Chemistry Midterm Exam Review Sheet Spring 2012 1. Know your safety rules 2. A shopping mall wanted to determine whether the more expensive Tough Stuff floor wax was better than the cheaper Steel Seal floor wax at protecting its floor tiles against scratches. One liter of each brand of floor wax was applied to each of 5 test sections of the main hall of the mall. The test sections were all the same size and were covered with the same kind of tiles. Five (5) other test sections received no wax. After 3 weeks, the number of scratches in each of the test sections was counted. Identify the following components of an experiment. a. Problem: The Effect of the (changes in the independent variable) on the (dependent variable) write it using this format b. Hypothesis: If the (independent variable describe how it will be changed), then the (dependent variable describe the effect). -- write it using this format c. Independent variable - d. Dependent variable e. Control - f. Repeated trials g. Constants 3. State the law of conservation of mass. 4. Distinguish between the following word pairs (terms): a. homogeneous mixture and heterogeneous mixture b. element and compound 5. Identify the following as a heterogeneous mixture, compound, element, or homogeneous mixture: a. salt water b. gold c. water d. Italian dressing 6. Distinguish between a physical and a chemical change. 7. Identify the following changes as physical or chemical:
a. water freezing - b. paper burning - c. wax melting - d. metal rusting - 8. Identify the following properties as physical or chemical: a. density - b. flammability - c. reactivity d. temperature - 9. Distinguish between an endothermic and an exothermic reaction. 10. List the six phase changes and state if they are endothermic or exothermic. 11. How do intensive properties differ from extensive properties? 12. Label each of the following properties as intensive or extensive. a. mass b. density c. length d. melting point e. volume f. boiling point g. color 13. Compounds can be separated. Mixtures can be separated. List 3 separation techniques that can be used to separate mixtures and explain how they work. 1. How does qualitative data differ from quantitative data? Give an example of each. 2. What is the percent error equation? 3. A student measured a piece of steel pipe and found its length to be 5.4 m. The accepted length of the steel pipe is 5.1 m. Calculate the percent error. 4. Convert the following temperatures. a. 38 o C = K b. 543 K = o C c. 50 C is equal to Kelvin. 5. You report four measurements of mass, 7.52 g, 7.50 g, 7.51 g, 7.50 g. If the correct measurement is 7.85 g, are these measurements accurate? Are they precise? Explain your answer.
4. Describe how you add or subtract numbers using significant figures? 5. Describe how you multiply or divide numbers using significant figures? 6. Identify the number of significant figures in the following measurements: a. 1.00 g b. 0.0035 g c. 0.004500 g d. 101 g 7. Perform the following operations. Keep the correct number of significant figures. a. 4.56 cm x 9.1 cm = b. 20.0 4 = c. 7.1 + 6.00 = d. 8.0 4 = 8. List the appropriate SI unit for the following measurements. Define temperature and mass. a. Length b. mass c. volume d. temperature e. time f. quantity 9. Perform the following unit conversions: Use the factor label (dimensional analysis) method. a. 44 mm = km b. 15 lbs = mg (1lb = 454 g) c. 5.0 x 10 6 sec = days d. 14,110 ft = m (1m = 1.0936 yards) 10. How should all equipment be read? Read the following balance to the appropriate precision. 11. List the equipment that can be used to measure volume.
12. Read the following graduated cylinder to the appropriate precision. 13. Describe how you could determine the volume of an irregularly shaped object. 14. What is the formula for density? 15. What is the density of an unknown substance if the mass is 100g and the volume is 100 ml? 16. What is the volume of an object if its density is 1.0 g/cm 3 and the mass is 150 g? 17. What is the mass of an object if its density is 4.5 g/ml and the volume is 75 ml? 18. Given two substances, how do you know which one will float? 19. What type of physical property is density, intensive or extensive? What does that mean? 1. What is an atom? 2. List the 2 regions of an atom. What do they give to the atom? 3. List the 3 subatomic particles, their charges, their relative masses and their location in the atom. 4. Who discovered the nucleus in the famous gold foil experiment? What conclusions were drawn from this experiment?
5. Who proposed the first atomic theory in the 1800 s? What has been changed? 6. Who discovered the electron? 7. Which number identifies the element? 8. What is the mass number equal to? 9. How are the numbers of neutrons determined? 10. How are the numbers of electrons determined in a neutral atom? 11. How are the numbers of electrons determined in a cation? 12. How are the numbers of electrons determined in an anion? 13. Besides the atomic number, what other number is found on the periodic table. What is it and give its definition. 14. Define isotope. Given the following nuclide, explain all the numbers. the number of protons, neutrons and electrons and then do so. +3. Tell how you would find 15. Calculate the average atomic mass for element Z, if it has the following isotopes: Z-56 25% 55.98 amu Z-57 75% 56.99 amu 16. Define the following a. ion b. cation c. anion
17. Complete the following chart: Element Atomic # Mass # # Protons # Electrons # Neutrons Symbol (Nuclide) 6 14-1 Uranium-238 Magnesium-24 10 PERIODIC TABLE 1. The periodic table is divided into three main categories. Name them and give their location on the periodic table and their properties. 2. Mendeleev arranged the periodic table by increasing atomic. Moseley arranged the modern periodic table by increasing atomic. 3. Distinguish between groups and periods. 4. Which of the following elements have similar properties? Why? Ca, K, Kr, Cl, Br 5. Give the names of the following groups. a. Group 1 b. Group17 c. Group 2 d. Group 18 6. Where are the transition metals? Inner transition metals? 7. Which Group contains the most reactive metals? Reactive nonmetals?
