Arsenic is a toxic metal that can be found in the water supply. Begin a discussion on arsenic in water by answering the following questions: What are the current federal standards for arsenic in drinking water? Is this standard the same for arsenic in drinking water in Europe? How does arsenic in water affect the body? What are some side effects?

1. Write the net ionic equation for the reaction that occurs when equal volumes of 0.256 M aqueous hypochlorous acid and sodium fluoride are mixed (there should be 2 spots before and after arrows)

at equilibrium is it product or react favored

and is the ph <, =, or > than 7?

2. Write the balanced NET IONIC equation for the reaction that occurs when hydrochloric acid and potassium cyanide are combined. (there should be 2 spots on both sides of arrows)

Also, is the reaction classified as: strong acid + strong base, weak acid + strong base, strong acid + weak base, or weak acid + weak base?

The extent of this reaction is: below 50, 50, above 50, or 100%?

3. Write the balanced net ionic equation for he reaction that occurs when acetic acid and barium hydroxide are combined. (2 on the left and 3 spots on the right of arrows)

Also, is the reaction classified as: strong acid + strong base, weak acid + strong base, strong acid + weak base, or weak acid + weak base?

The extent of this reaction is: below 50, 50, above 50, or 100%?

Would the molecules PO₃^3-, NO₂F, and BrF₃ bond to Rh+ and what atom would serve as the donor atom? Which would be the most favorable and why?

Element: LEAD

Expectations include but not limited to physical properties (color, density, refractive index, boiling point, melting point, crystal or amorphous, etc), absorption wavelength, chemical properties, density, refractive index (if exist)most common compounds it makes, availability in nature and in daily products we use, any significance forensic science.

Tetramethylsilane (TMS) is the accepted internal standard for calibrating chemical shift ppm values for 1H, 13C, and 29Si NMR spectroscopy in organic solvents.

In 1H-NMR, the TMS peak is assigned 0 ppm. This is upfield of most proton peaks observed for organic compounds. Briefly explain why the protons in TMS appear at this upfield location in a 1H-NMR spectrum.

Considering the range of hertz values possible for a spectrometer, why is the ppm scale used? To what does the ppm scale refer?

How many molecules of ATP are produced for each unit of GTP formed in the citric acid cycle?

A solution contains Al 3 + and Co 2 + . The addition of 0.3488 L of 1.779 M NaOH results in the complete precipitation of the ions as Al ( OH ) 3 and Co ( OH ) 2 . The total mass of the precipitate is 22.32 g . Find the masses of Al 3 + and Co 2 + in the solution.

Answer these 2 questions

1. Predict how a buffer of HA and A- will resist change in pH when a strong acid is added. Write down a reaction to represent your prediction.

2. Acetic acid is CH3COOH, the Ka for acetic acid is 1.8x10-5.  

   1. Write the dissociation reaction for acetic acid.

   2. Calculate the pH of a 0.240 M acetic acid solution.

   3. Why would sodium acetate need to be added to acetic acid to create a buffer?

   4. Once the buffer of acetic acid and sodium acetate is made write a reaction showing how the buffer resist a change in pH when HCl(aq) is added.

   5. Once the buffer of acetic acid and sodium acetate is made write a reaction showing how the buffer resist a change in pH when NaOH(aq) is added.

Using the appropriate K_sp values, find the concentration of Cu²⁺ ions in the solution at equilibrium after 650 mL of 0.45 M aqueous Cu(NO₃)₂ solution has been mixed with 500 mL of 0.25 M aqueous KOH solution. (Enter in M.) (K_sp for Cu(OH)₂ is 2.6x10^-19).AND find the concentration of OH^? ions in this solution at equilibrium. (Enter in M.)

(1)    Think of (or find) a medication you have taken or otherwise know about. Research that medication and report the following:

a.    Trade Name and picture of medication

b.    Generic Name

c.    CAS Number

d.    What is it used for?

e.    Upload the structure of the molecule to the Resources area in your Workspace and embed it in your post by linking to it. Or, you can directly link to it on the web if the picture is on its own webpage.

f.     Identify the common functional groups on your molecule (see Table 18.7 in the text).

g.    On what part of the body, system in the body or receptors in the body does this medication act on?

h.    If your medication

The energy density of starlight in interstellar space is 10–15 J/m3. If the average wavelength of starlight is 500 nm, what is the corresponding density of photons per cubic meter of space? (photons/m3)

For each of the following solutions, calculate the initial pH and the final pH after adding 0.010 mol of NaOH.

PART A: For 240.0 mL of pure water, calculate the initial pH and the final pHpH after adding 0.010 mol of NaOH (pH initial,pH final)

PART B: For 240.0 mL of a buffer solution that is 0.200 MM in HCHO2 and 0.275 MM in KCHO2 calculate the initial pH and the final pHpH after adding 0.010 mol of NaOH(pH initial,pH final)

PART C: For 240.0 m of a buffer solution that is 0.305 MM in CH3CH2NH2 and 0.275 MM in CH3CH2NH3Cl, calculate the initial pH and the final pHpH after adding 0.010 mol of NaOH.(pH initial,pH final)

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