Red Hook Central High School. Honors CHEMISTRY. Midterm Examination. Thursday, January 25, :30 to 2:30 p.m., only. Notice...

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1 Red Hook Central High School Honors CHEMISTRY Midterm Examination Thursday, January 25, :30 to 2:30 p.m., only This is a test of your knowledge of chemistry. Use that knowledge to answer all questions in this examination. Some questions may require the use of the Reference Tables for Physical Setting/Chemistry. You are to answer all questions in all parts of this examination according to the directions provided in the examination booklet. The answers to all questions in this examination are to be written in your separate answer booklet. Be sure to fill in the heading on the front of your answer booklet. All work should be written in pen, except for graphs and drawings, which should be done in pencil. You may use scrap paper to work out the answers to the questions, but be sure to record all your answers in your answer booklet. When you have completed the examination, you must sign the statement printed on the first page of your answer booklet, indicating that you had no unlawful knowledge of the questions or answers prior to the examination and that you have neither given nor received assistance in answering any of the questions during the examination. Your answer booklet cannot be accepted if you fail to sign this declaration. Notice... A four-function or scientific calculator and a copy of the Reference Tables for Physical Setting/Chemistry must be available for you to use while taking this examination. The use of any communications device is strictly prohibited when taking this examination. If you use any communications device, no matter how briefly, your examination will be invalidated and no score will be calculated for you. DO NOT OPEN THIS EXAMINATION BOOKLET UNTIL THE SIGNAL IS GIVEN.

2 Part A Answer all questions in this part. Directions (1 30): For each statement or question, fill in on your answer sheet the number of the word or expression that, of those given, best completes the statement or answers the question. Some questions may require the use of the Reference Tables for Physical Setting/Chemistry. 1 A neutron has a charge of (1) (3) 0 (2) (4) 2 Which particle has the least mass? (1) atom (3) neutron (2) electron (4) proton 3 A sample of matter must be copper if (1) each atom in the sample has 29 protons (2) atoms in the sample react with oxygen (3) the sample melts at 1768 K (4) the sample can conduct electricity 4 In the electron cloud model of the atom, an orbital is defined as the most probable (1) charge of an electron (2) conductivity of an electron (3) location of an electron (4) mass of an electron 5 The elements on the Periodic Table are arranged in order of increasing (1) atomic number (2) mass number (3) number of isotopes (4) number of moles 6 Which element has the highest melting point? (1) tantalum (3) osmium (2) rhenium (4) hafnium 8 A student determined the percentage of water of hydration in BaCl 2 2H 2 O to be 15.79%. The accepted percentage is 14.75%. What is the student s percent error? (1) 1.04 % (2) 6.00 % (3) 6.59 % (4) 7.05 % 9 The gram-formula mass of a compound is 48 grams. The mass of 1.0 mole of this compound is (1) 1.0 g (3) 48 g (2) 4.8 g (4) 480 g 10 Given the balanced equation representing a reaction: Cl 2 Cl Cl What occurs during this reaction? (1) A bond is broken as energy is absorbed. (2) A bond is broken as energy is released. (3) A bond is formed as energy is absorbed. (4) A bond is formed as energy is released. 11 Which atom has the weakest attraction for the electrons in a bond with an H atom? (1) Cl atom (3) O atom (2) F atom (4) S atom 12 Which substance can not be broken down by a chemical change? (1) ammonia (3) propane (2) mercury (4) water 7 What is the total number of electron pairs shared between the two atoms in an O 2 molecule? (1) 1 (3) 6 (2) 2 (4) 4

