Straighterline Chemistry Final Exam0with 100% verified solutions 2024-2025, Exams of Chemistry

Download Straighterline Chemistry Final Exam0with 100% verified solutions 2024-2025 and more Exams Chemistry in PDF only on Docsity! Straighterline Chemistry Final Exam0with 100% verified solutions 2024-2025 What is the term used for findings that are summarized based on a pattern or trend? a. Law b. Hypothesis c. Theory d. Phenomena e. Prediction - Answer a. Law Which of the following is a tentative explanation for a set of observations? Select one: a. Law b. Hypothesis c. Theory d. Phenomena e. Prediction - Answer b. Hypothesis If a liquid contains 60% sugar and 40% water throughout its composition then what is it called? Select one: a. Solute b. Compound c. Homogeneous mixture d. Heterogeneous mixture e. Solvent - Answer c. Homogeneous mixture Which of the following does not have a uniform composition throughout? Select one: a. Element b. Compound c. Homogeneous mixture d. Heterogeneous mixture e. Solvent - Answer d. Heterogeneous mixture Which one of these represents a physical change? Select one: a. Water, when heated, forms steam. b. Bleach turns hair yellow. c. Sugar, when heated, becomes brown. d. Milk turns sour. e. Apples, when exposed to air, turn brown. - Answer a. Water, when heated, forms steam. How many micrograms are in 65.3 kg? Select one: a. 0.653 μg b.6.53 × 107 μg c. 6.53 × 104 μg d. 6.53 × 10-8 μg e. 6.53 × 1010 μg - Answer e. 6.53 × 1010 μg A smart phone has dimensions of 4.9 inches (height), 2.3 inches (width) and 8.0 millimeters (depth). What is the volume of the smart phone in cubic centimeters? (1 in = 2.54 cm) Select one: a. 58 cm3 b. 1.7 x 105 cm3 c. 90 cm3 d. 3.4 cm3 e. 34 cm3 - Answer a. 58 cm3 Given that 1 inch = 2.54 cm, 1.00 cm3 is equal to Select one: a. 16.4 in3 b. 6.45 in3 c. 0.394 in3 d. 0.155 in3 e. 0.0610 in3 - Answer e. 0.0610 in3 What terms defines a mass which is exactly equal to 1/12 the mass of one carbon-12 atom? Select one: a. Isotope number b. Mass number c. Mass-to-charge ratio d. Atomic number e. Atomic mass unit - Answer e. Atomic mass unit How many neutrons are there in an atom of lead whose mass number is 208? Select one: a. 82 b. 126 c. 208 d. 290 Select one: a. hypochlorite b. chlorate c. chlorite d. perchlorate e. perchlorite - Answer a. hypochlorite Which of the following is a molecular formula for a compound with an empirical formula of CH? Select one: a. C2H6 b. C3H9 c. C4H10 d. C6H6 e. None of the answers is correct. - Answer d. C6H6 Which is the correct electron configuration for gold? Select one: a. [Xe]4f145d96s2 b. [Xe]4f145d106s2 c. [Xe]4f135d106s2 d. [Xe]4f145d106s1 e. None of the electron configurations is correct. - Answer d. [Xe]4f145d106s1 A(n) is a point at which a standing wave has zero amplitude. Select one: a. crevice b. node c. pit d. burrow e. orbital - Answer b. node The Pauli exclusion principle states that no electrons within an atom can have the same quantum numbers. Select one: a. 4; 6 b. 2; 4 c. 3; 6 d. 6; 10 e. 3; 8 - Answer b. 2; 4 Emission spectra Select one: a. cannot be used to identify an unknown atom. b. can be used to identify unknown atoms. c. can be explained by the movement of protons colliding with electrons. d. none of the. - Answer b. can be used to identify unknown atoms. Which one of the following equations correctly represents the process relating to the ionization energy of X? Select one: a. X(s) → X+(g) + e- b.X2(g) → X+(g) + X-(g) c. X(g) + e- → X-(g) d. X-(g) → X(g) + e- e. X(g) → X+(g) + e- - Answer e. X(g) → X+(g) + e- Consider the element with the electron configuration [Kr]5s24d105p5. This element is Select one: a. a halogen. b. a transition metal. c. an alkali metal. d. an actinide element. e. a noble gas. - Answer a. a halogen. Consider the element with the electron configuration [Kr]5s24d7. This element is Select one: a. a halogen. b. a transition metal. c. a nonmetal. d. an actinide element. e. a noble gas. - Answer b. a transition metal. How does atomic radius change as you move across the periodic table? Select one: a. Atomic radius decreases moving from left to right across a period and increases from top to