chemistry chapter 13
• CH2-CH=CH-CH2 •The butadiene free radicals polymerize by reacting with each other. Thus, a polybutadiene will have the monomer unit;[-CH2-CH=CH-CH2-]How many double bonds does each repeating monomer unit in polybutadiene have?
1
How many electrons are removed from the double bond?
2
How many products are produced by a condensation reaction?
2
What is the percent gold in the following alloys. 14-karat yellow gold ____% 14-karat white gold ____ % 24-karat gold ____ %
58 58 100
The abbreviations for the two types of polyethylene are; high-density _____ low-density _____
HDPE, LDPE
Which polymer contains chlorine?
PVC
The polymers which contain halogen elements are P____ and t_______.
PVC Teflon
he polymers which contain halogen elements are P____ and t_______.
PVC teflon
When you find gold in nature it always occurs as the native ___.
element
The nitrogen in fertilizers comes from a___.
ammonia
Polymerization starts by ______ carbon/carbon double bonds.
breaking
Copper's main use is as an e___ c___.
electrical conductor
A polyester is a polymer that contains many _____ groups.
ester
Nylon readly reacts with other chemicals.
false
The United States can supply all of its mineral needs. (true, false)
false
Watch the video about the importance of chemistry's impact on history. Based on this video, the most important chemical contribution to history was the production of f_____ from hydrogen and nitrogen.
fertilizer
Chalcopyrite minerals attach to air bubbles because they are h___.
hydrophobic
Recycling steel is (important, unimportant).
important
The largest produced metal in the world is ___.
iron
Natural rubber is made from the monomer
isoprene
Condensation reactions produce l______ molecules and s______ molecules.
large small
During zone refining of silicon, impurities concentrate in the (solid, liquid) phase.
liquid
Smelting of an ore always produces a molten m__.
metal
Leaching bauxite ore with a hot concentrated NaOH solution dissolves the Al2O3. The hot aluminate solution is cooled and diluted with slightly acidic water. This precipitates the aluminum in solution as a pure aluminum hydroxide. Al(OH)4-(aq) + H3O+(aq) → Al(OH)3(s) + 2H2O(l) Calcining (heating) the hydroxide at 1000oC drives off water, producing purified aluminum oxide. 2Al(OH)3(s) → Al2O3(s) + 3H2O(l) Are these reactions oxidation-reduction reactions? (yes, no)
no
A p-n junction allows current to flow in __ direction.
one
What type of polymer is nylon?
polyamide
Thus, the extraction of a metal from its ore using heat is ___.
pyrometallurgy
After oxidation, silicon and phosphorus impurities in molten pig iron are removed in the s___.
slag
Limestone in the blast furnace is used to make ___.
slag
Low-density polyethylene is
soft
Which polymer contains benzene rings?
styrofoam
re there other addition polymers besides polyethylene
yes
Roasted copper ore is smelted at temperatures above its melting point. During smelting air is blown through the molten ore which converts the copper sulfide to the oxide according to the reaction; 2Cu2S(l) + 3O2(g) → 2Cu2O(l) + 2SO2(g)As the Cu2O is produced, it immediately reacts with Cu2S to produce metallic copper by the reaction; 2Cu2O(l) + Cu2S(l) → 6Cu(l) + SO2(g)The copper produced by this reaction is called 'blister' copper because it contains bubbles of SO2 gas. The overall reaction during the smelting process is; __Cu2S(l) + __O2(g) → __Cu(l) + __SO2(g)
1 1 2 1
The monomers used to make condensation polymers must each have how many functional groups?
2
Count the number of carbon atoms between amide linkages in; silk ___ wool ___ nylon ___
2, 2, 6
How many ester bonds are produced by the reaction between two diacids and two dialcohols?
3
Reduction of one mole of aluminum requires __ moles of electrons.
