1. REVIEW : MOLE

2. 1. You have 7.57 g of each of the following elements: Si, S, Se, Sr, and Sn. Which sample contains the largest number of atoms? Si S Se Sr Sn Si

3. 2. If 1. 00 g of an unknown molecular compound contains 8
2. If 1.00 g of an unknown molecular compound contains 8.35 x 1021 molecules, what is its molar mass?
a) 44.0 g/mol
b) 66.4 g/mol
c) 72.1 g/mol
d) 98.1 g/mol
e) 132 g/mol
72.1 g/mol

4. 3. If 5.15 g Fe(NO3)3 is dissolved in enough water to make exactly mL of solution, what is the molar concentration of nitrate ion? Molar mass is g/mol M
b) M
c) M
d) M
e) M
0.426 M

5. 4.0 x10-2 x 1 mol CalCl2 x 1 Liter = 8.0 x 10-2 L
What volume of 0.25 M calcium chloride solution would contain 4.0 x 10-2 mol of chloride ions?
4.0 x10-2 x 1 mol CalCl2 x 1 Liter = 8.0 x 10-2 L
2 mol of Cl mol

6. 4. If mL of 4.50 M NaOH(aq) is diluted with water to a volume of mL, what is the molarity of the diluted NaOH(aq)? M
0.150 M
0.155 M
6.67 M
1.35 x 103 M
0.150 M

7. 5. Tin metal and purple iodine combine to form orange, solid tin iodide with an unknown formula, SnxIy.
Sn (s) + I2(s) --> SnxIy
Weighed quantities of Sn and I2 are combined, where the quantity of Sn is more than is needed to react with all of the iodine. After SnxIy has been formed, it is isolated by filtration. The mass of excess tin is also determined. The following data was collected:
Mass of Sn in original mixture = g
Mass of I2 in original mixture = g
Mass of tin in remaining = g
What is the formula of SnxIy?
SnI4

8. A student reacted grams of magnesium metal with atomic gaseous nitrogen, producing a residue having a mass of grams. What is the empirical formula of the ionic compound?
0.378 g g = g = mass of nitrogen
0.105 g / g/mol = mol N
0.273 g / 24.3 g/mol = mol Mg
/ = 1.50 : 1 = 3 : 2 => Mg3N2

9. You want to know the value of x in blue, hydrated copper (II) sulfate, CuSO4*XH2O. In the lab, you weigh out g of the solid. After heating the solid thoroughly in a porclein crucible, g of nearly white, anhydrous copper (II) sulfate remains. What is the formula and the name of the hydrate?
CuSO4x5H2O

10. 6. What is the percent of chlorine in (Z) 1,2- dichloro-3-hexene?
Draw the molecule before performing the calculation.
70.90 g/mol Cl
_____________ x100 = 46.32%
153.06g/mol