Name: Period: Date: KIPP NYC College Prep General Chemistry Quarter 1: Let s Review Multiple Choice Do Now! 1. Which substance can be decomposed by chemical means? (1) Aluminum (2) Octane (3) Silicon (4) Xenon 2. Which substance can not be broken down by a chemical change? (1) Ammonia (2) mercury (3) propane (4) water 3. Which pair is classified as pure substances? (1) mixtures and solutions (2) compounds and solutions (3) elements and mixtures (4) compounds and elements 4. When sugar is dissolved in water, the resulting solution is classified as a (1) homogeneous mixture (2) heterogeneous mixture (3) homogeneous compound (4) heterogeneous compound 5. Which list of formulas represent compounds, only? (1) CO 2, H 2O, NH 3 (2) H 2, N 2, O 2 (3) H 2, Ne, NaCl (4) MgO, NaCl, O 2 6. A student is filtering a mixture of sand, salt, and water into a cup. What will be found in the cup after the filtration is completed? (1) sand, only (2) salt, only (3) sand and salt (4) salt and water 7. Which statement best describes the molecules of AlCl 3 (s)? (1) They move slowly in straight lines (2) They move rapidly in straight lines (3) They are arranged in a random pattern (4) They are arranged in a regular pattern 8. Which set of properties does a substance such as CO 2 (g) have? (1) definite shape and definite volume (2) definite shape but no definite volume (3) no definite shape but definite volume (4) no definite shape and no definite volume 9. Which statement describes a chemical property of the element magnesium? (1) Magnesium is malleable. (2) Magnesium conducts electricity. (3) Magnesium reacts with an acid. (4) Magnesium has a high boiling point. 10. An example of a physical property is the element s ability to (1) react with an acid (2) react with oxygen (3) form a compound with chlorine (4) form an aqueous solution 11. The mass of a proton is approximately equal to the mass of (1) an alpha particle (2) an electron (3) a neutron (4) a positron
12. Which subatomic particles are located in the nucleus of an He-4 atom? (1) Electrons and neutrons (2) Electrons and protons (3) Neutrons and protons (4) Neutrons, protons, and electrons 13. What is the total number of neutrons in an atom of C-13? (1) 13 (2) 7 (3) 6 (4) 1 14. What is the charge of an ion that has 6 protons, 7 neutrons, and 4 electrons? (1) +2 (2) +1 (3) 0 (4) -1 15. An atom of any element must contain (1) An equal number of protons and neutrons (2) An equal number of protons and electrons (3) More electrons than neutrons (4) More electrons than protons 16. The mass of a proton is approximately equal to the mass of (5) an alpha particle (6) an electron (7) a neutron (8) a positron 17. Which electron configuration represents the electrons of an atom in an excited state? [1] (1) 2-1 (3) 2-8-7 (2) 2-7-4 (4) 2-4 18. What is the total number of electrons in the valence shell of an atom of aluminum in the ground state? (1) 8 (2) 2 (3) 3 (4) 10 19. What is the total number of electrons in a Cr 3+ ion? (1) 18 (2) 21 (3) 24 (4) 27
Matter Element Compound Mixture Atoms Plum Pudding Rutherford Bohr Model Electrons Bright Line Spectra for Mixture Lewis Structure Li Bohr Model Li in an Excited State
Cereal Box Review! Arrange the pieces of the cereal box to answer the questions. Then turn the pieces over. If you are correct, the cereal box should be in the right order! Box Top #1: Models of the atom! Match the name of the model with the description and place them in the correct order! Bohr Rutherford Dalton Thompson Wave-Mechanical Electrons in orbitals Plum-pudding (chocolate chip cookie) Nucleus with empty space Hard-sphere Electrons in shells (orbits) Finished box: 1) Dalton == hard-sphere 2) Thompson == plum-pudding 3) Rutherford == Nucleus with empty space 4) Bohr == electrons in shells (orbits) 5) Wave-Mechanical == Electrons in orbitals Box Top #2: Subatomic Particles Match the description with the correct subatomic particle. Each subatomic particle is used 3 times and are numbered by their order. 1. Has a charge of -1 Electrons 1 2. Has no effect on charge. Neutrons 1 3. Is different in different isotopes Neutrons 2 4. Affects charge and mass of atom Protons 1 5. Does not affect the mass Electrons 2 6. Affects mass of atom only Neutrons 3 7. Always equals the atomic number Protons 2 8. Makes the nucleus positive Protons 3 9. Can be lost or gained for ions Electrons 3
