C 11) Calculate the following percentages. A) 30% of 300 B) 7.5% of 4.0 x 105 C) 0.50% of 0.060 12) Perform the following conversions within the metric system. A) 55 cm = B) 9535 m = C) 87 dg= D) 0.00376 L= B) 2.0 ft2= C) 19.8 qt= D) 78.2 lb = m km 8 13) Perform the following conversions. A) 56 cm = B) 254 K to C C) 947 K to F D) 84C to F E) 236F to K mL in cm2 L kg 14) Calculate the percentage by mass of the active ingredient in an antacid tablet that weighs 1.36 g if it contains 520 mg of calcium carbonate. 15) Convert the following temperatures to the indicated units: A) 549 F to C 11) 12) 13) 14) 15) Chem 104: Chapter 2 Practice Problems Name SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. 1) Write the symbolic notation (X) for the following information. A) 20 protons, 20 electrons, 20 neutrons B) 16 protons, 16 electrons, 16 neutrons C) 30 protons, 30 electrons, 35 neutrons D) 92 protons, 92 electrons, 146 neutrons 2) Complete the following table: Symbol 131 53 37 17 Atomic # 43 26 Mass # 99 56 #p 43 17 #n Date 20 #e 53 43 23 3) Write the symbol for the isotope of bismuth with 125 neutrons. 4) The element rubidium (Rb) comprises two naturally occurring isotopes with mass numbers 85 (atomic mass 84.91 amu) and 87 (atomic mass 86.91 amu). If the atomic mass of the element is 85.47 amu, deduce which isotope is more abundant. Calculate the isotope distribution of Rb. 5) The element magnesium (Mg) comprises three isotopes with mass numbers 24 (atomic mass 23.99 amu), 25 (atomic mass 24.99 amu) and 26 (atomic mass 25.98 amu), with the natural abundance of 78.99%, 10.00% and 11.01%, respectively. Calculate the atomic mass of Mg. 2) 3) 8) 10 1 6) Complete the following table. Emission Symbol 4 He 2 B) E) (beta neutron () D) F) 7) Complete the following equations with the symbol for the atom or particle represented by the blank space. Show the mass numbers and atomic numbers of the isotopes formed or the symbols of the subatomic particles: 206 p 210 A) 82 84 G) Po- 234 pa 91 233 UJ. 92 D 10 HH-He 1, 10 0 122 122, 53 54 325 - 1 16 236 U+He 92 0 -1 Xe. 133 56. 31 Charge 8) Write a nuclear equation for the following processes: A) Bismuth-214 undergoes beta decay. B) Thorium-230 decays to a radium isotope. C) Magnesium-23 undergoes positron emission. 9) What is the product of positron emission from F-187 10) You obtain a new sample of cobalt-60, half-life 5.25 years, with a mass of 400 mg. How much cobalt-60 remains after 15.75 years? 11) The units of activity are known as the curie (Ci) and the becquerel (Ba). Write down the relationship between them. 7) 9) 10) 11)