16: Problem-Solving and Discussion Worksheets

Measurements Matter

1. Express the following values in scientific notation.
   1. 150,000,000
   2. 0.000043
   3. 332000
   4. 0.0293
   5. 932
   6. 0.1873
   7. 78,000
   8. 0.0001
   9. 4500
   10. 0.00290
   11. 6281
   12. 0.00700
2. Express the following values in decimal notation.
   1. 3.8 x 10-3
   2. 9.21 x 105
   3. 7.91 x 10-2
   4. 2.5 x 106
   5. 3.42 x 10-8
   6. 5.4 x 105
   7. 3 x 10-3
   8. 7.34 x 102
   9. 9.8 x 10-4
   10. 6 x 107
   11. 4.20 x 10-6
   12. 4.20 x 106
3. What SI base unit would be appropriate for each measurement?
   1. the length of a room
   2. the amount of carbon in a diamond
   3. the mass of NaCl in a bottle
4. List the meaning of each abbreviation of the base units.
   1. m
   2. K
   3. kg
   4. s
   5. mol
5. Give the meaning and name of each metrix prefix abbreviation.
   1. M
   2. m
   3. n
   4. d
6. Convert each temperature to the missing one between Celsius and Fahrenheit.
   1. 77°F
   2. 212°F
   3. 37°C
   4. 22°C
   5. 95°F
   6. 15°C
   7. 0°F 
   8. 0°C
   9. –10°C
   10. –10°F

Significant Figures

1. 1. Explain the similarities and differences between accuracy and precision.
2. Determine the number of significant figures in each of the following values.
   1. 406
   2. 3.00
   3. 3.20
   4. 0.25
   5. 0.0689
3. Write each value with three significant figures, use scientific notation if necessary.
   1. 34500
   2. 24
   3. 0.0345
   4. 0.012
   5. 612.8
4. Find the result of each of the following calculations and report the value with the correct number of significant figures.
   1. 0.23 + 12.2 =
   2. 13 - 1.03 =
   3. 0.839 + 0.28925 =
   4. 28 + 34.4 =
   5. 0.8 + 2.3 =
   6. 34.9 - 0.583 =
5. Find the result of each of the following calculations and report the value with the correct number of significant figures.
   1. 34 x 0.12 =
   2. 68.2 / 0.78 =
   3. 3.29 x 104 x 16.2 =
   4. 0.8449 x 29.7 =
   5. 5.92 x 103 / 0.628 =
   6. 3.00 x 2.6 =

Scientific Dimensional Analysis

1. Complete each of the following conversions.
   1. 34 cm to m
   2. 3.7 ft to in
   3. 345 mg to Mg
   4. 5.3 km to mm
   5. 4.0 L to mL
   6. 3.45 x 103 mm to km
   7. 78 cm3 to mL
   8. 0.85 kg to dg
   9. 13 pints to gallon 
   10. 0.35 L to cm3

Percentages

1. Solve each of the following.
   1. What percent of 35 is 8.2?
   2. What percent of 56 is 12?
   3. What percent of 923 is 38?
   4. What percent of 342 is 118?
2. Solve each of the following?
   1. What is 42% of 94?
   2. What is 83% of 239?
   3. What is 16% of 45?
   4. What is 38% of 872?
3. A patient originally weighs 182 pounds and loses 15.0% of their body weight. What is their final weight?
4. A patient's original weight was 135 pounds and they lose 12 pounds. What percent of their body weight did they lose?
5. A patient needs to increase their calcium supplement by 25% a week. If they are currently taking a 300. mg supplement, how much more will they need to take?
6. A patient needs a 20.0% decrease in their medication dosage from 125 mg. What will his dosage be after the decrease?

Elements and Atomic Structure

1. Using the periodic table, identify the atomic symbols and names of the elements that correspond to the following atomic numbers:
   1. 8
   2. 27
   3. 33
   4. 59
   5. 90
2. How many electrons do each of the following elements contain? Hint: These are not ions, but neutral elements.
   1. Fluorine
   2. Magnesium
   3. Iodine
   4. Copper
   5. Silicon
3. Which elements contain the following numbers of protons and electrons?
   1. 15 protons and 15 electrons
   2. 77 protons and 77 electrons
   3. 42 protons and 42 electrons
   4. 4 protons and 4 electrons
   5. 99 protons and 99 electrons
4. What is an isotope? How does one isotope differ from another within the same element?

