Question

Instructions: You have until the end of the period to finish the quiz. You may use a calculator but not a cell phone-based calculator. All calculated answers must be shown to the correct number of significant digits, have work shown, and have the correct units, failure to do so will result in a penalty. When you are finished please bring your quiz to the front of the class and quietly leave. 1. Fill in the missing information for the following table of isotopes of neutral atoms. (1 pt each) Element Name / Atomic Symbol Barium #of Protons #of Neutrons 81 Iron 137 Ba 57Fe - 26 Aluminum 13 128 Te 52 T 2. Convert 25849000 mL into KL, with the correct number of significant figures. (3 pts) 3. An unknown element has three main isotopes with the following masses and abundancies: 35.9675 amu 0.33653%, 37.962 amu 0.063250%, and 39.962 amu 99.600%. What is the element's atomic weight? (2 pts)

Answer 1

The solution is given in the following image:

Bacum : # number of pocofon + 56 Yoon : # of Neutron's + 3/ Aluminium : Atomies Symbol - Al Teluruum: 128 Te = 25.849000 KL 3) 25899000 mL 25849000 mL = = 35849.000L To get the atomic weight we have to we multiply the abundance to with the masses of the isotopes i.e. Atomic weight = (3065° x 35-9675) + (0-063250% 37.962 +(97.600x39.962) 100 = 0.12104 + 0.024011 + 39.802 = 39.997 (Answer)