CHEM 120 Week 3 Quiz

Institution	CHEM 120 Introduction to General, Organic, and Biological Chemistry with Lab
Contributor	Greenlee

Question: A reaction that releases energy as it is classified as an ____ while a reaction that absorbs

energy as it occurs is classified as an ____.

Question:Which coefficient is placed in front of potassium to balance the following equation? K+H2SO4-àK2SO4+H2= ____
Question: Which coefficient is placed in front of HCI to balance the following equation? Ca(OH)2 +? HCIàCaCl2 +H2O = ____
Question: Sodium reacts with oxygen to form sodium oxide and has the following chemical equation: 4 Na + O2 àNa2O. How many mole(s) of oxygen gas (O2) are needed to react with 8.0 moles of Na?
Question: Magneisum reacts with oxygen to form magnesium oxide and has the balanced chemical equation: 2Mg +O2 à 2 MgO. How many moles of MgO are produced when 5 moles O2 reacts completely?
Question: Determine number of atoms of the following molecule Na2CO3. Using periodic table determine the molar mass for this molecule:
Question: Determine number of atoms of the following molecule BaSO4. Using periodic table determine the molar mass for this molecule:

B=1

S=1

O=4

Molar Mass

(B) 1*137=137

(S) 1*32=32

(O) 4*16=64

Question: Calculate the concentration of NaCl (in water) solution in several ways and are given the following info: 25g NaCl, 500mL solution. Molecular weight of NaCl= 58.44 calculate mass/volume percent concentration and molarity of the solution
Question: What volume (L) of a 1.5 M KOH solution can be prepared by diluting0.2 L of a 5M KOH solution?

CV1= C2V2

C1=5

V1=0.2

C2=1.5

V2=?