Chapters 6-8 Review & Molarity Introduction Worksheet

Once completed, upload worksheet to the appropriate Assignments folder.

Write the correct chemical formula for the following combinations or compounds. You must have proper formatting to receive credit!

1. sodium and oxygen

2. Al and O

3. aluminum sulfide

4. potassium phosphide

Name the following compounds. Spelling counts!

5. KOH

6. O₂

7. NH₄C₂H₃O₂

8. PbCl₂

Solve the following conversions using the dimensional analysis format used in the previous worksheets.  Make sure to show all your work with units (an example has been provided) and label your answer with correct units.

Example: What is the molar mass of sodium chloride?  How many moles of sodium chloride are in 543 grams of sodium chloride?

Na=22.99 g/mol

Cl=35.45 g/mol

22.99g/mol + 35.45g/mol = 58.44 g/mol NaCl

Make sure you have amount, units, and material in all your work and every answer for full credit.

9. What is the molar mass of calcium chloride?  How many moles in 8.00 grams of calcium chloride?

10. What is the molar mass of water?  Convert 2.5 moles of water into grams.

Answer the following question.  You must have proper formatting to receive credit!

11. Write and balance an equation including correct states of matter for each of the reactant(s) and product(s) that represents the following reaction:  Although they were formerly called the inert gases, the heavier elements of Group 8 do form relatively stable compounds.  For example, at high temperatures in the presence of an appropriate catalyst, xenon gas will combine directly with fluorine gas to produce solid xenon tetrafluoride.

Molarity Introduction:  In future laboratory experiments, we will be measuring the amount of moles of solute found in a solution using the solution’s concentration.  The most common unit of concentration used by chemists is molarity.  The symbol used is a capital “M” and the units of molarity are moles of solute per liter of solution (moles/L).  Up until now, you have been given (or have measured) a mass of that substance and using the Periodic Table, have calculated moles.  Using the same dimensional analysis method, you can calculate moles of a solute given the concentration (molarity) of the solution.  Example:  How many moles of HCl are in 25 mL of a 8.0 M (this is read as “eight point zero molar “) solution of hydrochloric acid?

12. Calculate the number of moles of HF in 42.0 mL of a 3.16 M solution of HF.

13. How many moles of sodium hydroxide are in 80.0 mL of a 1.25 M solution of sodium hydroxide?

Identify the limiting reactant in the reaction of iron and chlorine to form FeCl₃, if 2.21×10¹ g of Fe and 3.59×10¹ g of Cl₂ are combined. Determine the amount (in grams) of excess reactant that remains after the reaction is complete.

Amount of excess reactant remaining =___________ g

An electrochemical cell, composed of an iron electrode (anode) immersed in 0.10 M Fe (NO3)2 and silver electrode (cathode) immersed in 0.11M AgNO3, was found to have a cell potential of 1.21V. The standard reduction potential for Ag+ / Ag half-cell is +0.80V. The standard reduction potential for the Fe+2/ Fe half – cell is -0.45V.

1. Write the half-cell reaction at the anode.

2.Write the half –cell reaction at the Cathode

3.Write over all cell reaction

4. Determine the standard cell potential using the standard reduction potential given above.

5. Determine the standard cell potential using the Nernst equation

Unknown A

Benedict’s Test: Bluish color

Seliwanoff’s Test: Red

Fermentation Test: Bubbles

Iodine Test: no color change

Unknown A is _______because_______________.

Unknown C

Benedict’s Test: Red-orange precipitate

Seliwanoff’s Test: no color change

Fermentation Test: Bubbles

Iodine Test: no color change

Unknown C is _______because_______________.

Unknown E

Benedict’s Test: Blue-green color

Seliwanoff’s Test: no color change

Fermentation Test: Bubbles

Iodine Test: Purple/Black color

Unknown E is _______because_______________.

Unknown G

Benedict’s Test: Yellow/orange precipitate

Seliwanoff’s Test: Red

Fermentation Test: Bubbles

Iodine Test: no color change

Unknown G is _______because_______________.

Unknown K

Benedict’s Test: Yellow/orange precipitate

Seliwanoff’s Test: no color change

Fermentation Test: No Bubbles

Iodine Test: no color change

Unknown K is _______because_______________.

Does either Ar or CO absorbs thermal IR?

which of the greenhouse gases absorbs thermal IR?

what are the two main anthropogenic sources of carbon dioxide in the atmosphere?

what are the two main sinks of atmospheric carbon dioxide?

If the cell potential for a voltaic cell is 0.250 V, and the reduction potential for the oxidation reaction is ⎯0.150 V, what is the reduction potential for the reaction occurring at the cathode?