Periodic Table of Elements

1. One of the main groups on the periodic tables is the Metals. How many different subgroups of metals are there on the periodic table? Name each of them. Where in the periodic table can each subgroup be located? Be specific.
2. Determine if the following descriptions are examples of a physical or chemical property.
   1. Iron nails rust when left out in the rain
   2. Glass is transparent and rigid
   3. Table salt creates an electrical current when dissolved in water
   4. Diamond is virtually unbreakable 
   5. Metallic sodium explodes when exposed to water
3. Of the following elements, which of the three categories, metal, non-metal and metalloid, do they each belong to?
   1. Manganese
   2. Bromine
   3. Silicon
   4. Uranium
   5. Phosphorus
4. For periods 1-6, how many electrons are in each energy level? How many valence electrons do the following elements from levels 2 and 3 have?
   1. Fluorine
   2. Aluminum
   3. Nitrogen
   4. Magnesium
   5. Silicon

Half-Life

1. The half-life for Tc-99m is 6 hours. A 100-gram sample of technetium-99 is stored for 30 hours. How much of the radioisotope is left after that time period? How many half-lives have elapsed after the 30 hours?
2. The half-life for Kr-79 is 34.5 hours. How long would it take for 50 grams of Krypton79 to decay to 6.25 grams? What percentage of the initial 50 grams does the 6.25 grams represent? How many half-lives did it take to decay down to 6.25 grams?
3. If 64 grams of fluorine-18 is administered to a patient, how much will be left after 4 half-lives? If the doctor expects the patient to have less than 5% of it left in their system, how many half-lives will that take?

Compounds Containing Polyatomic Ions

1. Translate the formula of each polyatomic ion into its name.
   1. O2 2-
   2. SO4 2-
   3. CO3 2-
   4. OHe. ClO
2. Give the names of each polyatomic ion in the following groups.
   1. HCO3 - , CH3CO2 -
   2. SO3 2-, SO4 2-
   3. CN- , OHd. NO2 - , NO3 -
   4. PO4 -3, HPO4 -2, H2PO4 -1
3. Use the names of the given polyatomic ion names to write their formulas. Include the charge of each ion.
   1. ammonium ion
   2. bicarbonate ion
   3. hypochlorite ion
   4. bisulfate ion
4. For each set of polyatomic ions named here, give the formulas for each.
   1. Hypochlorite and chloride
   2. Phosphate and biphosphate
   3. Carbonate and bicarbonate
   4. Sulfate and bisulfate
   5. Hydroxide and hydride
5. Provide the formula for each ionic compound named below.
   1. Sodium hypochlorite
   2. Potassium hydroxide
   3. Ammonium nitrate
   4. Aluminum sulfate
   5. Iron(III) cyanide

Writing Formula Units and Naming Compounds

1. Provide the name of the individual ions that make up each of the following ionic compounds and indicate how many of each ion there are.
   1. Al(OH)3
   2. Li3PO4
   3. KCl
   4. ZnF2
   5. Na2O
2. Combine the following pairs of elements (or ions) to express them as an ionic compound.
   1. Sodium and Sulfur
   2. Barium and Iodine
   3. Iron(III) and Oxygen
   4. Aluminum and Bromine
   5. Lithium and Nitrogen
3. Provide the name of each ionic compound below.
   1. Ag2O
   2. ZnCl2
   3. Au(NO3)3
   4. KOH
   5. BaBr2
4. Name each ionic compound AND give the names of the individual ions that make up the formula.
   1. Hg2S
   2. Cr2O3
   3. K2SO4
   4. Fe2(CO3)3
   5. Zn(ClO)2
5. Determine whether each compound is ionic or covalent
   1. P2O5
   2. MgCl2
   3. NaC2H3O2
   4. NH3 
   5. CCl4
6. Transition metals tend to have varying charges. Determine the charges on each transition metal in the following ionic compounds.
   1. AuN
   2. SnO2
   3. Cu2S
   4. PbBr4
   5. FeI2

