University:
Arizona State University
Course:
CHM 101 | Introductory Chemistry
Academic year:

2019
Views:

89

Pages:

4
Author:

5prinzg1s

1. Question: (TCO 7) (a, 5 pts) Given that the molar mass of HPO is 97.994 grams, determine the number of grams of H.PO needed to prepare 0.25L of a 0.2M H₃PO₄ solution. Show your work. (b, 5 pts) What volume, in Liters, of a 0.2 M H₂PO solution can be prepared by diluting 50 mL of a 5M HPO solution? Show your work. (Pts. 10) A. Molarity moles of solute/iters of solution moles of solute 0.2 M 0.25 L = 0.05 mol HH3PO4 Using the molar mass given, convert this amount to grams mass 0.05 mol (97.994 g/mol) = 4.89 grams H3PO4 B. C1V1 C2V2. C * 1 = 51 VL = 0.05L C * 2 = 0.2M VZ = [(5M)(0.05L)] / (0.2M] = 1.25L 2. Question: (TCO 7) (a, 5 pts) What is the mass/volume percent of a solution prepared by dissolving 43 g of NaOH in enough water to make a final volume of 120 mL? Show your work. (b, 5 pts) How many mL of a 10% solution can be made from the solution in part a? Show your work. 2. First convert the given mass of NaOH to volume (in mL) using the density of NaOH which is 2.13 g/ml. Volume43 g (1 ml/2.13 vartheta = 20.19mL Volume % (volume of solute/volume of solution) 100% Volume % (20.19 mL/120 mL) 100% = 16.8% b. Volume % volume of NaOH/ total volume 0.1020.19 mL/total volume Solving for total volume yields: V total201.88 11 So, about 202 mL of a 10% sokition can be made from the solution in part a. 3. Question: (TCO 12) Polyethylene is a polymer found in many applications, including packaging for fruit and vegetables. Discuss the structural differences between (1) polyethylene, (2) polypropylene, and (3) polystyrene and how the structure impacts their commercial uses. (Pts: 15) 1. The prevalent plastic polyethylene is the simplest and least expensive synthetic polymer. It is familiar today in the plastic bags used for packaging fruit and vegetables, in garment bags for dry-cleaned clothing, in garbage-can liners, and in many other items. Polyethylene is made from ethylene (CH2=CH2) an unsaturated hydrocarbon (Chapter 9) produced in large quantities from the cracking of petroleum, a process by which large hydrocarbon molecules are broken down into simpler hydrocarbons, 2. Polypropylene is a tough plastic material that resists moisture, oils, and solvents. is molded into hard-shell luggage, battery cases, and various kinds of appliance parts. It is also used to make packaging material, fibers for textiles such as upholstery fabrics and carpets, and ropes that float. Because of its high melting point (121 °C), polypropylene objects can be steriäzed with steam 4. Question: (TCO 11) Tungsten (W), with a mass number of 180 and an atomic number of 74, decays by emission of an alpha particle. Identify the product of the nuclear reaction by providing its atomic symbol (5 pts), mass number (5 pts), and atomic number (5 pts). (Pts. 15) mass of 180 becomes 176 atomic number of 74 becomes 72 name: Hafnium Symbol: H 6. Question: (TCO 13) What is the mRNA sequence for the following segment of DNA: --TAACGAATAGCCTGT-- (10 pts)? Based upon the mRNA sequence, what is the peptide sequence (10 pts)?