Chemistry Exam 1 - October 2006 - Prof. P. Van Koppen, Exams of Chemistry

Download Chemistry Exam 1 - October 2006 - Prof. P. Van Koppen and more Exams Chemistry in PDF only on Docsity! Chem. 1A Exam 1 White Version October 23, 2006 1 1. (4 pts) Write the appropriate symbol for the species containing 16 neutrons, 16 protons, and 18 electrons. 2. (6 pts) Write the molecular formula for the following compounds: lead (II) phosphate ammonium hydroxide 3. (6 pts) The mass of the compound X3(PO4)2 is 310.18 g/mol. Identify X in this compound. 4. (12 pts) Circle true or false for each of the following statements about atomic structure. a) The electrons occupy a very large volume compared to the nucleus. True False b) Almost all of the mass of the atom is concentrated in the nucleus. True False c) The number of protons and neutrons is always the same in a neutral atom. True False d) The protons and neutrons in the nucleus are very tightly packed. True False e) A cation is formed when an atom gains electrons. True False f) The number of protons is the same for all neutral atoms of an element. True False 5. (6 pts) Balance the following equation using integer coefficients. FeS2 + O2 Fe2O3 + SO2 6. Aqueous calcium nitrate reacts with aqueous ammonium carbonate to produce a precipitate. Chem. 1A Exam 1 White Version October 23, 2006 2 a) (6 pts) Write the balanced molecular equation for the reaction using integer coefficients. b) (3 pts) Write the molecular formula for the precipitate that is formed in this reaction. c) (4 pts) Write the balanced net ionic equation for the reaction using integer coefficients. 7. (10 pts) Calculate the chloride ion concentration (in mol/L) when 40.0 mL of 3.0 M calcium chloride is added to 50.0 mL of 4.0 M sodium chloride.