Molecular Mass, Formula Mass, and Molar Mass

1. What value is held by Avogadro’s number?
2. What is the mass of each of the following quantities:
   1. 1.0 mole of Hydrogen gas
   2. 2.0 moles of water
   3. 0.1 moles of lead
   4. 0.50 mole of hydrochloric acid (HCl)
   5. 3.0 moles of Helium
3. What is the atomic mass of CH3OH, ethanol, in AMU? What is the molar mass?
4. For each of these different compounds, using the given masses, calculate how many moles each sample contains.
   1. In 3.1 grams of sodium chloride
   2. In 4.8 grams of hydrogen peroxide
   3. In 8 grams of lithium hydroxide
   4. In 10. grams of oxygen gas
   5. In 22 grams of ammonia
5. Contrasting with the previous problem, this time find the mass of each sample by using the given number of moles.
   1. 6.0 moles of phosphorus
   2. 4.0 moles of iron 
   3. 5.20 moles of fluorine gas
   4. 1.3 moles of hydrochloric acid (HCl)
   5. 7.7 moles of neon
6. Combine the following ions into an ionic compound and calculate the molar mass.
   1. Ammonium ion and sulfide ion
   2. Strontium ion and nitride ion
   3. Aluminum ion and fluoride ion
   4. Calcium ion and iodide ion
   5. Silver ion and oxide ion

Mole Questions

1. What is the molar mass of sodium bicarbonate (baking soda)?
2. How many moles are in a 42g sample of sodium bicarbonate?
3. What is the mass in grams of 0.42 moles of sodium bicarbonate?
4. How many formula units are in a 25g sample of sodium bicarbonate? Hint: Ionic compounds do NOT form molecules, so we use the term formula unit.
5. How many sodium ions are in a 3.2g sample of sodium bicarbonate?
6. What is the molar mass of glycerine (C3H8O3C3H8O3)?
7. How many moles are in a 42g sample of glycerine?
8. What is the mass in grams of 0.42 moles of glycerine?
9. How many molecules are in a 25g sample of glycerine?
10. How many carbon atoms are in a 3.2 g sample of glycerine?
11. Answer the following questions for both caffeine (C8H10N4O2) and sodium phosphate.
    1. Calculate the molar mass of each.
    2. Is each compound covalently or ionically bonded? Explain your reasoning.
    3. We have a pure sample of each compound that weighs 2.3 g. How many moles are present in each sample?
12. There is a 50 g sample of each of the following substances: Ca(NO3)2, NaHCO3 CuCl2
    1. Which sample contains the largest number of formula units?
    2. Which sample contains the largest number of ions?

Writing and Balancing a Chemical Equation

1. Balance the following chemical equations.
   1. \( \ce{Al(s) + H2O(l)→Al(OH)3(s) + H2(g) } \)
   2. \( \ce{N2(g) + O2(g)→NO2(g) } \)
   3. \( \ce{H2CO3(aq)→H2O(l) + CO2(g) } \)
   4. \( \ce{P2O5(s)→P4(s) + O2(g) } \)
   5. \( \ce{N2(g) + H2(g) + Cl2(g)→NH4Cl(s) } \)
2. Balance each of the given combustion reactions.
   1. \( \ce{C6H6(l) + O2(g)→CO2(g) + H2O(g) } \)
   2. \( \ce{C2H2(g) + O2(g)→CO2(g) + H2O(g) } \)
   3. \( \ce{C8H18(l) + O2(g)→CO2(g) + H2O(g) } \)
   4. \( \ce{C4H9OH(l) + O2(g)→CO2(g) + H2O(g) } \)
   5. \( \ce{CH3(CH2)4OCH2CH3(l) + O2(g)→CO2(g) + H2O(g) } \)
3. The next set of chemical equations are NOT properly balanced. Alter the coefficients as needed so that the equations are properly balanced.
   1. \( \ce{N2(g) + H2(g)→2NH3(l) } \)
   2. \( \ce{Ba(OH)2(s) + H2SO4(aq)→BaSO4(s) + H2O(l) } \)
   3. \( \ce{2CH4(g) + N2(g)→HCN(g) + 4H2(g) } \)
   4. \( \ce{8Cl2(g) + 8H2O(l)→2HClO4(aq) + 14HCl(aq) } \)
   5. \( \ce{2PH3(aq) + 2O2(g)→2H3PO4(aq) } \)

