of structures, devices and systems by controlling shape and size at 1x10-9 scale is called** **nanotechnology** **microscience** **microtechnology** **nanoscience** **Which of the following is a greenhouse gas? \*** **Sulfur dioxide** **Ozone** **carbon dioxide** **Nitrogen** **Aluminum crystallizes in fcc arrangement, potassium forms bcc structure and polonium follows scc structure. Which of the following metals has edge length equal to the diameter of one atom, allowing the corner atoms to touch one another? \*** **aluminum** **polonium** **potassium** **Aluminum crystallizes in fcc arrangement, potassium forms bcc structure and polonium follows scc structure. Which of the following metals has one atom located at the corner of the cube, and additional atoms placed at the center of each of the six faces of the cube.?\* (1 Point)** **aluminum** **potassium** **polonium** **Repeatable entity of a crystal structure is known as \*** **Miller Indices** **Unit cell** **Lattice** **Crystal** **Which statement is INCORRECT? \* (1 Point)** **Connecting a less reactive metal from lower in the series pro- tects from corrosion. A higher (more reactive) metal accepts electrons from iron and speeds up the rusting process.** **Air and moisture cause normal rusting.** **Salt solution acts as an electrolyte allowing iron to lose elec- trons more easily and so speeds up the rusting process.** **Using paint or grease creates a barrier which physically stops oxygen/water from reaching the metal.** **A polymer that forms by simple linking of monomers units without loss or gain of materials. \*** **Thermosets** **Condesation polymer** **Addition polymer** **Thermoplastics** **Which is NOT TRUE? \* (1 Point)** **Acid rain kills all form of vegetation.** **Minerals can be leached out of the soil by the acids, and they are carried off into the groundwater, thus increasing the food nutrients of plants.** **Acids corrode metals and decompose stone buildings and marble statues.** **Any form of precipitation that has a pH below 5.6 is con- sidered to be acid rain.** **What will happen to the amount of dissolved oxyg if the water sample has high turbidity similar to the figure below?\* (1 Point)** **Dissolved oxygen will increase, then decrease.** **Dissolved oxygen will increase.** **Dissolved oxygen will decrease.** **No change, dissolved oxygen is not related to turbidity** **Which describes nitrogen fixation reaction? It is the process that converts.** **inorganic nitrogen back into the ecosystem as ammonia.** **nitrate to nitrogen gas, thus removing bioavailable nitrogen and returning it to the atmosphere** **nitrogen gas into biologically available nitrogen** **ammonia to nitrite and then to nitrate** **Which of the following statements is generally incorrect? \* (1 Point)** **At very small sizes physical properties (magnetic, electric and optical) of materials can change dramatically.** **Nanomaterials exist in nature.** **Nanomaterials have tremendous application be in the field of science, construction, semiconductors, medicine etc.** **Nanomaterials can be developed only.** **Which is not a cause of eutrophication? \* (1 Point)** **fertlilizers** **detergents** **carbon dioxide** **clearing of forest through the mining of phosphates rocks** **Metals are lustrous because (1 Point) \*** **when heat touches the metal, the loosely bonded electron vi- brate easily and radiate the heat with the same frequency and wavelength.** **of the strength of the electrostatic attraction between the metal ions and electrons** **of close-packed arrangement of atoms** **the electrons are mobile.** **A group of carbon and hydrogen containing compounds which are gases at ambient temperature is \* (1 Point)** **carbon monoxides** **asbestos** **hydrocarbons** **petrochemical oxidants** **Aluminum crystallizes in fcc arrangement, potassium forms bcc structure and polonium follows scc structure. Which of the following metals has one atom per unit cell?** **potassium** **polonium** **aluminum** **Which of the following statements best describes the electronic properties of graphene? \* (1 Point)** **The carbon atoms are sp2 hybridized and conjugated; thus, electrons can move from one carbon atom to another carbon atom.** **Carbon atoms in graphene are surrounded by a sea of elec- trons that can freely move from one carbon atom to another carbon atom.** **None of the above.** **The element carbon is metallic in nature; hence, it is a good conductor of electricity.** **Wool, cotton and silk are examples of \_ polymers. \* (1 Point)** **inorganic** **natural** **organic** **synthetic** **Why is there no isotactic or syndiotactic form of polyethylene?\* (1 Point)** **monomer is unsymmetrical** **monomer is symmetrical** **monomer can form only alternating or block polymer** **monomer can form only graft or random polymer** **Copper is used in electrical cable mainly because** **it is ductile** **it is strong** **it is malleable** **it is very dense metal** **n-type semiconductors** **are produced when Indium is added as an impurity to Germanium** **are produced when boron is added as an impurity to silicon** **are produced when phosphorous is added as an impurity to silicon** **uses trivalent impurity atoms** **Aluminum crystallizes in fcc arrangement, potassium forms bcc structure and polonium follows scc structure. Which of the following metals has atoms at the corners of the cube and an atom** **placed at the center of the cube.r\* (1 Point)** **aluminum** **polonium** **potassium** **When Pt and Co are electrically connected, which will not be corroded? \* (1 Point)** **Co** **Both will corrode at the same rate** **None** **Pt** **When objects (gates) are galvanized, what metal is used to protect the iron. \* (1 Point)** **Al** **Cu** **Ni** **Zn** **Which does not demonstrate safe handling of chemicals? (1 Point)** **Chemicals must be stored with closed lids when they are not being used.