bottom. b. Atomic radius increases moving left to right across a period and decreases from top to bottom. c. Smaller nuclear charge lowers energy; more electrons in an orbital lowers energy. d. Atomic radius increases diagonally across the periodic table. e. None of the answers is correct. - Answer a. Atomic radius decreases moving from left to right across a period and increases from top to bottom. Which of these choices is the electron configuration of the iron(III) ion? Select one: a. [Ar]3d5 b. [Ar]4s13d5 c. [Ar]4s23d3 d. [Ar]3d6 e. [Ar]4s23d9 - Answer a. [Ar]3d5 An element with the general electron configuration for its outermost electrons of ns2np1 would be in which element group? Select one: a. 2A b. 3A c. 4A d. 5A e. 8A - Answer b. 3A The effective nuclear charge for an atom is less than the actual nuclear charge due to Select one: a. shielding. b. penetration. c. paramagnetism. d. electron-pair repulsion. e. relativity. - Answer a. shielding. Which pair of ions exhibits the greatest attractive force between them? Select one: a. Na+ and Cl- b. Ca2+ and Cl- c. Na+ and S2- d. Al3+ and Mg2+ e. Mg2+ and O2- - Answer e. Mg2+ and O2- Which of the following is a basic oxide? Select one: a. P4O10 b. MgO c. Al2O3 d. SO2 e. Cl2O7 - Answer b. MgO Which of these compounds is most likely to be covalent? Select one: a. Rb2S b. SrCl2 c. CS2 d. CaO e. MgI2 - Answer c. CS2 In the Lewis structure of the iodate ion, IO3-, that satisfies the octet rule, the formal charge on the central iodine atom is d. C2H2; sp e. H2O; sp3 - Answer a. BeCl2; sp2 According to the VSEPR model, the predicted molecular geometry of ammonia, NH3, is Select one: a. linear. b. trigonal planar. c. bent. d. tetrahedral. e. trigonal pyramidal. - Answer e. trigonal pyramidal. What is the mass of one copper atom? (NA = 6.022 × 1023 mol-1) Select one: a. 1.055 × 10-22 g b. 63.55 g c. 1 amu d. 1.66 × 10-24 g e. 9.476 × 1021 g - Answer a. 1.055 × 10-22 g What is the percent sulfur in iron(III) sulfate? Select one: a. 28% b. 32% c. 24% d. 48% e. 42% - Answer c. 24% Proteins found in humans are polymers that consist of different combinations of 20 amino acids. Proline, one of the 20 amino acids, has the molecular formula, C5H9NO2. If a human protein has 25 proline monomers, how many carbon atoms from proline are present in the protein? Select one: a. 4 C atoms b. 25 C atoms c. 40 C atoms d. 100 C atoms e. 125 C atoms - Answer e. 125 C atoms Aluminum oxide, Al2O3, is used as a filler for paints and varnishes as well as in the manufacture of electrical insulators. Calculate the number of moles in 47.51 g of Al2O3. Select one: a. 2.377 mol b. 2.146 mol c. 1.105 mol d. 0.4660 mol e. 0.4207 mol - Answer d. 0.4660 mol Once the following equation is balanced with the smallest set of whole number coefficients, what is the sum of the coefficients? (Don't forget to include coefficients of one.) SF4 + H2O → H2SO3 + HF Select one: a. 4 b. 6 c. 7 d. 9 e. None of these answers is correct. - Answer d. 9 What is the theoretical yield of chromium that can be produced by the reaction of 40.0 g of Cr2O3 with 8.00 g of aluminum according to the chemical equation below? 2Al + Cr2O3 → Al2O3 + 2Cr Select one: a. 7.7 g b. 15.4 g c. 27.4 g d. 30.8 g e. 49.9 g - Answer b. 15.4 g Which one of the following is a strong acid? Select one: a. CH3COOH b. H2SO3 c. NH3 d. H3PO4 e. HClO3 - Answer e. HClO3 Which is a Lewis acid? Select one: a. CH3NH2 b. BCl3 c. F- d. BF4- e. CH4 - Answer b. BCl3 Which is an amphoteric oxide? Select one: a. Na2O b. MgO c. Al2O3 d. SO2 e. Cl2O7 - Answer c. Al2O3 What is the value of the equilibrium constant for the autoionization of water at 25°C? Select one: a. 1.0 × 10-7 b. 1.0 × 10-14 c. 1.0 × 1014 d. 1.0 × 107 e. 14 - Answer b. 1.0 × 10-14 Which is the strongest acid? Select one: a. SO42- b. H2SO3 c. H2SO4 d. HSO4- e. HSO3- - Answer C. H2SO4 In the van der Waals equation, the constant b is a constant that is part of a correction factor for . Select one: a. the volume of the gas b. the temperature of the gas c. the pressure of the gas d. the ideal gas constant - Answer a. the volume of the gas A sample of nitrogen gas at 298 K and 745 torr has a volume of 37.42 L. What