Energy and Chemical Reactions

1. Follow the directions in each of the following sets of conversions. Report your answers to two (2) significant figures.
   1. Convert 6.0 grams of fat into kilocalories, and the kilocalories into joules
   2. Convert a sample containing 9.0 grams of carbohydrates into calories, then into kilocalories, then into joules
   3. Convert a 7.0 gram serving of protein into kilocalories, then into joules
   4. Convert a meal consisting of 14. grams of protein and 12. grams of carbohydrates into kilocalories, then joules
   5. Convert a full course serving of 8.0 grams of fat, 8.0 grams of protein and 6.0 grams of carbohydrates into kilocalories, then joules

Pressure

1. Name at least three different units of measurement for pressure and relate them using conversion factors.
2. Perform the following conversions of pressure from one unit to another.
   1. 120 psi into Torr
   2. 6.0 atmospheres into pascals
   3. 2800 mmHg into atmospheres

Gas

1. A helium tank has a volume of 4.0 Liters. The pressure on the tank is 5.0 atmospheres. To save room the helium is transferred directly into a tank with a volume of 1.5 liters. What will the new pressure be in the new tank?
2. If an athlete is training in a high-altitude area where the atmospheric pressure is 0.90 atmospheres and their healthy lung capacity is 3.2 liters, what would the pressure be if they developed a respiratory disease that decreased their lung capacity to 2.5 liters?
3. Answer the following True or False questions.
   1. As pressure increases, volume increases.
   2. As pressure decreases, volume increases
   3. As volume decreases, pressure increases
4. A mixture of the halogen gases has four partial pressures that compose the total pressure. If chlorine gas has a partial pressure of 2.00 atmospheres, bromine gas has a partial pressure of 13.0 psi, fluorine gas has a partial pressure of 800. mmHg and iodine gas has a partial pressure of 900. Torr, what is the total pressure in mmHg? What is the percent composition for each of the gases in the mixture?

Writing Structures

1. Translate the following structures into their condensed formulas.

2. Give the IUPAC name for each of the following compounds.

c. 

3. Translate these expanded structures into their skeletal equivalents.
   1. 
   2. 
   3. 
   4. 

Solution Concentrations

1. Many different biological molecules must be monitored to maintain a healthy body. Perform the following operations to convert one unit of measurement to another.
   1. Blood sugar (glucose) level of 60 mg/dL to g/L
   2. Blood cholesterol level of 185 mg/dL to mcg/mL
   3. Iron level of 142 mcg/dL to mg/L
   4. Blood alcohol level of 10 mg/dL to g/L
   5. Sodium level of 150 mg/dL to mcg/mL
2. What mass in grams of glucose will you need if you wish to make a solution of 5.00% (m/v) of 250 mL?
3. You have 23.0 g of potassium phosphate with which to make a 20.0% (m/v) solution. What volume of solvent will you need to get this concentration?
4. Convert the following quantities to the desired units.
   1. 860 mmol/L to mol/L
   2. 70 mol/dL to mol/L
   3. 8 mol/L to mmol/mL
   4. 900 mmol/mL to mol/L
   5. 17 mol/L to mmol/dL
5. How many moles of hydroxide are there in a 300. mL solution of 0.50 M aluminum hydroxide? How many moles of aluminum are there?
6. A blood test reveals different concentrations of various essential minerals. A concentration of 0.65 mmol/L of copper (II), 0.09 mmol/L of manganese (IV), and 0.80 mmol/L of zinc. For each concentration, convert them to milliequivalents/L.
7. A solution of calcium sulfate has a concentration of 0.20 M. How many equivalents/L of calcium ions are there? How many equivalents/L of sulfate ions?
8. A doctor prescribes a dosage of 150,000 units of medication. 75 mg of the medication is equivalent to 1.0 x 105 units. The method of delivery provides only 50. mg of the active ingredient per mL. How many milliliters of the medication will be administered in each dose?
9. A prescription calls for 20. g of medication for a patient. Two possible suspensions are available, one with a dosage of 7.0g/10. mL and 10.g/25 mL. How many milliliters of each suspension will be needed to meet the dosage the prescription calls for?
10. The dosage is 4.0 mg and must be equally distributed throughout a ten-minute period. If the solution is only available in 3.0 mg/10 mL, what will the flow rate be in mL/min?
11. A doctor calls for a dosage to be increased. Currently the patient is receiving a flow of 50. mL/hr, with the concentration of 30. mg/200. mL. The doctor calls for the dosage, in mg/min, to be increased by 50.%. What will the new flow rate, in mg/min, be?
12. An infant weighing 20. lbs. is prescribed a dose of 100. mg three times a day. A report emerges that the safe dosage of that medication is between 25 and 45 mg/kg of body weight per day. Is the prescribed dosage within the safe limit for the infant?

