Chem120 Week 3 Quiz 2020

Question 1 :       (TCO 5) In the following reaction, HCl is __________ ; and NaCl is ___________.

NaOH + HCl à NaCl + H2O

                                         Catalyst; reactant

                                         Product; reactant

                                         reactant; catalyst

                                         reactant; product

Question 2.                     (TCO 5) Which coefficient is placed in front of H2O to balance the following equation? Ca(OH)2 + HCl ---> CaCl2 + ? H2O

                                         1

                                         2

                                         3

                                         4

                                         5

Question 3.                     (TCO 5) Which coefficient is placed in front of CaO to balance the following equation?

CaCO3 à ? CaO + CO2

                                        1

                                         2

                                         3

                                         4

                                         5

Question 4.                     (TCO 5) Sodium reacts with oxygen to form sodium oxide and has the following balanced chemical equation: 4 Na + O2 --> 2 Na2O.

How many mole(s) of oxygen gas (O2) are needed to react with 2.0 moles of Na?

                                        0.5 moles

                                         3.0 moles

                                         1.0 moles

                                         2.0 mole

                                         4.0 moles

Question 5.                     (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 MgO are produced when 4 mole O2 reacts completely?

                                         2 mole

                                         4 mole

                                         10 mole

                                         8 mole

                                         1 mole

Question 6.                     (TCO 5) (a) Determine the number of atoms for each element present in the following molecule: Cu(CN)2 (2 points).

(b) Using the periodic table of elements, determine the molar mass for this molecule (3 points). Show your work.

Question 7.                     (TCO 5) (a) Determine the number of atoms for each element present in the following molecule: Mg(NO3)2 (2 points).

(b) Using the periodic table of elements, determine the molar mass for this molecule (3 points). Show your work.

Question 8.                     (TCO 7) You are asked to calculate the concentration of a NaCl (in water) solution in several ways and are given the following information: 30 g NaCl, 300 mL solution, Molecular weight of NaCl = 58.44 g/mole. Students must show ALL work for parts a and b.

(a) Calculate the mass/volume percent concentration (4 points).

(b) Calculate the molarity of the solution (6 points).

Question 9.                     (TCO 7) What volume (L) of a 0.5 M KOH solution can be prepared by diluting 1.5 L of a 10 M KOH solution? Show your work.