CP Chemistry Midterm Topic List Converting SI Units (Kilo, Hecto, Deca, Base Unit, Deci, Centi, Milli) Scientific Notation Precision versus Accuracy Properties of Matter Classification of Matter (Element/Compound/Mixture) Physical and Chemical Properties Physical and Chemical Changes (Evidence for ) Separations Density (Problems & Applications) Parts of an Atom Atomic Number, Atomic Mass, Mass Number Counting Protons, Electrons and Neutrons Ions and Isotopes Calculating Average Atomic Mass (Weighted Averages) The Periodic Table (Parts, Reactivity and other trends) Nuclear Equations including half-life Electromagnetic Spectrum Bright Line (Emission) Spectra Electron Configuration Ionic and Covalent Bonding (Lewis Dot Structures) VSEPR Theory (molecular shape including polarity) Naming Ionic Compounds Naming Covalent Compounds Writing a Chemical Reactions (symbols used in chemical reactions) Balancing Chemical Reactions Types of Chemical Reactions (synthesis, decomposition, combustion, single replacement & double replacement) Predicting Products of a chemical reaction Dimensional Analysis (Unit Factor Label Method) Avogadro s Number The Mole Converting from Grams <-> Mole <-> Atoms or molecules Gram Formula Mass (Molar Mass) Empirical Formulas Molecular Formulas Percent Composition Hydrates
Midterm Exam Review 1. Write the following in scientific notation:.005 5050 104.004 2. Write the following in standard notation: 1.5x10 3 3.75x10-2 2.15 X 10-4 3. What type of matter would you classify the following as: (element, compound, homogenous mixture, heterogenous mixture) Chlorine Water Rusty nail Kool-Aid Soil Alloy NaCl Silver 4. Classify the following as a chemical or a physical characteristic. Color Solubility Boiling point Density Hardness Flammability 5. Identify each of the following chemical or physical changes Burning coal Boiling water Drying clothes in dryer Milk souring Sawing wood Cooking an egg The amount of solid you were supposed to measure on a balance several times was 48.21g. Two groups try to measure 48.2g four times. These are their results: Group 1 Group 2 42.00g 47.34g 42.15g 49.12g 42.07g 48.21g 42.12g 50.55g 6. Which group is more accurate? 7. Which Group is more precise?
8. Complete the following table and identify the ion and the isotope. Sr +2 Atomic Mass = Atomic number = Mass Number = 18 O Sn Protons = Protons = Protons = Neutrons = Neutrons = Neutrons = Electrons = Electrons = Electrons = a. What is the difference between a nitrogen atom and an isotope of nitrogen? b. What is the difference between a nitrogen atom and an ion of nitrogen? c. What are the common oxidation states (charges) of the following: B H N O F 9. Practice Calculations a) SI prefixes are based on the number b) 0.15 km = m c) 24 L of water = ml of water d) 25.4 mg = mg e) 3.2m x 4.8m = f) 0.005 km/hr =? m/min g) 85 km/hr =? miles/day (1 mile = 1.609 km) h) 1 ml = cm 3 = cc
10. Density Calculate the following. Express you answer using correct units and significant figures. The formula for Density is. A unit of density is Is density an intensive or extensive property? Explain what your answer means. a. A plastic ball with a volume of 19.7 cm 3 has a mass of 15.8 g. Calculate the density of the plastic ball. b. If you place this ball in a container of water (density H 2 O = g/cm 3 ) will the ball float or sink? 11. Calculating Atomic Mass Neon has two isotopes. Using a weighted average of these isotopes, calculate the atomic mass for Neon. You must show all work to get credit. (4 pts) Neon 20 (90%) : mass = 19.992 amu Neon 22 (10%) : mass = 21.991 amu 12. Parts of an atom. Where is it found in atom? Proton Electron Neutron Definitions: Matter: Substance: Liquid: Solid: Gas: Charge
13. Formulas a. Find the empirical formulas for the following: Molecular Formula Empirical Formula H 2 O CH 3 COOH C 8 H 12 O 4 C 6 H 12 O 6 b. Find the empirical formula of a substance with a composition of 13.5 g Ca, 10.8 g O, and 0.675 g H. c. Find the empirical formula of a substance with a composition of 81.9% Ta and 18.1% O d. Find the molecular formula of CH 4 if molecular mass of the substance is 32g/mole? 14. Nomenclature a. Name the following compounds 1. FeBr 3 2. PCl 3 3. K 2 SO 3 4. P 2 S 5 5. Fe(NO 3 ) 2 6. XeF 4 7. CrS 3 8. PbSO 4
9. P 2 O 5 10. SCl 6 b. Name the following covalent compounds SF 2 Si 2 O 4 N 2 O 2 c. Name the following ionic compounds FeS NO 2 Pb(OH) 2 CdSO 4 Ca 3 N 2 Identify the following compounds as Ionic or Covalent and name 1) CO 2 2) CeO 2 3) PtO 2 4) Cl 2 5) CH 4 6) Bi 2 O 5 15. The Mole Calculate the following a. Calculate the molar mass for K 2 SO 4 b. What is the molar mass for CaSO 4 2H 2 O c. What is the mass in grams of 8.4 moles of the element tellurium, Te? c. 4.4 X 10 25 atoms of Fe is how many grams?