Converting Between Different Concentration Units

1. Convert a 0.65 % (m/v) calcium chloride concentration to molarity. How many Eq/L of calcium ions are present? How many Eq/L of chloride ions are present?

Colloids and Suspensions

1. Differentiate between the following pairs, which is the colloid and which the solution.
   1. Chocolate milk and rice pudding
   2. Tuna salad and vinegar-based dressing
   3. Light syrup and pureed fruit
   4. Rocky road ice cream and fruit juice
   5. Mashed potatoes and vegetable oil

Membranes, Osmosis and Dialysis

1. Given the following situations, wherein two tanks of different solutions are separated by a semipermeable membrane, determine the direction of the flow of solvent (water).
   1. Solution A contains a 0.40 M concentration of CaCl2, while Solution B contains a 0.45 M concentration of KI
   2. Solution A contains a 1.00 M concentration of NH4Cl, while Solution B contains a 1.00 M concentration of CH2O
   3. Solution A contains 0.20 M NaCl and Solution B contains 0.30 M KCl

Conjugate Acids and Bases

1. For each of the following acids, determine the form of their conjugate bases.
   1. HSO4-
   2. H2CO3 
   3. HF
   4. HPO4 2-
   5. HCOOH
2. For each of the following bases, determine the form of their conjugate acids.
   1. Br -
   2. NO3
   3. S2-
   4. NH3
   5. HCO3-

pH

1. Examine the following pH measures and tell whether they are in the range to be considered acidic, basic or neutral.
   1. 6.8
   2. 13.5
   3. 1.9
   4. 4.2
   5. 9.7
2. Using the formula for converting concentration into pH, determine whether each of the following molarities are acidic, basic or neutral. Remember, pH = -log[H+ ]
   1. 1.0 x 10-7 M H+ 
   2. 4.7 x 10-12 M H+
   3. 6.4 x 10-4 M H+
   4. 7.3 x 10-10 M H+
   5. 9.8 x 10-2 M H+

Carbohydrates

1. Study the following Fischer projections to answer the questions below.

1. Is galactose a D-sugar or an L-sugar?
2. Is mannose a D-sugar or an L-sugar?
3. Choose either one, and sketch it as it would appear if it was an L-sugar.
4. Are these two carbohydrates enantiomers? If not, in how many places do they differ?
5. What is the term to describe the relationship between galactose and mannose?

1. Are any of the following carbohydrates L-sugars? What makes something an L-sugar as opposed to a D-sugar? Rewrite each structure into an L-sugar if they are not already in that conformation.

2. Study these Haworth projections to answer the following for each of them.

1. Is it a furanose or a pyranose?
2. Is it an alpha or beta anomer?
3. Circle the anomeric carbon.

3. Examine the structure of this Fischer projection of D-gulose.

1. Number each carbon from 1 to 6. What number is the anomeric carbon?
2. Circle the –OH group that determines whether it is a D- or L-sugar.
3. Sketch the structure of L-gulose for comparison. Are the two versions of gulose enantiomers of one another or diastereomers?
4. Now sketch the structure of D-glucose for comparison. Are D-gulose and Dglucose enantiomers or diastereomers?

4. Examine the following Haworth projections to answer the questions below.

1. Circle each anomeric carbon
2. Which of the two is the alpha anomer and which is the beta anomer?
3. Are these structures considered enantiomers or diastereomers?
4. Are these monosaccharides reducing sugars? Explain.
5. Can you convert the alpha anomer to a beta anomer? Explain.

5. Some people cannot digest the disaccharide lactose. The term for this is known as lactose intolerance. Lactose is shown below. Answer the following questions.

1. What is the name of the enzyme that would be required for someone to be able to digest lactose?
2. Classify lactose as a mono-, di-, oligo-, or polysaccharide.
3. Label anomeric carbons by circling them. Is lactose a reducing sugar?
4. Draw an arrow pointing to the glycosidic bond. Is the glycosidic bond connected to both anomeric carbons?
5. Classify the glycosidic bonds using the alpha or beta-(#,#) format.
6. If the glycosidic bond is hydrolyzed, what are the names of the monosaccharides produced. Remember to include the alpha or beta classification for the anomeric carbon.