3
A p-type semiconductor (p for positive) results when small amounts of atoms with three valence electrons, such as boron are added to the silicon. An electron 'hole' is created at the impurity site as seen in figure (c) below. The electron hole gives the lattice an apparent positive charge. The electron holes serve as a means by which electrons, under an electric field, can 'hop' through the lattice. When a neighboring electron fills a hole, it creates a new hole in its original position.Doping with impurity atoms from which group will make p-type semiconductors?
3A
p-type semiconductors are made by doping with group ___ elements.n-type semiconductors are made by doping with group ___ elements.
3A, 5A
Pure gold is too soft to be used in jewelry, so it is alloyed with copper, silver, and other metals which increase its hardness. The amount of gold in these alloys is given in terms of karats. Pure gold is 24-karat and the amount of gold in its alloys is compared to this value. Thus, 14-karat gold contains 14 out of 24 parts (by mass) gold. The percent gold in 14-karat jewelry is (amt Au / total) x 100 = ___% Au (14 / 24 ) x 100 = ___% Au (nearest whole number)
58
Pure gold is too soft for jewelry use and must be alloyed with other metals. The metals used to form gold alloys vary, depending on the color and other properties that are desired. The following table lists the composition of a few typical 14-karat gold alloys. The amount of gold in all these alloys is ___ %. The second most abundant metal in yellow gold is ___.
58.33 copper
Doping ultrapure silicon results in two types of semiconductors depending on the identity of the impurity used. A n-type semiconductor (n for negative) is produced when atoms with five valence electrons, such as arsenic, are added to the silicon. When arsenic substitutes for silicon the extra fifth valence electron gives the lattice an apparent negative charge as seen in figure (b) below.Doping with impurity atoms from which group will make n-type semiconductors?(use arabic number)
5A
Many kinds of nylon have been produced, but nylon ___ (number) is the most common and used in largest amounts.
6
The formation of Nylon-66 (or any other polyamide) follows the general reaction for condensation polymer formation. The reaction of one acid group of the diacid with one amine group of the diamine produces a long polymer molecule of nylon. A portion of a Nylon-66 molecule with several amide linkages is show below. (You should notice that there are six carbon atoms between each nitrogen atom.) How many carbon atoms are between each nitrogen atom?
6
How many carbon atoms are in the dioic acid?How many carbon atoms are in the diamine?
6, 6
The most common and largest used nylon is Nylon-___ (number).
66
As noted earlier, gold is found in nature as the pure metal. However, many gold ores are very low-grade containing less than 0.1 oz per ton of ore. Gold in very low-grade deposits is recovered by leaching with cyanide solutions. Crushed ore is pelletized by the addition of small amounts of cement and stacked in large heaps and sprayed with NaCN solution. In the leaching process, gold is oxidized in the presence of air and CN- forming a stable water soluble complex. The leaching reaction is; 4Au(s) + 8CN-(aq) +O2(g) + 2H2O(l) → 4Au(CN)2-(aq) + 4OH-(aq)As the cyanide solution drains through the ore, the gold is dissolved. The 'pregnant' leach solution is collected at the base of the heap and stored in ponds until it can be processed to recover the dissolved gold.What polyatomic anion (formula) is able to dissolve gold?
CN-
What is the active reducing agent in the blast furnace? (formula)
CO
What is the formula of the substance added to the blast furnace to make slag?
CaCO3
Which elements are added to steel to make springs? (element symbols)
Cr V
Which of these pyrometallurgical processes are done at temperatures below the melting point of the ore?
calcining, roasting
The source of heat in blast furnace is the combustion of c___. (element name)
carbon
The 'backbone' structure of nylon is not just a chain of carbon atoms; it is a chain containing both c___ and n___ atoms.
carbon nitrogen
Which of the following is/are sulfide ores?
chalcoprite galena
Which of the following is an important source of copper?
chalcopyrite
Neoprene rubber contains which halogen element?
chlorine
The monomer used to make PVC has a ________ (element name) substituted for a hydrogen in ethene.
chlorine
An ester is produced by a c_________ reaction.
condensation
The most expensive part of metal recovery from its ore is c___ .
crushing
The most expensive part of metal recovery is the ___ step.