volume will it occupy if the pressure is increased to 894 torr at constant temperature? Select one: a. 22.3 L b. 31.2 L c. 44.9 L d. 112 L e. 380 L - Answer b. 31.2 L If the atmospheric pressure in Denver is 0.8800 atm, what is this pressure expressed in mmHg? (1 atm = 101,325 Pa = 760 torr, 1 torr = 1 mmHg)? Select one: a. 151.5 mmHg b. 1.16 × 10-3 mmHg c. 863.6 mmHg d. 8.92 × 104 mmHg e. 668.8 mmHg - Answer e. 668.8 mmHg e. Supersaturated - Answer a. Unsaturated An emulsion is a dispersion consisting of a Select one: a. solid in a liquid. b. liquid in a liquid. c. gas in a liquid. d. liquid in a solid. e. gas in a solid. - Answer b. liquid in a liquid. Which is true regarding the solvation of a solute in a solvent? Select one: a. Separation of solute molecules from one another is an endothermic process, and separation of solvent molecules from one another is an exothermic process. b. Separation of solute molecules from one another is an exothermic process, and separation of solvent molecules from one another is an endothermic process. c. Separation of solute molecules from one another, and separation of solvent molecules from one another, are both endothermic processes. d. Separation of solute molecules from one another, and separation of solvent molecules from one another, are both exothermic processes. e. Separation of solute molecules from one another, and separation of solvent molecules from one another, both result in a decrease in entropy. - Answer b. Separation of solute molecules from one another is an exothermic process, and separation of solvent molecules from one another is an endothermic process. What name is given to a minor component in a solution? Select one: a. Solvent b. Unsaturated c. Saturated d. Solute e. Supersaturated - Answer d. Solute Which compound has the lowest solubility in pure water? Select one: a. Ag2C2O4, Ksp = 1.0 × 10-11 b. PbCl2, Ksp = 1.7 × 10-5 c. FePO4, Ksp = 1.3 × 10-22 d. Ca3(PO4)2, Ksp = 1.2 × 10-26 e. MgF2, Ksp = 6.9 × 10-9 - Answer c. FePO4, Ksp = 1.3 × 10-22 What happens to the solution if sodium acetate is added to a solution of acetic acid? CH3COOH(aq) Picture H+(aq) + CH3COO-(aq) Select one: a. The equilibrium shifts to the right. b.There is an increase in percent ionization of acetic acid. c. Less of hydrogen ion is consumed. d. There is an increased concentration of acetate ions. e. Less of the acetate ion is consumed. - Answer d. There is an increased concentration of acetate ions. Which is more soluble in an acidic solution than in pure water? Select one: a. CuI b. PbCl2 c. Ca3(PO4)2 d. NaNO3 e. NaBr - Answer c. Ca3(PO4)2 What is the name of the principle of selective precipitation used to identify the types of ions present in a solution? Select one: a. Ionization b. Selective ion precipitation c. Selective ion typing d. Limited precipitation e. Qualitative analysis - Answer e. Qualitative analysis Methyl red is a common acid-base indicator. It has a Ka equal to 6.3 × 10-6. Its un- ionized form is red and its anionic form is yellow. What color would a methyl red solution have at pH = 7.8? Select one: a. green b. red c. blue d. yellow e. violet - Answer d. yellow When a strong acid is titrated with a weak base, the pH at the equivalence point Select one: a. is greater than 7.0. b. is equal to 7.0. c. is less than 7.0. d. is equal to the pKa of the conjugate acid. e. is equal to the pKb of the base. - Answer c. is less than 7.0. Which is necessary for a process to be spontaneous? Select one: a. ΔHsys < 0 b.ΔSsys > 0 c. ΔSsurr < 0 a. cobalt(III) chloride monohydrate b. aquatrichlorocobalt(II) c. aquatrichlorocobaltate(II) d. aquatrichlorocobaltite(I) e. monoaquotris(chloro)cobalt(IV) - Answer c. aquatrichlorocobaltate(II) In K4[Fe(CN)6], how many 3d electrons does the iron atom have? Select one: a. 3 b. 4 c. 5 d. 6 e. 7 - Answer d. 6 Write the formula for diamminedichloroethylenediaminecobalt(III) bromide. Select one: a. [CoCl2(en)(NH3)2]Br b. [CoCl2(en)(NH3) 2]Br2 c. [CoCl2(en)2(NH3)2]Br d. [CoCl2(en)2(NH3)2]Br2 e. (NH3)2Cl2(en)Co3Br - Answer a. [CoCl2(en)(NH3)2]Br In the complex ion [Co(en)2Br2]+, what is the oxidation number of Co? Select one: a. +1 b. +2 c. +3 d. -2 e. -1 - Answer c. +3 In which type of isomerism is there restricted rotation around a bond? Select one: a. Stereoisomers b. Geometrical isomers c. Constitutional isomers d. Conformational isomers e. Connectivity isomers - Answer b. Geometrical isomers What name is given to a compound containing a -CONH2 group? Select one: a. Aldehyde b. Amine c. Amide d. Carboxylic acid e. Ester - Answer c. Amide Bromination of benzene (C6H6), an aromatic compound, Select one: a. occurs by substitution rather than addition. b. occurs by addition rather than substitution. c. occurs more rapidly than bromination of a nonaromatic compound. d. results in the formation of 1,2,3,4,5,6-hexabromocyclohexane. e. occurs in the absence of a catalyst. - Answer a. occurs by substitution rather than addition. The density of a substance is an intensive property. Select one: True False - Answer True The rusting of a piece of iron under environmental conditions is a physical change. Select one: True False - Answer False 77 K is colder than 4 K. Select one: True False - Answer False Zero kelvin 0 K < 0°F < 0°C Select one: True False - Answer True The number 6.0448, rounded to 3 decimal places, becomes 6.045. Select one: True False - Answer True A scoop of vanilla ice cream is a pure substance. Select one: True False - Answer False The juice from an orange is a mixture. Select one: True False - Answer True The ripening of fruit, once picked, is an example of physical change. Select one: True False - Answer False A particular temperature in degrees Celsius is larger than the temperature in kelvins. Select one: True False - Answer False Matter is anything that has mass and occupies space. Select one: True False - Answer True Elements in which the outermost electron has the same principal quantum number, n, show similar chemical properties. Select one: True False - Answer False Atomic size decreases across a period due to an increase in the effective nuclear charge, Zeff. Select one: True False - Answer True The radii of ions are always smaller than the radii of the corresponding atoms of the same element. Select one: True False - Answer False The electron configuration of atomic argon is the same as the chloride ion (Cl-). Select one: True False - Answer True Weak acids have weak conjugate bases. Select one: True False - Answer False The rate of diffusion of a gas is inversely proportional to its molar mass. Select one: True False - Answer False Gases are compressible and have a density that is much higher than liquids and solids. Select one: True False - Answer False For a gas obeying Boyle's law, a plot of V versus 1/P will give a straight line passing through the origin. Select one: True False - Answer False For real gases, PV > nRT. Select one: True False - Answer False When a closed-ended manometer is used for pressure measurements, and the closed end is under vacuum, the level of manometer liquid in the closed arm can never be lower than that in the other arm. Select one: True False - Answer True Ethanol (C2H5-OH) will have a greater viscosity than ethylene glycol (HO- CH2CH2-OH) at the same temperature. Select one: True False - Answer False Ice is less dense than water due to the formation of hydrogen bonds. Select one: True False - Answer True A face-centered crystal lattice has one atom in the center of the unit cell. Select one: True False - Answer False The energy of a hydrogen bond is greater than that of a typical covalent bond. Select one: True False - Answer False The maximum number of phases of a single substance which can coexist in equilibrium is two. Select one: True False - Answer False The endpoint is used to estimate the equivalence point. Select one: True False - Answer True If the pH of a buffer solution is greater than the pKa value of the buffer acid, the buffer will have more capacity to neutralize added base than added acid. Select one: True False - Answer False For a conjugate acid-base pair, Kw = Ka/Kb Select one: True False - Answer False The amount of strong acid added to a buffer solution cannot exceed the original amount of conjugate base present in order for the buffer to still work. Select one: True False - Answer True The