3 13 Which ionic compound dissolves in water to form a colored solution? (1) Ca(NO 3 ) 2 (2) Ca(NO 3 ) 2 (3) KNO 3 (4) Al(NO 3 ) 3 14 Which sample contains the same number of atoms as one gram of He? (1) 6 g of C (2) 7 g of Li (3) 10 g of Ar (4) 36 g of Be 15. Which compound has hydrogen bonding between its molecules? (1) CH 4 (2) CaH 2 (3) KH (4) NH Which list of elements contains a metal, a metalloid, a nonmetal, and a noble gas? (1) Be, Si, Cl, Kr (3) K, Fe, B, F (2) C, N, Ne, Ar (4) Na, Zn, As, Sb 17. A molecular compound is formed when a chemical reaction occurs between atoms of (1) chlorine and sodium (2) chlorine and yttrium (3) oxygen and hydrogen (4) oxygen and magnesium 18. Which statement describes the general trends in electronegativity and metallic properties as the elements in Period 2 are considered in order of increasing atomic number? (1) Both electronegativity and metallic properties decrease. (2) Both electronegativity and metallic properties increase. (3) Electronegativity decreases and metallic properties increase. (4) Electronegativity increases and metallic properties decrease. 19. Which electron configuration represents the electrons of an atom in an excited state? (1) 2-1 (3) (2) (4) Which balanced equation represents a single replacement reaction? (1) Mg 2AgNO 3 Mg(NO 3 ) 2 2Ag (2) 2Mg O 2 2MgO (3) MgCO 3 MgO CO 2 (4) MgCl 2 2AgNO 3 2AgCl Mg(NO 3 ) 2 21 If an element, X, can form an oxide that has the formula X 2 O 3, then element X would most likely be located on the Periodic Table in the same group as (1) Ba (3) In (2) Cd (4) Na 22 In which material are the particles arranged in a regular geometric pattern? (1) CO 2(g) (3) H 2 O (l) (2) NaCl (aq) (4) C 12 H 22 O 11(s)

4 23 The sum of the atomic masses of the atoms in one molecule of C 3 H 6 Br 2 is called the (1) formula mass (2) isotopic mass (3) percent abundance (4) percent composition 24 What is the total number of neutrons in an atom of O- 18? (1) 18 (3) 10 (2) 16 (4) 8 25 What is the total number of electrons in a Cu + ion? (1) 28 (3) 30 (2) 29 (4) According to Table F, which compound is soluble in water? (1) barium phosphate (3) silver iodide (2) calcium sulfate (4) sodium perchlorate 29 Which process is a chemical change? (1) melting of ice (2) boiling of water (3) subliming of ice (4) decomposing of water 30 Which substance contains bonds that involved the transfer of electrons from one atom to another? (1) CO 2 (3) KBr (2) NH 3 (4) Cl 2 26 Which formula represents a polar molecule? (1) H 2 (3) CO 2 (2) H 2 O (4) CCl 4 27 Which formula represents a molecule having a nonpolar covalent bond?

5 Part B 1 Answer all questions in this part. Directions (31 50): For each statement or question, fill in on your answer sheet the number of the word or expression that, of those given, best completes the statement or answers the question. Some questions may require the use of the Reference Tables for Physical Setting/Chemistry. 31 Compared to the atoms of nonmetals in Period 3, the atoms of metals in Period 3 have (1) fewer valence electrons (2) more valence electrons (3) fewer electron shells (4) more electron shells 32 Which elements are malleable and good conductors of electricity? (1) iodine and silver (3) tin and silver (2) iodine and xenon (4) tin and xenon 33 Which atom in the ground state requires the least amount of energy to remove its valence electron? (1) lithium atom (3) rubidium atom (2) potassium atom (4) sodium atom 34 What is the chemical formula of iron (III) sulfide? (1) FeS (3) FeSO 3 (2) Fe 2 S 3 (4) Fe 2 (SO 3 ) 3 35 What is the percent composition by mass of sulfur in the compound MgSO 4 (gram-formula mass = 120. grams per mole)? (1) 20.% (3) 46% (2) 27% (4) 53% 36 Which element has chemical properties that are most similar to the chemical properties of sodium? (1) beryllium (3) lithium (2) calcium (4) magnesium 37 When the equation Al 2 (SO 4 ) 3 + ZnCl 2 AlCl 3 + ZnSO 4 Is correctly balanced using smallest whole number coefficients, the sum of the coefficients is? (1) 4 (3) 8 (2) 5 (4) 9 38 Given two formulas representing the same compound: Formula A Formula B CH 3 C 2 H 6 Which statement describes these formulas? (1) Formulas A and B are both empirical. (2) Formulas A and B are both molecular. (3) Formula A is empirical, and formula B is molecular. (4) Formula A is molecular, and formula B is empirical. 39 Given the balanced equation representing a reaction: ZnSO 4(aq) + H 2 CO 3(aq) ZnCO 3(s) + H 2 SO 4(aq) Which type of reaction is represented by this equation? (1) decomposition (3) single replacement (2) double replacement (4) synthesis 40 In a laboratory where the air temperature is 22 C, a steel cylinder at 100. C is submerged in a sample of water at 40. C. In this system, heat flows from (1) both the air and the water to the cylinder (2) both the cylinder and the air to the water (3) the air to the water and from the water to the cylinder (4) the cylinder to the water and from the water to the air

