Answer Sheet. CHM 080 Spring 2012 K. Young Practice Exam #

Transcription

1 1 Answer Sheet Name Each question is worth 1 point, the entire exam will be scaled up to 100 points total (e.g. all 78 correct = 100 points). You may use your cheat sheet, your calculator, the periodic table, and, of course, your brain!

2 2 Multiple Choice 1) Calcium carbonate (CaCO3) is 34.5% Ca by mass. In a 418 g sample of CaCO3, how many grams of calcium are present? A) 144 g B) g C) g D) 83.6 g Topic: Section 3.1 2) According to the experiments of Ernest Rutherford, where can a majority of a given atom's mass be found? A) scattered randomly throughout an approximately cube-shaped atom B) at the center of an approximately spherical atom C) in concentric layers of spherical shape D) as small pieces orbiting a common center in circular paths Topic: Section 3.3 3) How many neutrons does the nucleus of the phosphorus-32 isotope have? A) 15 B) 16 C) 17 D) 32 4) What is the atomic number of uranium-235? A) 235 B) 238 C) 92 D) 143 5) A 3.45 gram sample of hematite (Fe2O3) that contains 2.41 grams of Fe has what percentage Fe by mass? A) 40% B) 30% C) 70% D) 60% 6) How is the term "atomic number" defined for a given atom or isotope? A) as the mass of one mole of that element or isotope B) as the sum of the protons, neutrons, and electrons it contains C) as the sum of the protons and neutrons its nucleus contains D) as the number of protons its nucleus contains 7) A neutral atom's atomic number is equal to. A) the number of nucleons B) the sum of protons and neutrons C) the number of electrons D) the number of neutrons 8) What element does X represent the symbol X? A) zinc B) iron

3 3 C) iridium D) cesium E) manganese 9) What element does X represent the symbol X? A) silver B) gold C) bohrium D) cobalt E) neodymium 10) Which of the following terms applies to the vertical columns found on a periodic table? A) Arrangement B) Group C) Period D) Isotope 11) Which of the following terms applies to the horizontal rows found on a periodic table? A) Arrangement B) Group C) Period D) Isotope 12) What name is commonly given to the elements of Group IA of the periodic table? A) Alkaline earth metals B) Transition metals C) Platinum metals D) Alkali metals 13) Which of the following is a metalloid in the third period of the periodic table? A) Al B) Si C) P D) S 14) Which of the following elements is a chalcogen? A) H B) N C) O D) F 15) Which of the following is a transition element? A) Co B) Eu C) Es D) He

4 4 16) Which element, isotope, or ion listed below contains 16 protons, 17 neutrons, and 18 electrons? A) 33Ar2- B) 33S2- C) 33Cl D) 34S2-17) Which of the following elements may have a cation that has 16 electrons? A) Si B) P C) S D) Cl 18) Which of the following elements can have an anion with 18 electrons? A) Cl B) Ar C) Sc D) Fe 19) Which of the following has the highest ionization energy? A) O B) Sn C) As D) C 20) How many electrons are found in a Fe3+ ion? A) 23 B) 26 C) 29 D) 56 21) Which of the following has more electrons than neutrons? A) 24Mg+2 B) 27Al C) 75As-3 D) 32S-2 22) Which of the following pairs are isotopes? A) Ca+2 and Mg+2 B) 199Hg and 200Hg C) 18O and 19F D) 238U and 238Np 23) Which cation may have atomic number 20 and a charge of +2? A) C+2 B) Mg+2 C) Ca+2

5 5 D) S+2 True/False 24) The conservation of mass law states that matter can neither be created nor destroyed during a chemical reaction. Topic: Section ) The law of multiple proportions can be used to explain why it is possible that both CO and CO2 can exist, differing only in their carbon-to-oxygen ratios Topic: Section ) A neutral atom of the isotope phosphorus-32 contains 15 protons, 17 neutrons, and 15 electrons. 27) The oxygen-17 isotope has more protons than neutrons in its nucleus. 28) The amu for an atom is the weighted average of all the naturally occurring isotopes. 29) Group IIA of the periodic table contains elements that are gaseous non-metals. 30) Radium is the only noble gas that is radioactive. 31) Iodine is the only non-metal that is a solid at room temperature. 32) The most stable isotope of oxygen has 8 neutrons. 33) One needs to supply energy from an outside source to form a cation from a neutral atom. Short Answer Write the atomic symbols for the following neutral isotopes. 34) lead-207

6 6 35) uranium-235 Matching Match every element with its symbol from the list below. A) Ni B) Po C) Ag D) Rn E) K F) Ra G) Au H) N I) Si J) Na K) Pa L) Mn M) S N) Mg O) Cu P) Co Q) P 36) Sulfur 37) Potassium 38) Manganese 39) Magnesium 40) Radium 41) Radon 42) Nitrogen 43) Nickel 44) Polonium

7 7 45) Protactinium 46) Sodium 47) Silver 48) Silicon 49) Phosphorus 50) Gold 51) Copper 52) Cobalt Match the scientist with his contribution to the chemistry field from the list below. A) Proved that matter is always conserved B) Demonstrated the existence of the neutron C) Believed that the matter could be infinitely subdivided D) Rationalized that matter is neither created nor destroyed E) Discovered the electron F) Discovered (with Thomson) the proton G) Constructed the periodic table H) Postulated that matter is made up of tiny atoms 53) Antoine Lavoisier 54) Democritus 55) Aristotle 56) Dmitri Mendeleev 57) John Dalton 58) J.J. Thomson 59) James Chadwick

8 8 60) E. Goldstein Match every element with an occurrence from the list below. A) Pop cans B) Bicycle Frames C) Steel D) Diamonds E) Computer Chips F) Thermometers G) Plating car bumpers H) Antacids 61) Silicon 62) Chromium 63) Magnesium 64) Carbon 65) Iron 66) Mercury 67) Titanium 68) Aluminum Match each statement in the questions with the correct species from the list below. A) 23Na+ B) 7Be C) 4He+ D) 12C E) 35C1- F) 1H or 1H+ G) 1H+ H) 3H I) 27A1 J) 30p

9 9 69) Has a mass number equal to 27 70) Has ten electrons 71) Has a nuclear charge of ) Has an equal number of protons, neutrons, and electrons 73) Has no neutrons 74) Has a number of electrons equal to that of neutrons, but different than that of protons 75) Has no electrons 76) Has a number of neutrons (other than zero) which is less than the number of protons 77) Has a number of neutrons twice that of protons 78) Has a number of neutrons twice that of electrons