endpoint in a titration is defined as the point when the appropriate indicator changes color. Select one: True False - Answer True Increasing the concentrations of the components of a buffer solution will increase the buffer capacity. Select one: True False - Answer True A CH3COOH/CH3COO- buffer can be produced by adding a strong acid to a solution of CH3COO- ions. Select one: True False - Answer True Indicators are weak acids that are one color in acidic solution and another color in basic solution. Select one: True False - Answer True The pH of a solution that is 0.20 M CH3COOH and 0.20 M CH3COONa should be higher than the pH of a 0.20 M CH3COOH solution. Select one: True False - Answer True Increasing the concentrations of the components of a buffer solution will increase the buffer range. Ernest Rutherford disproved J.J. Thomson's plum-pudding model of the atom by showing that a. atoms are, in fact, not electrically neutral. b. the atom contains neutrons. c. positive matter is concentrated in the central core. d. electrons are actually greater in mass than protons. - Answer c. positive matter is concentrated in the central core. What is the reducing agent in the following equation? Mg(s) + 2 HCl(aq) --> MgCl2(aq) + H2(g) a. Mg b. HCl c. H2 d. MgCl2 - Answer A. Mg How is the mass number of an element different from its atomic number? Select one: a. The mass number represents the total number of protons in one atom of the element as opposed to the total number of neutrons. b. The mass number represents the total number of electrons in one atom of the element as opposed to the total number of protons. c. The mass number represents the total number of neutrons and protons in one atom of the element as opposed to the total number of protons. d. The mass number represents the total number of neutrons and electrons in one atom of the element as opposed to the total number of neutrons. - Answer c. The mass number represents the total number of neutrons and protons in one atom of the element as opposed to the total number of protons What is Avogadro's number? Select one: a. the number of atoms in 12g of Carbon-12 b. the number of moles in 12g of Carbon-12 c. the number of molecules in 12g of Carbon-12 d. the number of periods in 12g of Carbon-12 - Answer a. the number of atoms in 12g of Carbon-12 What is the ratio of reactants and products in the chemical equation? NaOH + H2SO4 ==> Na2SO4 + H2O a. 1:1:1:1 b. 2:1:1:1 c. 1:1:1:2 d. 2:1:1:2 - Answer d. 2:1:1:2 The initial volume of a system containing 1 mole of an ideal gas at 292° Kelvin and 3 atm is 8 L. If the gas is cooled at constant volume until the pressure falls to 1.2 atm, then the gas is heated and expanded at constant pressure (1.2 atm) until the volume is 20 L and the temperature is 292° Kelvin, what is the overall work that has been done by the system? Select one: a. -5.29 kJ b. -1.46 kJ c. 3.84 kJ d. 12.78 kJ - Answer b. -1.46 kJ Most nonmetallic elements are found in which block of the periodic table of elements? Select one: a. s b. p c. d d. f - Answer b. p Which arrangement accurately describes the standard entropy values for Na at different phases? Select one: a. Na (g) < Na (s) < Na (l) b. Na (l) < Na (g) < Na (s) c. Na (s) < Na (l) < Na (g) d. Na (s) < Na (g) < Na (l) - Answer c. Na (s) < Na (l) < Na (g) What element has been oxidized and what element has been reduced in the redox reaction shown? 3CuS + 8HNO3 ==> 3CuSO4 + 8NO + 4H20 Select one: a. Copper has been oxidized; nitrogen has been reduced. b. Nitrogen has been oxidized; oxygen has been reduced. c. Sulfur has been oxidized; nitrogen has been reduced. d. Oxygen has been oxidized; copper has been reduced. - Answer c. Sulfur has been oxidized; nitrogen has been reduced. When iron ions react with water, some of the iron ions will combine with water molecules, like this: Fe3+(aq) + 3H2O(l) à Fe(OH)3(s) + 3H+(aq) In this case, is the iron ion acting like an acid or a base? Explain. A. The iron ion is acting like a base. It is forcing water to give up a hydronium ion, which agrees with the Brønsted-Lowry definition of an acid. B. The iron ion is acting like an acid. It has accepted a pair of electrons from the