Box Top #3: Classification of Matter Match the description with the correct classification of matter 1. Consists of one type of atom Element 2. Two same atoms chemically combine Diatomic Element 3. A substance that can be separated physically Mixture 4. Filtration best separates this mixture Heterogeneous Mixture 5. This mixture is evenly dispersed Homogeneous Mixture 6. These particles have no volume and no shape gases 7. Can be decomposed through chemical change compound 8. Distillation separates mixtures of this state best liquids 9. These particles are packed tightly together solids Box Top #4: Electrons Match the statement of the electron with the correct number(s) 1. Ground state for Aluminum 2-8-3 2. Charge of ion from Group 2 atom +2 3. Change in # of electrons for Group 1 ions -1 4. Charge of ion from Group 16 atom -2 5. Octet number of valence electrons. 8 6. Excited state for Aluminum 2-7-4 7. Change in # of electrons for Group 17 ions +1 8. Electron configuration for Al 3+ 2-8
Free Response and Math! Part I Use the picture on the right to answer the following questions: 1. Which diagram depicts only one compound composed of atoms of element X and element Z? 3 2. Which diagram depicts a mixture of diatomic elements X and element Z? 1 3. Which diagram depicts a mixture that contains different compounds of element X and element Z?4 4. In an investigation, a dripless wax candle is massed and then lighted. As the candle burns a small amount of liquid wax forms near the flame. After 10 minutes, the candle s flame is extinguished and the candle is allowed to cool. The cooled candle is massed. a) Identify one physical change that takes place in this investigation. Candle melts b) State one observation that indicates a chemical change has occurred in this investigation. Wick burns! 5. Explain, in terms of protons and neutrons, why U-235 and U-238 are different isotopes of uranium. [1] Protons: same Neutrons: U-238 has 3 more neutrons c) Copper has two naturally occurring isotopes. Information about the two isotopes is shown in the table below. 6. In the space below, show a numerical setup for calculating the atomic mass of copper. [1] In the gold foil experiment, a thin sheet of gold was bombarded with alpha particles. Almost all the alpha particles pass straight through the foil. Only a few alpha particles were deflected from their original path. = (62.93 x 0.6917 + (64.93 x 0.3083)
Free Response and Math! Part II 7. State one conclusion about atomic structure based on the observation that almost all alpha particles passed straight through the foil. [1] The atom is mostly empty space. 8. Explain, in terms of charged particles, why some of the alpha particles were deflected. [1] The nucleus was positively charged. In the early 1800s, John Dalton proposed an atomic theory that was based on experimental observations made by several scientists. Three concepts of Dalton s atomic theory are stated below. Statement A: Atoms are indivisible and cannot be destroyed or broken down into smaller parts. Statement B: Atoms of one element cannot be changed into atoms of another element. Statement C: All atoms of one element have the same mass. 9. Explain, in terms of particles, why statement A is no longer accepted. [1] Atoms can be broken into protons, neutrons and electrons 10. Explain, in terms of particles in the atoms of an element, why statement C is false. [1] Isotopes can be the same elements with different numbers of neutrons and masses. 11. Explain why an atom is considered to be neutral in charge but the nucleus of an atom is positively charge. [1] The atom has equal protons, which are positive, and electrons, which are negative. The nucleus is positive because it only contains protons, which are positive, and neutrons, which have no charge. 12. Explain why the atomic mass only accounts for protons and neutrons. [1] The electrons have very little mass 0 amu. Protons and neutrons each have a mass of 1 amu. 13. Explain, in terms of atomic structure, why the noble gas neon is an unreactive element. [1] The noble gas has 8 valence electrons. 14. Explain, in terms of both electrons and energy, how the bright-line spectrum of an element is produced. [1] An element absorbs energy and electrons move to an excited state. When the electrons return to the ground state, energy in the form of light is released. 15. If an object has a mass of 3.0 grams and has a volume of 2 ml (2 cm 3 ), when what is the density of the object? 3.0g / 2 cm3 = 1.5 g/cm3