Unit 2 Review - 2016 Topics Covered: % mass (MOE/MOC x 100) Alloy Atoms Atomic mass Average atomic mass Atomic number Basic mixture Chemical property Chemical reaction Colloid Compound Distillation Element Electrons Gas Heterogeneous mixture Homogeneous Mixture Isotopes Isotopic symbols Law of conservation of mass Law of definite proportions Liquid Mass number Mass Mass # Matter Mixture Neutrons Protons Physical change Physical property Product Reactant Solid Solution Substance Suspension Tyndall effect Examples: Atomic # 9 Mass # # protons 14 47 55 # neutrons 10 15 25 # electrons Symbol 25 Fill in the table: Particle Proton Neutron Electron Charge Mass FROM HERE ON, SHOW ALL WORK ON A SEPARATE SHEET OF PAPER!!!!!!!!!! 1. Calculate the approximate atomic mass for lead using the following info ( note: 1 p + = 1.007276 amu, and 1 n0 = 1.008664 amu) 82 p 122 n 1.37% 82 p 124 n 26.26% 82 p 125 n 20.82% 82 p 126 n 51.55% 2. Which subatomic particle identifies an atom as that of a particular element? 3. Copper has two isotopes Cu-63 (abundance = 69.2%, mass = 62.930 amu) and Cu-65 (abundance = 30.8%, mass = 64.928 amu). Calculate the atomic mass – SHOW WORK!! 4. Show the isotopic symbols for each isotope mentioned in the question above. 5. Why is an element electrically neutral? 6. How can there be 1000 different atoms when there are only about 100 different elements? 7. What is the difference between the mass number and the atomic number of an atom? 8. Identify the following matter as substances or mixtures. Then identify each as an element, compound, homogeneous, or heterogeneous mixture. Then JUSTIFY your answer. A B C D 9. What state of matter do each of the following diagrams represent? JUSTIFY your answer. A B C 10. Explain the law of conservation of mass. 11. In the complete reaction of 22.99 g of sodium with 35.45 g of chlorine, what mass of sodium chloride is formed? SHOW ALL WORK 12. A 12.2 g sample of X reacts with a sample of Y to form 78.9 g XY. What is the mass of Y that reacted? SHOW ALL WORK 13. Describe the structure of a typical atom. Identify where each subatomic particle is located. 14. Describe the separation technique that could be used to separate the following mixtures. a. Two colorless liquids with different polarities/attractive forces for mobile phase of a liquid. b. Salt dissolved in water c. Two substances that form a heterogeneous suspension with a solid. 15. Classify each of the following as a chemical or physical property a. Iron and oxygen form rust b. Iron is more dense than aluminum c. Magnesium burns brightly when ignited d. Oil and water do not mix e. Mercury melts at -39 degrees Celsius 16. Classify each example as a physical or a chemical change a. Crushing an aluminum can b. Aluminum combining with oxygen to form aluminum oxide c. Leaves changing color d. Sugar dissolving in water e. Baking a cake 17. 8.35 x 10-6 mg = ______________________ kg (show all work using dimensional analysis). 18. How many ks are in 3,500 years? (show all work using dimensional analysis). 19. What type of mixture is a metal alloy? Justify your answer, then draw a diagram of what a metal alloy might look like at the atomic level. Be sure to label the parts.