oxygen, which agrees with the Lewis definition of an acid. C. The iron is not acting like either an acid or a base. It is a reducing agent because it has been oxidized. D. The iron ion is acting like an acid. It is removing hydroxide from the solution, which agrees with the Arrhenius definition of an acid. - Answer B. The iron ion is acting like an acid. It has accepted a pair of electrons from the oxygen, which agrees with the Lewis definition of an acid. Ammonia is a vitally important industrial chemical. Fertilizers and nitric acid (an important industrial chemical itself) are produced from ammonia. The Haber-Bosch process is used to create ammonia, and has two major steps: a) CH4(g) + H2O(g) à 2 H2(g) + CO(g) b)3 H2(g) + N2(g) à 2 NH3(g) Is either of these steps an oxidation-reduction reaction? If so, identify which elements are oxidized, which are reduced and which are neither oxidized nor reduced. A. Both of these steps are oxidation-reduction reactions. B. Only reaction b) is an oxidation-reduction reaction. C. Only reaction a) is an oxidation-reduction reaction. D. No, neither of these reactions is an oxidation-reduction reaction. - Answer A. Both of these steps are oxidation-reduction reactions. Calculate Ecell for the galvanic cell based on these half-reactions at 25oC, in which [H2SO4] = 0.5 M HSO4- (aq) + Pb (s) H+ (aq) + PbSO4 (s) + 2 e- Eo = +0.35 V PbO2 (s) + 3H+ (aq) + HSO4- (aq) + 2 e- PbSO4 (s) + 2H2O (l) Eo = +1.46 V If the concentration of sufuric acid is increased, will Ecell increase or decrease? Explain. A. This question cannot be answered with the information given. Concentrations of the other reactants and products are necessary. D. . ΔG°rxn = -0.017 kJ; At standard conditions, acetic acid is less thermodynamically stable than water because it has a more negative value of ΔG°. - Answer A. ΔG°rxn = - 86.0 kJ; At standard conditions, acetic acid is less thermodynamically stable than water because it has a more negative value of ΔG°. Acetylene (properly known as ethyne) and calcium hydroxide are the products of the reaction between calcium carbide (CaC2) and water. Ethyne can be easily set on fire. This can be done on the surface of an ice cube, giving it the appearance of "burning ice". Identify the balanced reaction for the combustion of ethyne and explain why it burns with intense heat. A. 2C2H2 + 5O2 à 4CO2 + 2H2O; There is a lot of energy released in this reaction because there is a triple bond between the carbons in ethyne, which contains a lot of energy, and this energy is released when the bonds are broken. B. C2H4 + 3O2 à 2CO2 + 2H2O; There is a lot of energy released in this reaction because there is a double bond between the carbons in ethyne, which contains a lot of energy, and this energy is released when the bonds are broken. C. C2H4 + 3O2 à 2CO2 + 2H2O; There is a lot of energy released in this reaction because the energy released when forming the chemical bonds in two moles of CO2 and two moles of water H2O is much more than the energy required to break the chemical bonds in one mole of ethyne and three moles of oxygen. D. 2C2H2 + 5O2 à 4CO2 + 2H2O; There is a lot of energy released in this reaction because the energy released when forming the chemical bonds in four moles of CO2 and two moles of water H2O is much more than the energy required to break the chemical bonds in two moles of ethyne and five moles of oxygen. - Answer D. 2C2H2 + 5O2 à 4CO2 + 2H2O; There is a lot of energy released in this reaction because the energy released when forming the chemical bonds in four moles of CO2 and two moles of water H2O is much more than the energy required to break the chemical bonds in two moles of ethyne and five moles of oxygen. In some enzymatic reactions, the product of the reaction that is catalyzed by the enzyme is able to bind to the active site on the enzyme itself. What effect would this have on the activity of the enzyme? Could this be a biologically useful feature in some situations? Explain. A. This would inhibit the enzyme's activity, slowing it down. No, this could not be biologically useful and is the sign of a damaged enzyme. Enzymes should catalyze as many reactions as