21) The rate of reaction depends upon: a. the concentration and nature of reactants b. the temperature of the reaction C. whether or not a catalyst was used d. all of the above 22) A Maxwell-Boltzmann curve shows the distribution of molecular energies in a reaction system. When the temperature in this system is increased, the peak is a. higher and further to the right. b. higher and further to the left. c. lower and further to the right. d. lower and further to the left. 23) Which of the following correctly describes the reaction represented by the reaction below? CaCO3 (s) + energy → CaO (s) + CO2 (g) a. It is exothermic and the potential energy is greater in the reactants than the products. b. c. It is exothermic and the potential energy is greater in the products than the reactants. It is endothermic and the potential energy is greater in the products than the reactants. d. It is endothermic and the potential energy is equal for the products and reactants.

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27) Draw the energy level diagram and write the full and shorthand electron configuration for a neutral sulfur atom.

Indicate whether these compounds are isomers, enantiomers, or tautomers. OCH OCH محمد ممد

30) Substance A to E below are listed with several of their properties. The identities of the substances are identified in random order below: Iron, ethane, ethanol, sodium nitrate, graphite First classify each substance as either a polar covalent compound, non-polar covalent compound, ionic compound, metallic solid, or network solid. Write your predictions in the sixth coloumn of the chart, under "type of substance." Then, identify the identity of the substance in the last coloumn. Substance Melting Point Boiling Point Solubility in H₂O Electrical Conductivity Type of Substance Identity of Substance (°C) (°C) as: Solid, Liquids, Solution A -182 -88 Insoluble No/No/- B 1538 2862 Insoluble Yes/Yes/- C 308 380 Soluble Yes/Yes/Yes Ꭰ 3456 Insoluble No/-/- E -114 78 Soluble No/No/No

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28) Explain the process of galvanization. In your description, make sure to explain what metal is usually used for galvanization and why this metal used.

29) Complete the following table Molecule H₂O NH3 Lewis Dot Diagram VSEPR Diagram Name of VSEPR Shape

12) What is the best name to describe the shape of water molecule? a. Angular b. C. Tetrahedral Octahedral d. Trigonal pyramidal 13) Network solids are distinguished from metallic crystals in that: a. Network solids have charged ions, while metallic crystals do not. b. Network solids are composed of molecules, while metallic crystals only have one type of atom. C. Network solids are composed of non-metals. d. Network solids have much lower boiling points.