6 41 Which diagram represents a physical change, only? 42 During a laboratory activity to investigate reaction rate, a student reacts 1.0-gram samples of solid zinc with 10.0-milliliter samples of HCl (aq). The table below shows information about the variables in five experiments the student performed. Which two experiments can be used to investigate the effect of the concentration of HCl (aq) on the reaction rate? (1) 1 and 3 (3) 4 and 2 (2) 1 and 5 (4) 4 and 3

7 43 Which type of bond is found between atoms of solid cobalt? (1) nonpolar covalent (3) metallic (2) polar covalent (4) ionic 44 A 36-gram sample of water has an initial temperature of 22 C. After the sample absorbs 1200 joules of heat energy, the final temperature of the sample is (1) 8.0 C (3) 30. C 48 Which sample of matter can be separated into different substances by physical means? (1) LiCl (aq) (3) NH 3(g) (2) LiCl (s) (4) NH 3(l) 49 Which Lewis electron-dot diagram represents an atom in the ground state for a Group 13 element? (2) 14 C (4) 55 C 45 Which statement explains why Br 2 is a liquid at STP and I 2 is a solid at STP? (1) Molecules of Br 2 are polar, and molecules of I 2 are nonpolar. (2) Molecules of I 2 are polar, and molecules of Br 2 are nonpolar. (3) Molecules of Br 2 have stronger intermolecular forces than molecules of I A sample of an element has a mass of grams and a volume of 3.8 cubic centimeters. To which number of significant figures should the calculated density of the sample be expressed? (1) 5 (3) 3 (2) 2 (4) 4 (4) Molecules of I 2 have stronger intermolecular forces than molecules of Br Which sample of ethanol has particles with the highest average kinetic energy? (1) 10.0 ml of ethanol at 25 C (2) 10.0 ml of ethanol at 55 C (3) ml of ethanol at 35 C (4) ml of ethanol at 45 C 47 Which equation represents sublimation? (1) I 2(s) I 2(g) (3) I 2(l) I 2(g) (2) I 2(s) I 2(l) (4) I 2(l) I 2(s)

8 Part B 2 Answer all questions in this part. Directions (51 65): Record your answers in the spaces provided in your answer booklet. Some questions may require the use of the Reference Tables for Physical Setting/Chemistry. 51 Explain, in terms of protons and neutrons, why U-235 and U-238 are different isotopes of uranium. [1] Base your answers to questions 52 through 54 on the information below. The bright-line spectra for three elements and a mixture of elements are shown below. 52 Explain, in terms of sub atomic particles, energy levels, and energy transitions, how the bright-line spectrum of an element is produced. [1] 53 Identify all the elements in the mixture. [1] 54 Write the detailed electron configuration of a cadmium atom in the ground state (1s 2, ). [1]

9 Base your answers to questions 55 through 59 on the information below. The ionic radii of some Group 2 elements are given in the table below. 55 On the grid in your answer booklet, mark an appropriate scale on the axis labeled Ionic Radius (pm). [1] 56 On the same grid, plot the data from the data table. Circle and connect the points. [1] 57 Estimate the ionic radius of strontium using your graph. [1] 58 State the trend in ionic radius as the elements in Group 2 are considered in order of increasing atomic number. [1] 59 Explain, in terms of electrons, why the ionic radius of a Group 2 element is smaller than its atomic radius. [1] Base your answers to questions 60 through 64 on the chemical equation below. KClO 3(s) KCl (s) O 2(g) 60 Balance the equation. [1] 61 What type of reaction is represented by this equation? [1] 62 Give the IUPAC name for the reactant in this equation. [1] 63 Determine the oxidation number of chlorine in the reactant in the equation. [1] 64 The reaction above is endothermic. If the term + energy were to be added to the equation, what side of the reaction would it be added to? [1]

10 Base your answers to question 65 on the information below. A 2.0-liter aqueous solution contains a total of 3.0 moles of dissolved NH 4 Cl at 25 C and standard pressure. 65 Identify the two ions present in the solution resulting from dissolving NH 4 Cl in water. [1]

