1.Indicate whether each of the following is true or false: A. For the main group elements the number of valence electrons is the group number. B. An element has an electron configuration of 1s22s22p63s2Its +2 ion has a configuration of 1s22s22p6 C. A covalent bond between H and F is less polar than a covalent bond between H and C D..There are no exceptions to the octet rule. E. Resonance is said to occur when electrons transfer from one atom to another.. F. In transition elements the electron configurations involve filling d orbitals. G. A set of 2p orbitals has a maximum capacity of 2 electrons. H By the Bohr theory energy is emitted when an electron in a H atom moves from an orbit with a higher n value to an orbit with a lower n value. I. A 3s orbital is larger than a 2s orbital. J. For electromagnetic energy as wavelength increases, frequency increases.. 2. How is the percent yield of a reaction determined ? 3. Considering the reaction: 4Al(s) + 3O2(g)→ 2Al2O3(s) A. How many moles of O2are needed to react with 3.55 moles of Al? B. How many grams of Al2O3result when 175 g of Al react ? 4. Step 2 in determining the Lewis Structure of a covalent species says to” sum the valence electrons for each atom, and if the species is a polyatomic ion, subtract electrons for positive ions and add electrons for negative ions. This gives the total electrons for the Lewis structure.” Determine the total electrons for the following : A. H2S B. PBr3C. SO3 D. CCl4 E. CO32- 5. When CuCl2(aq) is added to AgNO3(aq) a precipitate forms. Write the complete balanced equation for this reaction. 6. Balance the following equations: A. N2+ H2→ NH3 B. Ca3N2+ H2O → Ca(OH)2+ NH3 C. C4H10+ O2→ CO2+ H2O D. H3PO4+ KOH → K3PO4+ H2O E. PCl3+ H2O → H3PO4+ HCl 7. A solution consists of 15.0g of NaOH in 125g of water A. What is the % of NaOH in the solution ? B. What is the molality of the solution ? 8. Considering the following 1.0 molal solutions: 1.0m sucrose 1.0m KCl 1.0m AlCl3 1.0m CaCl2 1.0m Ca(NO3)2 Which one has the lowest freezing temperature and why ? 9. How many milliliters of a 2.00molar solution of NaOH in water are needed to Provide 25.0grams of NaOH ? 10. How many joules of energy are needed to increase the temperature of 201.0grams Of water from 25.0 degrees C to 95.0 degrees C ? The specific heat of water is 4.184 J/g-degree |