crushing grinding
Aluminum oxide melts at temperatures over 2000oC. This temperature is too high to permit it to be used for molten salt electrolytic reduction to aluminum metal. However, Al2O3 dissolves in molten cryolite (Na3AlF6) which has a melting point of 1012oC. A diagram of the electrolytic cell is shown below. The electrode reactions are;Anode: C(s) + 2O2-(l) → CO2(g) + 4e-Cathode: 3e- + Al3+(l) → Al(l)The discovery that molten cryolite could dissolve Al2O3 was the key to Hall's and Heroult's processes. Today, the demand for cryolite cannot be met from natural sources, and it must be produced synthetically.The key to electrolytic production of aluminum was the solubility of Al2O3 in molten ___.
cryolite
What material when molten is used to dissolve aluminum oxide when making aluminum metal?
cryolite
A polyamide (nylon) molecule is formed by the reaction of diacids with di___ .
diamides
All polymer molecules have (the same, different) numbers of repeating units.
different
The process used to make ultrapure silicon a semiconductor is called ___.
doping
The purpose of burning coke in a blast furnace is (a) to produce reducing gases (b) to produce heat (c) to produce carbon monoxide gas (d) to produce gaseous reactants (e) all of the above
e
Aluminum is obtained from a Al2O3-Na3AlF6 mixture by
electrolysis
Let's consider the operation of a p-n junction. Suppose the p-n junction is connected to a battery with the p-type junction in contact with battery's positive terminal and the n-type junction in contact with the negative terminal as shown in figure (a) below. Positive holes are continuously generated in the p-region as electrons are removed, and negative charges are continuously formed as electrons enter the n-region. This causes the holes in the p-region and electrons in the n-region to move towards each other. At the interface the electrons combine with the positive holes which allows current to flow through the semiconductor. Current is conducted by a semiconduct when both e___ and h___ move towards each other.
electrons holes
To increase the concentration of copper in an ore, it must be crushed to a very fine size and then beneficiated to remove the gangue minerals. The process used to concentrate the copper sulfide minerals is called f____.
flotation
The monomer used to make Teflon has _________ (element name) substituted for all the hydrogens in ethene.
fluorine
Carbon/carbon double bonds can be broken by molecules that produce f_____ r______.
free radicals
The process of obtaining copper from its ore is complicated by two major factors. First, the low-grade of the ore, and second, the presence of large amounts of iron. Because copper ores are very low-grade, the first step to increase the copper concentration is to remove the g___.
gangue
Unwanted minerals which occur in an ore deposit are called ___.
gangue
As copper is transferred from the impure electrode to the pure electrode, gold and silver impurities do not dissolve and fall to the bottom of the electrolytic cell forming a 'sludge.' The sludge is collected and processed to recover the valuable metals. The anode sludges from copper refining cells account for 25 percent of U.S. silver production and about 10 percent of the U.S. gold production.Copper refining produces large amounts of g___ and s___.
gold silver
High-density polyethylene is (soft, hard).
hard
The most important ores of iron contain the oxide minerals h__ and m__.
hematite, magnetite
Copper used in electrical wiring must be very pure - 99.95 percent. Even small amounts of impurities reduce its electrical conductivity. An electrolytic cell used for the purification of copper is shown below. Impure blister copper is cast into anodes and thin stainless sheets are used as cathodes. The electrolyte contains copper (II) sulfate. Electrolysis makes the impure copper dissolve and causes pure copper to 'plate out.' The oxidation reduction reactions are: Anode: Cu(impure) → Cu2+ + 2e- Cathode: Cu2+ + 2e- → Cu(pure)The net effect of electrolysis is to transfer the i___ copper in the anode to the p___ copper cathode.
impure pure
Precipitation of magnesium ion from seawater forms (soluble, insoluble) magnesium hydroxide
insoluble
Excluding monetary bullion, approximately half of the demand for gold is for jewelry and arts. One-third of gold's demand is for industrial uses including electronics (corrosion-free contacts), aerospace applications, and special alloys. Dental applications account for most of the remaining gold use. Only a small amount of gold is used for investments like medallions and coins.Most gold is used to make j___.