11 Part C Answer all questions in this part. Directions (66 83): Record your answers in the spaces provided in your answer booklet. Some questions may require the use of the Reference Tables for Physical Setting/Chemistry. Base your answers to question 66 on the information below. Natural gas is a mixture that includes butane, ethane, methane, and propane. Differences in boiling points can be used to separate the components of natural gas. The boiling points at standard pressure for these components are listed in the table below. 66 List the four components of natural gas in order of increasing strength of intermolecular forces. [1] Base your answers to questions 67 through 70 on the information below. In 1864, the Solvay process was developed to make soda ash. One step in the process is represented by the balanced equation below. NaCl + NH 3 + CO 2 + H 2 O NaHCO 3 + NH 4 Cl 67 Write the chemical formula for one compound in the equation that contains both ionic bonds and covalent bonds. [1] 68 Explain, in terms of electronegativity difference, why the bond between hydrogen and oxygen in a water molecule is more polar than the bond between hydrogen and nitrogen in an ammonia molecule. [1] 69 In the space in your answer booklet, draw a Lewis electron-dot diagram for the reactant containing carbon in the equation. [1] 70 In the space in your answer booklet, draw a Lewis electron-dot diagram for the reactant containing sodium in the equation. [1]

Base your answers to questions 71 through 73 on the information below. A student prepared two mixtures, each in a labeled beaker. Enough water at 20.

[1] 72 Determine the volume of the Fe filings used to produce mixture 2. Round your answer to the correct number of significant figures.

12 Base your answers to questions 71 through 73 on the information below. A student prepared two mixtures, each in a labeled beaker. Enough water at 20. C was used to make 100 milliliters of each mixture. 71 Classify each mixture using the term homogeneous or the term heterogeneous. [1] 72 Determine the volume of the Fe filings used to produce mixture 2. Round your answer to the correct number of significant figures. [1] 73 Describe a procedure to physically remove the water from mixture 1. [1] 74 Copper has two naturally occurring isotopes. Information about the two isotopes is shown in the table below. In the space in your answer booklet, show a numerical setup for calculating the atomic mass of copper. [1]

13 Base your answers to questions 75 through 77 on the information below. In an experiment, 2.54 grams of copper completely reacts with sulfur, producing 3.18 grams of copper(i) sulfide. 75 Determine the total mass of sulfur consumed. [1] 76 Draw the orbital notation of an atom of sulfur in the ground state. [1] 77 Write the chemical formula of the compound produced. [1] Base your answers to questions 78 through 80 on the information below. A tablet of one antacid contains citric acid, H 3 C 6 H 5 O 7, and sodium hydrogen carbonate, NaHCO 3. When the tablet dissolves in water, bubbles of CO 2 are produced. This reaction is represented by the incomplete equation below. H 3 C 6 H 5 O 7(aq) 3NaHCO 3(aq) Na 3 C 6 H 5 O 7(aq) 3CO 2(g) 3 (l) 78 Complete the equation in your answer booklet by writing the formula of the missing product. [1] 79 State evidence that a chemical reaction occurred when the tablet was placed in the water. [1] 80 Determine the total number of moles of sodium hydrogen carbonate that will completely react with mole of citric acid. [1] Base your answers to question 81 on the information below. John Dalton was an English scientist who proposed that atoms were hard, indivisible spheres. In the modern model, the atom has a different internal structure. 81 a Identify one experiment that led scientists to develop the modern model of the atom. [1] b Describe this experiment. [1] c State one conclusion about the internal structure of the atom, based on this experiment. [1]

14 82 Calculate the gram formula mass of Na 3 PO 4. Round atomic masses from the periodic table to the nearest tenth and record your answer to the correct number of significant figures. [1] 83 What is the mass of 4.76 moles of Na 3 PO 4? [1]

15 Red Hook Central High School HONORS CHEMISTRY Midterm Examination Thursday, January 25, :30 to 2:30 p.m., only

18 KClO 3(s) KCl (s) O 2(g)

Name: 1. The mass of a proton is approximately equal to the mass of (1) an alpha particle (2) a beta particle (3) a positron (4) a neutron

Name: 1. The mass of a proton is approximately equal to the mass of (1) an alpha particle (2) a beta particle (3) a positron (4) a neutron Chemistry Section Name: MID TERM STUDY GUIDE Date: A. Multiple Choice. 1. The mass of a proton is approximately equal to the mass of (1) an alpha particle (2) a beta particle (3) a positron (4) a neutron