8. Give the group and period for the following elements: a. helium b. bromine - c. calcium - d. copper 9. Identify the number of valence electrons present in the following elements: a. Radium b. Iodine c. Cesium d. Aluminum e. vanadium 10. Draw an electron dot structure for the following then predict the oxidation number or charge: a. Nitrogen b. argon c. magnesium d. sodium e. aluminum f. sulfur g. silicon h. fluorine 11. Which group of elements on the periodic table is most likely to donate one electron? UNIT 4 IONIC BONDING AND ACID NAMING 1. Which elements lose electrons? Gain electrons? Why? 2. Why do ions have a + or charge? 3. How many electrons are lost or gained if an ion has the following charge: a. +1 b. +2 c. +3 d. +4 e. 4 f. 3 g. 2 h. 1 4. What elements are Stable (lowest energy state)? 5. How many valence electrons are needed for an element to be considered stable? This known as the Rule. 6. Name the following ionic compounds: a. CaBr 2 e. SnBr 4 b. KF f. Na 2 CO 3 c. Mn(OH) 2 g. Cu 2 O
d. BeS h. PbCl 2 7. Write the formulas for the following ionic compounds. a. Sodium fluoride d. Iron (III) sulfate b. Calcium nitrate e. Sodium bicarbonate c. Magnesium nitride f. Lead (IV) Phosphate 8. List the rules for naming acids. 9. Write the formulas for the following acids. chloric acid phosphorous acid sulfuric acid 10. Name the following acids. HCl H 2 S HNO 2 11. Identify the properties of ionic compounds. 12. Draw the Lewis Structures for the following ionic compounds: sodium chloride, magnesium fluoride, Lithium oxide, Aluminum sulfide UNIT 5 CHEMICAL QUANTITIES 1. What is the value of Avogadro s number? 2. How many moles of chromate ions are in 5.50 moles of Pb(CrO 4 ) 2?
3. Work the following problems. a. Calculate the mass of 3.57 moles of aluminum. b. How many moles are in 25.0 g of Fe 2 O 3? c. Calculate the number atoms in 2.50 moles of Zinc. d. Determine the number of moles for 3.58 x 10 23 formula units ZnCl 2? e. Determine the number of molecules in 25.34 g of CO? f. Determine the mass in 6.11 x 10 25 atoms of sulfur? 4. Calculate molar mass for the following. a. AlBr 3 b. H 2 O 2 c. Mg 3 (PO 4 ) 2 5. Caffeine, a stimulant found in coffee, has the chemical formula C 8 H 10 N 4 O 2. Determine the percent composition of caffeine. 6. Compare molecular and empirical formulas. Be able to determine which compounds have the same empirical formula. 7. Determine the molecular formula for ibuprofen, a common headache remedy. Analysis of ibuprofen yields a molar mass of 206 g/mol and a percent composition of 75.7% C, 8.80% H an d15.5% O. (find the empirical formula first)
UNIT 6 CHEMICAL REACTIONS 1. List the 7 diatomic elements. 2. Define reactants and products and know where they are located. 3. List the types of reactions and how to identify them. 4. Know the symbols for all the states including aqueous and define aqueous. 5. Write and balance the following chemical equations, showing the states, and identify the type. Can be more than one. a. Solid calcium reacts with solid sulfur to produce solid calcium sulfide. b. Solid aluminum metal reacts with aqueous zinc chloride to produce solid zinc metal and aqueous aluminum chloride. c. Aqueous aluminum sulfate reacts with aqueous barium hydroxide to produce solid aluminum hydroxide and solid barium sulfate. d. Propane gas (C 3 H 8 ) reacts with oxygen gas to form carbon dioxide gas (CO 2 ) and water vapor. e. Solid silver oxide decomposes to produce solid silver and oxygen gas 2. Mixed Naming & Formula Practice:
Name Formula Formula Name copper (II) hydroxide FePO 4 silver chloride K 2 CO 3 hypochlorous acid HClO 3 iron (II) sulfate Cd(NO 3 ) 2 ammonium hydrogen sulfate Cs 2 C 2 O 4 iron (II) oxide Na 3 N ammonium sulfide SnI 4 magnesium phosphate HClO 3 nickel (II) bicarbonate SrSO 3 potassium dichromate HNO 2 phosphoric acid Ba(OH) 2 cobalt (III) nitrate H 3 PO 3 tin (IV) bromide H 2 S sodium hydrogen sulfate PbO silver chromate HNO 2