jewelry
Rapid expansion of high pressure-cold air will condense it to a l__.
liquid
To separate the three main gases in air, it must first be in which state (solid, liquid, gas).
liquid
A large polymer chain is called a(monomer, macromolecule).
macromolecule
A polymer chain is called a m___________.
macromolecule
The main metal obtained from sea water is ____.
mag
Steels which contain tungsten and molybdenum are very hard at high temperature and are used for m___ m___.
metal machining
An alloy is a
metallic material that is composed of two or more metals
The production and use of metals is called ____.
metallurgy
The monomer used to make polypropylene has a ______ group substituted for a hydrogen in ethene.
methyl
A naturally occurring solid chemical compound is a ___.
mineral
Naturally occurring substances in the earth are called ____.
minerals
The three main gases obtained from the atmosphere are n___, o___, and a___.
nitrogen oxygen argon
Are the compositions of minerals always fixed? (yes, no)
no
Can gold present in seawater be economically recoverd? (yes, no)
no
Do ores usually occur as silicate minerals? (yes, no)
no
Does polyethylene contain other elements besides carbon and hydrogen?
no
Suppose the battery is connected to the p-n junction as shown in figure (b). The holes in the p-region are attracted to the negative wire, and electrons in the n-region are attracted to the positive wire. Therefore, the junction quickly becomes depleted in charge carriers and no current can flow through the semiconductor.Will current flow in a semiconductor when the holes and electrons move away from each other? (yes, no)
no
The hot carbon dioxide gas rises and reacts with additional carbon falling through the furnace to form carbon monoxide. C(s) + CO2(g) → 2CO(g)Since this is an endothermic reaction, the temperature drops to 1300oC. The carbon monoxide produced in this reaction is the reducing agent for the iron oxide ore.Does the solid carbon in a blast furnace react with the solid iron oxide ore? (yes, no)
no
18 karat gold contains ___ % gold
no correct answer
Lighting is a common use of the n__ g__.
noble gases
Nitrogen is a colorless, odorless, and tasteless gas with a boiling point of -196oC. The N2 molecule is very nonreactive because of the strong triple bond between the nitrogen atoms (941 kJ/mol). Because of its low reactivity, large quantities of N2 are used in processing and packaging of foods and the fabrication of metals and electronics. Liquid N2 is used as a coolant to rapidly freeze foods. Flash freezing foods gives smaller ice crystals than conventional freezing. Large ice crystals rupture food cells and tissue, which affects its appearance and taste. Nitrogen is chemically (reactive, nonreactive).
non
A deposit that contains economically exploitable quantities of ametal is called a(n)
ore
The refining of an ore always involves what type of chemical reactions?
oxidation reaction
Metal purification usually involves what type of reactions?
oxidation reduction
After concentration, the ore is refined to extract the copper metal from the chalcopyrite mineral. Basicly two processes occur during refining. Roasting: 2CuFeS2(s) + 4O2(g) → Cu2S(s) + 2FeO(s) + 3SO2(g) Smelting: 3Cu2S(l) + 3O2(g) → 6Cu(l) + 3SO2(g)The roasting process drives off moisture and converts the iron sulfides to iron oxide, but leaves the copper as the sulfide. Thus, during roasting, the iron sulfides are more easily converted to ___ than are the copper sulfides.
oxides
Carbon and sulfur impurities in molten pig iron are removed by reaction with ___.
oxygen
1st most abundant element in the earth and its crust is ___. 2nd most abundant element in the crust is ___. 3rd most abundant element in the curst is ___.
oxygen silicon aluminum
what are in the earth
oxygen, silicon, aluminum, iron, magnesium, aluminum
Free radical species are formed by heating oganic p_____.
peroxides
The monomer used to make styrofoam has a _______ group substituted for a hydrogen in ethene.
phenyl
The polystyrene contains what group substituted for H?