** **Chemicals must be stored and labelled in accordance with the instructions on the safety sheet.** **Chemicals which are combustible must be stored in a fire- proof cupboards.** **Chemicals must be stored together with flammable material and gas cylinders.** **Which of the following is NOT true for the Group 1A elements? \* (1 Point)** **They are excellent conductors of heat and electricity.** **Most of them are soft, silvery corrosive metals.** **Their atomic radii increases with increasing molecular weight.** **They are named the alkaline earth metals.** **Which of these is a requirement of monomers in order to undergo addition polymerization? \* (1 Point)** **The presence of an oxygen atom.** **The presence of a carbon to carbon double bond.** **The presence of a carbon to carbon triple bond.** **The presence of a lone pair.** **Which animal do scientists currently consider to be at the highest risk of extinction? \* (1 Point)** **monkeys** **polar bears** **rabbits** **dogs** **The stacking pattern of simple cubic crystal structure is** **ABCABC** **AABAAB** **AAAAAA** **ABABAB** **Which of the following take place during cathodic protection (for example: attaching Mg in Fe nail)? \*** **The sacrificial metals accepts electrons from the protected metal** **The sacrificial metal oxidizes more readily than the protected metal** **The sacrificial metal reacts spontaneously with the protected metal** **The sacrificial metal act as the cathode.** **Which of the following statements is INCORRECT? \*** **Nanomaterials have tremendous application be in the field of science, construction, semiconductors, medicine etc.** **Nanomaterials can be developed only.** **At very small sizes physical properties (magnetic, electric and optical) of materials can change dramatically.** **Nanomaterials exist in nature.** **Metals are dense because** **of close-packed arrangement of atoms** **of the strength of the electrostatic attraction between the metal ions and electrons** **when heat touches the metal, the loosely bonded electron vi- brate easily and radiate the heat with the same frequency and wavelength.** **the electrons are mobile.** **Which reactions below is considered incorrect? \*** **MgO + H2O Mg(OH)2** **Na + H2O NaOH** **Ca + 02 CaO** **Na + Cl2 NaCl** **CFCs are family of compounds containing the elements carbon, fluorine and chlorine. Which of the following statements is NOT true about CFCs?** **CFCs were to be found in aerosol sprays and refrigerants** **Ozone is attacked by chlorine atom that breaks free from the CFC molecule** **CFCs can remain in the atmosphere from up to 100 years** **Each CFC molecule destroys a single ozone molecule** **An element crystallizes in a face-centered cubic lattice and has a density of 1.456 g/cubic. The edge of its unit cell is 4.52 x 10-8 cm. What is the mass of a unit cell ? \* (1 Point)** **1.34 x10-22 g** **5.18 x 10-21 g** **6.15 x 10-22 g** **1.32 x 10-7 g** **Which of the situations below is unlikely?** **A solution of ZnCl2 stored in an aluminum container was found to be impure.** **A magnesium bar is attached to a buried iron pipe to protect the pipe from corrosion.** **When a strip of zinc is placed for some minutes in a solution of CuSO4 the blue color fades away.** **Metals such as iron must be cleaned by acids.** **Palladium crystallizes in a face-centered cubic unit cell. Its density is 12.023 g/cubic cm. What is the edge length (a) of Palladium? (1 Point)** **3.08 \* 10 \^ - 8 \* cm** **2.45 \* 10 \^ - 8 \* cm** **3.88 \* 10 \^ - 8 \* cm** **4.5 \* 10 \^ - 8 \* cm** **Palladium crystallizes in a face-centered cubic unit cell. Its density is 12.023 g/cubic cm. Calculate the atomic radius of palladium in cm. \* (1 Point)** **5.77 \* 10 \^ - 8 \* cm** **1.38 \* 10 \^ - 8 \* cm** **1.76 \* 10 \^ - 8 \* cm** **2.22x10-8 cm** **Which crystal structure does the picture show?** **face centered** **simple cubic** **body centered** **hexagonal close packing** **Which of the following is a CRYSTALLINE SOLID material? \* (1 Point)** **Glass** **Wood** **Plastic** **Metal** **Which of the following is not a man-made polymer?** **polyamide** **polyurethane** **polysaccharide** **polypropylene** **One of the critical properties of polymers is elasticity. The ability of many polymeric materials to be stressed and deformed but return to their original shape is a characteristic that is often valuable to engineers. Suggest a reason why polymer molecules are mostly elastic. \* (1 Point)** **made of metallic solid** **made of amorphous solid** **made of crystalline solid** **made of ionic solid** **It is anything emitted into the atmosphere that alters the natural characteristics of the environment. \* (1 Point)** **pollutant** **pollution** **ecosystem** **erosion** **Palladium crystallizes in a face-centered cubic unit cell. Its density is 12.023 g/cubic cm. What is the volume of Palladium? \* (1 Point)** **8.82x10-23 cm³** **1.47x10-23 cm³** **5.88x10-23 cm³** **2.94x10-23 cm³** **Which is following metals has the greatest tendency to be oxidized? \* (1 Point)** **Lithium** **Magnesium** **iron** **copper** **Which of the following statements is incorrect? \*** **Metals react with halides to form salts.** **Active metals release hydrogen from acids.** **Metals react with oxygen in the air to metal oxide.** **Metal oxides form acids with water.**