possible for biological efficiency. B. This would enhance the enzyme's activity, speeding it up. Yes, this could be biologically useful because it would maximize production of the product. C. This would inhibit the enzyme's activity, slowing it down. Yes, this could be biologically useful because it could prevent over-production of the product. D. This would enhance the enzyme's activity, slowing it down. No, this would not be biologically useful because it would cause the enzyme to be less efficient. - Answer C. This would inhibit the enzyme's activity, slowing it down. Yes, this could be biologically useful because it could prevent over- production of the product. Silicon can be "doped" with other elements by adding small amounts of those elements to the silicon. This can make "n-type" or "p-type" semiconductors, depending on what is added to the silicon. What type of semiconductor would be produced by adding indium to silicon? Why? Which element could you add to make the opposite type of semiconductor? A. Doping silicon with indium produces a "p-type" semiconductor. This is because the indium has more protons than silicon, so it is a "p-type" semiconductor. Adding arsenic to silicon would produce an "n-type" semiconductor. B. Doping silicon with indium produces a "n-type" semiconductor. This is because the indium has more neutrons than silicon, so it is an "n-type" semiconductor. Adding arsenic to silicon would produce a "p-type" semiconductor. C. There is not enough information to answer this question. To know what type of semiconductor will be produced requires knowledge of the band-gap energies of each of the elements involved. D. Doping silicon with indium produces a "p-type" semiconductor. This is because the indium has fewer valence electrons than silicon, and this will produce positively charged "holes" in the electron structure. Adding arsenic to silicon would produce an "n-type" semiconductor. - Answer D. Doping silicon with indium produces a "p-type" semiconductor. This is because the indium has fewer valence electrons than silicon, and this will produce positively charged "holes" in the electron structure. Adding arsenic to silicon would produce an "n-type" semiconductor. Atoms that have the same number of protons but different numbers of neutrons are called - Answer Isotopes proposed an atomic theory in 1808. - Answer John Dalton The magnitude of the electron charge was discovered by - Answer R. Millikan E. Rutherford is credited with discovering the - Answer Nucleus Metals and non-metals are separated in the periodic table by a(n) - Answer The two types of close-packing are called cubic close-packing and close- packing. Hexagon al Simple Triangular - Answer Hexagonal Three types of atomic solids are nonbonded, metallic, and . Network covalent Ionic Molecular - Answer Network covalent Effusion is the transfer of gas through a small orifice into an evacuated chamber. - Answer True Kinetic molecular theory is a basic atomic model that describes the behavior of liquids. True False - Answer False Boyle's law is a gas law that associates the product of the pressure and volume with the number of moles, temperature, and a universal proportionality constant. - Answer True Standard temperature and pressure are conditions defined as 0ºC and 1 atm. - Answer True The solubility of ionic compounds in water is mainly determined by forces. Ion-dipole Dipole-dipole Hydrogen-bonded - Answer Ion-dipole An alloy is an example of a solution. - Answer solid-solid A concentration term commonly used for solutions that uses the volume of a solution is . - Answer Molarity The Tyndall effect is the effect whereby a colloidal solution interacts with electricity. True False - Answer False Raoult's law applies to a solution comprised of a non-volatile solute and is the relationship between the vapor pressure of the solution and the vapor pressure of the pure solvent. - Answer True Boiling point elevation is a colligative property that involves the increase in the boiling point of a solvent by the addition of a solute - Answer True Colligative properties are concerned with the type of particles and not their number. - Answer False When