phenyl
The iron produced in the blast furnace still contains impurities and is called 'pig' iron. The approximate composition of pig iron is 90% iron, 5% carbon, 2% manganese, 1% silicon, and <1% phosphorus and sulfur. The impurities make pig iron very brittle. Cast iron is made by melting pig iron with scrap iron. The resulting cast iron is still quite brittle and is used in items subjected to sudden mechanical or thermal shock. Typical uses include drain pipes, steam radiators, stove parts.Cast iron is made from p__ i__.
pig iron
A di-acid and a di-alcohol react to produce what condensation polymer?
polyester
Di-acids and a di-alcohols react to produce _______ polymers.
polyester
Many permanent press clothes contain p_____ fibers.
polyester
Polyethylene is an (addition
polymer
Which polymer contains methyl branches?
polypropylene,
The chloride derivative of polyethylene is the polymer __________.
polyvinylchloride
A large number of metallurgical processes utilize high temperature to extract a metal from its ore (mineral). The use of heat to alter or reduce the metal compound in the ore is called pyrometallurgy. Pyro means fire or heat. Thus, the extraction of a metal from its ore using heat is ___
pyrometallurgy
Teflon is best known as an anti-stick coating on pots, pans, and other cooking utensils. Because Teflon is non-reactive, food even when heated to high temperature, does not react with Teflon. Thus, food does not stick to Teflon. Gortex, a Teflon containing material that is water resistant, is used to make shoes and clothes water repellant.Teflon is a polymer that is non-_________.
reactant
Iron is produced in a blast furnace by the r__ of iron ores.
reduction
Elemental silicon is a gray metallic looking solid that melts at a high temperature (1410oC). Industrially, silicon is prepared by heating silica (SiO2) with carbon at 2000oC in an electric furnace. 2000oC SiO2(l) + 2C(s) → Si(l) + 2CO(g)Pure silicon has a structure identical to that of diamond. Each silicon atom is attached by strong covalent bonds to four other silicon atoms. Elemental silicon is produced by (oxidation, reduction) of silica with c___.
reduction carbon
Gold and platinum group metals are found in nature in the metallicform because they are
relatively inert
Rubber is a polymer made from the monomer __________.
butadiene
Most of the world's rubber production is used to make____.
tires
Many metals come from heating rocks containing metal compounds with charcoal. (true, false)
true
The condensation reaction between diacids and dialcohols will produce MANY ester bonds. (true, false)
true
The natural fibers of silk and wool are very similar in structure to nylon-6.(true, false)
true
The process of adding sulfur to rubber to improve its properties is called _________.
vulcanization
The reaction to produce an amide also produces a w___.
water
Does an ethene have a lone electron after reacting with a peroxide free radical?
yes
Magnesium metal is a liquid at temperatures these temperatures. The molten magnesium is drained from the reactor and the chlorine gas is recycled to make more hydrochloric acid. Does the production of magnesium from seawater use and oxidation-reduction reaction? (yes, no)
yes
The silicon used in electronic devices must be ultrapure. The purity of silicon (98 percent) obtained by carbothermic reduction in an electric furnace is not sufficient for these applications. Additional purification involves converting the Si to liquid SiCl4 followed by distillation and reduction of the SiCl4 with hydrogen. 900oC Si(s) + Cl2(g) → SiCl4(g)900oC SiCl4(g) + H2(g) → Si(s) + 2HCl(g)Are both these reactions oxidation-reduction reactions? (yes, no)
yes
Will the polymer unit formed from butadiene have a double bond? (yes, no)
yes
Gold is recovered from cyanide solutions using z__ reduction.
zinc
Magnesium is present in seawater as the aqueous ion ___.
Mg2+
Mg(OH)2(s) + 2HCl(aq) → MgCl2(aq) + 2H2O(l)You should notice that the above reaction is a neutralization reaction (base with and acid). What is the formula for the salt produced by this neutralization reaction?
