Question

12. Write the appropriate nuclear symbol for each of the following isotopes: (a) Z = 11, A = 23 (b) Z = 28, A = 64 (c) Z = 50, A = 115 (d) Z = 20, A = 42

20. Ethane and acetylene are two gaseous hydrocarbons. Chemical analysis show that one sample of ethane contains 2.65 g of carbon and 0.668 g of hydrogen, and one sample of acetylene contains 4.56 g of carbon and 0.382 g of hydrogen. Write reasonable empirical formulas for these compounds. Ethane: Acetylene:

22. The atomic masses of 35Cl (75.53%) and 37Cl (24.47%) are 34.968 amu and 36.956 amu, respectively. Calculate the average atomic mass of chlorine. The percentages in parentheses denote the relative abundances ________ amu 26. Consider the combustion of carbon monoxide (CO) in oxygen gas: 2CO(g) + O2(g) → 2CO2(g) Starting with 3.09 moles of CO, calculate the number of moles of CO2 produced if there is enough oxygen gas to react with all the CO

27. The fertilizer ammonium sulfate, (NH4)2SO4, is prepared by the reaction between ammonia (NH3) and sulfuric acid 2NH3(g) + H2SO4(aq) → (NH4)2SO4(aq) How many kilograms of NH3 are needed to produce 3.60 × 105 kg of (NH4)2SO4? Enter your answer in scientific notation.

28. Identify each of the following as a combination, decomposition, or combustion reaction: C2H4O2(l) + 2O2 → 2CO2(g) + 2H2(l) 2Na(s) + Cl2(g) → 2NaCl(s) 2NaH(s) → 2Na(s) + H2(g)

35. (a) What is the Na+ concentration in each of the following solutions: 3.05 M sodium sulfate: M 1.98 M sodium carbonate: M 0.185 M sodium bicarbonate: M (b) What is the concentration of a lithium carbonate solution that is 0.795 M in Li+? 37.A sample of 0.7960 g of an unknown compound containing barium ions (Ba2+) is dissolved in water and treated with an excess of Na2SO4. If the mass of the BaSO4 precipitate formed is 0.8916 g, what is the percent by mass of Ba in the original unknown compound?

Answer 1