a solid is dissolved in water and forms a solution that conducts electricity, the solid is called a(n) . Metal Electrolyte Ion - Answer Electrolyte Two dissolved ions in hard water are Mg2+ and . Na+ Ca2+ Cu2+ - Answer Ca2+ When a solid comes out of a solution, the solid is called a(n) . Precipitate Salt Electrolyte - Answer Precipitate Acid-base reactions are also called reactions. Neutralization Ionic Dipole - Answer Neutralization Who defined an acid as a proton donor and a base as a hydroxide donor? Avogrado Arrhenius Bohr - Answer Arrhenius A reaction where electrons are transferred from one reactant to another is called a(n) reaction. Redox or oxidation- reduction Acid-base Ionic - Answer Redox or oxidation-reduction Acid-base model Ionic model - Answer Crystal field model is a trend that describes ligands from strong field to weak field. Electronegativity The spectrochemical series The crystal field model - Answer The spectrochemical series A coordination environment where a metal is surrounded by six ligands is called . Linear Tetrahedral Octahedral - Answer Octahedral A reduction in atomic radii caused by the 4f electrons being close to the nucleus is called . Lanthanide contraction Disproportionation Spectrochemical series - Answer Lanthanide contraction A ligand that forms one bond to the metal is called a(n) . Ionic bond Unidentate Covalent bond - Answer Unidentate What are the two particles that compose the nucleus? - Answer Neutrons and Protons Isotope - Answer Atoms of the same element that have different numbers of neutrons Charge of a proton - Answer positive charge of a neutron - Answer neutral charge of electron - Answer negative Protons and electrons are... - Answer equal derived unit - Answer A unit defined by a combination of SI units Proposed the Atomic Theory in 1803 - Answer John Dalton Discovered the nucleus - Answer Ernest Rutherford Discovered magnitude of the electron charge - Answer R. Millikan Pauli Exclusion Principle - Answer Two electrons in the same orbital must have opposite spins valence electrons - Answer Electrons on the outermost energy level of an atom Stable nuclei have , , , , , protons - Answer 2, 8, 20, 50, 82, 126 Element essential for plant growth - Answer potassium S Block Element - Answer Most main group elements P Block - Answer Most nonmetallic elements Kelvin = C + - Answer 273.15 Density = - Answer Mass/Volume Scientific Method - Answer Observations give rise to laws, data give rise to hypotheses, hypotheses are tested with experiments, and successful hypotheses give rise to theories. Number of known elements - Answer 118, 94 natural Units of Length - Answer meter Units of Mass - Answer kilograms Units of time - Answer seconds Units of Temperature - Answer Kelvin Amount of substance - Answer mole Acids are compounds that dissolve in water to produce - Answer protons Bases are compounds that dissolve in water to produce - Answer hydroxide ions Strong Acids - Answer HCl, HBr, HI, HNO3, H2SO4, HClO4, HClO3, HSO4 Mass of Electron - Answer charge/(charge/mass) Cl atom (atomic number 17) has ____________protons & electrons - Answer 17 and 17 Cl- atom (atomic number 17) has protons and electrons - Answer 17 and 18 Element+ = - Answer Minus one electron Element- = - Answer plus one electron Group 1A elements have what charge? - Answer 1+ Group 2A elements have what charge? - Answer 2+ Group 3A elements have what charge? - Answer 3+ Group 4A elements have what charge? - Answer 4- Group 5A elements have what charge? - Answer 3- Group 6A elements have what charge? - Answer 2- Group 7A elements have what charge? - Answer 1- Zinc Iodide formula: Zn2+ + I- - Answer ZnI2 (Zn has a charge of 2+ and I has a charge of 1-. To get 2- to even out the charge, we need two Iodide ions) If a cation and anion have different values in their charge, what do you do for the formula? - Answer Swap the charge numbers and put them as subscripts. Mono = - Answer 1 Di = - Answer 2 Tri = - Answer 3 Tetra = - Answer 4 Penta = - Answer 5 What is the name of NF3? - Answer Nitrogen Trifluoride What is the name of N2O4 - Answer Dinitrogen Tetroxide What is the molecular formula for carbon disulfide? - Answer