MgCl2
After concentration, the ore is refined to extract the copper metal from the chalcopyrite mineral. Basicly two processes occur during refining. Roasting: 2CuFeS2(s) + 4O2(g) → Cu2S(s) + 2FeO(s) + 3SO2(g) Smelting: 3Cu2S(l) + 3O2(g) → 6Cu(l) + 3SO2(g)What element is used to remove sulfur from copper ore during smelting? (formula)
O2
What are the major impurities in aluminum ores?
SiO2 Fe2O3
Hydrometallurgy is
the use of water to locate underground ore deposits
The large molecule produced in the equation between a diacid and a dialcohol, as shown below, still has an acid group on one end and an alcohol group on the other end.The large molecule contains both an ac___ and al_______ functional group.
acid, alcohol
Polyethylene is an (addition, condensation) polymer.
addition
What type of polymer reaction produces a large molecule from the same small molecules without the formation of other products?
addition
Which noble gas is most abundant in the atmosphere?
argon
Most nitrogen comes from the a___.
atmosphere
The three main sources for raw materials are the a____, h____, and l____.
atmosphere hydrosphere lithosphere
Aluminum oxide can be dissolved in a hot (acidic, basic) solution.
basic
Which of the following is an important source of aluminum?
bauxite
A process used to concentration an ore is called ____.
beneficiation
Condensation polymers often involve ______ monomers.
bi-functional
Potassium containing fertilizers come from ____.
seawater
Elemental silicon is used as a s____
semiconductor
The word silicon in today's technological world turns most people's thoughts to the micro electronics industry. The link between silicon and the electronics industry involves the concept of semiconductors. A semiconductor is a substance that weakly conducts electricity. Thus, semiconductors have electrical properties between metals and nonmetals. The functioning of all micro-electronics is based on semiconductor properties.Micro-electronics require the use of s____.
semiconductor
During the flotation process, a froth is produced by blowing air through a water mixture of finely ground ore while it is vigorously stirred. The hydrophobic sulfide minerals attach to the air bubbles and are carried to the top of the tank and suspended in the froth. Since the silicate rock and clay particles are hydrophilic, they are easily wet and sink to the bottom of the tank. Because the copper sulfide particles float and the silicate and clay particles sink a (mixing, separation) of the copper minerals and gangue occurs.
separation
Most rocks contain s___.
silicates
A common element used in many semiconductors is ___. (element name)
silicon
where n is a large number (40,000 or more in most cases).The repeating unit is the same as the monomer except the double bond is changed to a _______ bond.
single
During the smelting process, limestone and silica are added as fluxing agents to remove the iron oxide. As the roasted ore melts, a molten slag layer forms by the reaction of CaO (from the limestone), SiO (silica), and FeO. CaO(s) + SiO2(s) → CaSiO3(l) FeO(s) + SiO2(s) → FeSiO3(l)Thus the iron oxide and silicate impurities are removed in the s__.
slag
The slag is a very important part of the smelting process. A slag serves two basic functions. First, it removes the impurities present in the ore. The slag consists of the gangue minerals (mostly silicates) and a fluxing agent such as limestone. Second, the slag floats on the surface of the molten metal, protecting it from unwanted oxidation by the furnace atmosphere. Therefore, a metallurgist can control the metal purity by controlling the chemistry of the ___.
slag
What is the substance called that removes impurities from molten metal during refining.
slag
Oxygen produced in the United States is mainly used for the production of s____.
steel
The metals considered most strategic are nickel, chromium, cobalt, manganese, and platinum group metals (Ru, Os, Rh, Ir, Pd, and Pt). Therefore, some very imported metals are considered to be s___ metals.
strategic
Therefore, some very imported metals are considered to be s___ metals.
stratigic
Many egg-cartons and hot-drink cups are made out of the polymer _________.
styrofoam
Most copper ores are s___ m___.
sulfide minerals
Ebonite is a hard rubber that contains up to one-half its weight in s______.
sulfur
The properties of natural rubber are improved by adding the element _______.
sulfur
Which polymer contains fluorine?
teflon