CHEM 120 WEEK 3 QUIZ UPDATED 2021

Question : (TCO 5) What coefficient is placed in front of O2 to complete the balancing of the following equation? C5H8 ? O2 – 5 CO2 4 H2O Question : (TCO 5) Magnesium reacts with oxygen to form magnesium oxide and has the following balanced chemical equation: 2 Mg O2 – 2 MgO. How many mole( s) of oxygen gas (O2) are needed to react with 4.0 moles of Mg? Question : (TCO 5) Determine the # of atoms for each element present in the following molecule: Mg(OH)2 (3 pts.). Using the periodic table of elements, determine the molar mass for this molecule (7 pts.). Question : (TCO 7) You are asked to calculate the concentration of a KCl (in water) solution in several ways and are given the following information: 3.5 g KCl, 50 mL solution, 50 g water, 1 mole KCl = 74.6 g KCl. (1) Calculate the mass/volume percent concentration (4 pts.). (2) Calculate the Molarity of the solution (6 pts.).