The data below relate to the adsorption of N2 on rutile (TiO2) at 75 K. Confirm
that they fit a BET isotherm in the range of pressures reported, and determine Vmon
and c.

p/kPa 0.160 1.87 6.11 11.67 17.02 21.92 27.29
V/cm3 235 559 649 719 790 860 950

At 75 K, p* = 76.0 kPa. The volumes have been corrected to 1.00 atm and 273 K and
refer to 1.00 g of substrate

how do I know the intercept without graph excel in exam ?

1. You dissolve 5.00 g sodium hydrogen oxalate (NaHC2O4 ) in suffircient water to produce a final solution volume of 100.0 mL. Assuming all of the solid dissolves, calculate the pH of this solution.

2. You dissolve 5.00 g of sodium oxalate (Na2C2O4) in sufficient water to produce a final solution volume of 100.0 mL. Assuming all of the solid dissolves, calculate the solution pH of this solution.

3. You dissolve 5.00 g of sodium hydrogen oxalate and 5.00 g sodium oxalate in sufficient water to produce a final solution volume of 250.0 mL. Assuming both solids dissolve completely, calculate the pH of this solution.

4. Calculate the pH of the solution prepared in question #3 after 2.00 mL 1.00 M sodium hydroxide is added to it.

5. You dissolve 5.00 g sodium hydrogen oxalate and 1.00 g sodium hydroxide in sufficient water to produce a final solution volume of 250.0 mL. Assuming both solids dissolve completely, calculate the pH of this solution.

6. Calculate the pH of the solution prepared in question #5 after 2.00 mL 1.00 M hydrochloric acid is added to it.

Assume that at the start of the reaction ΔG is a large negative number. As the reaction proceeds toward equilibrium, which of the following are true?

1. The value of Q approaches the value of Keq.
2. The rate of the forward reaction is slowing down as the rate of the reverse reaction is speeding up.
3. The value of Q decreases.
4. The value of Keq decreases.
5. The value of Delta G° increases.
6. The value of Delta G° approaches the value of Delta G.
7. The value of Delta G increases.

Calculate the percent ionization of a 0.175 M hypobromous acid in pure water and in a 0.125 M potassium hypobromite solution. Explain (using a few sentences) why the percent ionization is different. The ionization constant for hypobromous acid is 2.8 x 10-9.

Calculate the pH at the equivalence point in titrating 0.047 M solutions of each of the following with 0.019 M NaOH.




(a) hydrochloric acid (HCl)

pH =  



(b) boric acid (H₃BO₃), K_a = 5.8e-10

pH =  



(c) arsenous acid (H₃AsO₃), K_a = 5.1e-10

pH =  

1. Carefully work through the sample calculations for this lab ON PAPER. Then, set up the same equations on a separate sheet of paper, but replace the values in the ‘Sample Calculations’ folder with the ones provided below and complete the calculations:

Mass of Zinc = 0.0928 g

H₂ volume reading from the eudiometer tube = 35.98 mL

Water bath temperature = 19.9 °C

Barometric pressure = 768.2 mm Hg

Level (pressure) difference from the meter stick = 41.20 cm H₂O (Pay attention to this unit!)

Note: to calculate the vapor pressure of water from the temperature given above, use the equation provided in Part 1 of the procedure.

b.) After completing your work on paper, record your answers below:

Vapor pressure of water =

Level difference in mm Hg =

H₂ partial pressure =

H₂ volume at STP =

H₂ moles =

H₂ molar volume at STP =

Before clicking on "Submit," verify that all your units are in place and that your significant figures / digits of precision are correct.

what is the rate determining step?

If you excite a fluorescent sample with light of 310 nm, in addition to the peaks from the light emitted by the molecule of interest, at what other wavelengths (in nm) would you expect to see peaks in the spectrum? Why?

The hydrolysis of the sugar sucrose to the sugars glucose and fructose, C12H22O11+H2O⟶C6H12O6+C6H12O6 follows a first-order rate law for the disappearance of sucrose: rate = k[C12H22O11] (The products of the reaction, glucose and fructose, have the same molecular formulas but differ in the arrangement of the atoms in their molecules.) (a) In neutral solution, k = 2.1 × 10−11 s−1 at 27 °C and 8.5 × 10−11 s−1 at 37 °C. Determine the activation energy, the frequency factor, and the rate constant for this equation at 47 °C (assuming the kinetics remain consistent with the Arrhenius equation at this temperature). (b) When a solution of sucrose with an initial concentration of 0.150 M reaches equilibrium, the concentration of sucrose is 1.65 × 10−7 M. How long will it take the solution to reach equilibrium at 27 °C in the absence of a catalyst? Because the concentration of sucrose at equilibrium is so low, assume that the reaction is irreversible. (c) Why does assuming that the reaction is irreversible simplify the calculation in part (b)?