d. 26 grams of Fe 2 O 3 has how many atoms of Fe 2 O 3? e. How many moles of KNO 3 is in 20.0g? f. How many moles of water are found in 125 g of CaSO 4 2H 2 O 16. Percent Composition/Hydrates a) What is the percent by mass of hydrogen in aspirin, C 9 H 8 O 4? b) A hydrate is a compound that includes water molecules within its crystal structure. During an experiment to determine the percent by mass of water in a hydrated crystal, a student found the mass of the hydrated crystal to be 4.10 grams. After heating to constant mass, the mass was 3.70 grams. What is the percent by mass of water in this crystal?
c) In which compound is the percent by mass of oxygen greatest? (1) BeO (2) MgO (3) CaO (4) SrO d) A 2.500 gram sample of a hydrate of calcium sulfate loses 0.523 grams of water when heated. Determine the formula of the hydrate. 17. Chemical Reactions Identify the following chemical equations by type. a. C 4 H 8 + 6O 2 ---> 4CO 2 + 4H 2 O b. HCl + NaOH ---> H 2 O + NaCl c. 2KNO 3(s) ---> 2KNO 2 + O 2 d. AgNO 3 + NaCl ---> NaNO 3 + AgCl e. 2Mg + O 2 ---> 2MgO f. 2Ag + S ---> Ag 2 S g. MgCO 3(s) ---> MgO + CO 2 h. Cl 2 + 2KBr ---> 2KCl + Br 2 Balance the following equations: i. Fe + O 2 Fe 2 O 3 j. Al(NO 3 ) 3 + H 2 SO 4 Al 2 (SO 4 ) 3 + HNO 3 k. PbO 2 PbO + O 2 Predict the Products of the following reactants and write a balanced equation for it. l) Iron metal and copper (II) chloride
m) Zinc metal and oxygen gas make zinc oxide n) Magnesium Chloride and Silver Nitrate o) Iodine gas reacts with Sodium chloride p) The combustion of propane q) Potassium sulfate reacts with Calcium nitrate r) Aluminum metal reacts with Iron (II) nitrate 18. Electromagnetic Spectrum: Label (place in order) gamma rays, microwaves, radio waves, ultraviolet rays, infrared rays, and visible light on the electromagnetic spectrum below:
Energy 19. Complete the following nuclear equations, and indicate the type of emission (alpha or beta -) Emission a) 238 92 U 234 90 Th + b) 234 234 90 Th 91 Pa + 20. How much time is required for 5.80 mg of 51 Cr to decay to 1.45 mg if it has a halflife of 27.8 days? 21. Write out the full (longhand) electron configuration for: a) 14 Si b) 28 Ni c) 63 Eu 22. Write out the condensed (shorthand) electron configuration: a) 34 Se b) 58 Ce c) 75 Re
23. Given the elements Al, Cs, F, Fe, N. List them in order of: a) atomic radius from smallest to largest b) first ionization energy from lowest to highest c) electronegativity from lowest to highest 24. Given the elements B, Cl, Li, Ne, Ra, S, W a) Which is an alkali metal? b) Which is a halogen? c) Which is a chalcogen? d) Which is a transitional metal? e) Which is a metalloid? f) Which has a complete octet in its valence? 25. Complete the chart below Molecule Lewis Structure Molecular Geometry Molecular Polarity CH 2 Cl 2 HCN
PCl3