Experiment 1: Measuring Mass...................................................................................................................... 1

Procedure A: Determination of the Mass of Metal Solids..................................................................................................................... 1

Procedure B: Determination of the Mass of a Reagent: Sodium Chloride........................................................................................ 2

Experiment 2: Measuring Density.................................................................................................................. 3

Procedure A: Measuring the Density of Regular Solids......................................................................................................................... 3

Procedure B: Measuring the Density of Water........................................................................................................................................ 4

Procedure C: Measuring the Density of Methanol................................................................................................................................. 4

Procedure D: Measuring the Density of Sodium Chloride (NaCl) Solutions...................................................................................... 5

Experiment 3: Measuring Boiling Points......................................................................................................... 9

Procedure A: Calibrating a Thermometer................................................................................................................................................ 9

Procedure B: Measuring the Boiling Point of an Alcohol.................................................................................................................... 10

Experiment 4: Chemical Reactions I............................................................................................................. 13

Procedure A: Reactions of the Alkali Metals (Group 1) and Alkaline Earth Metals (Group 2) with Water............................... 13

Procedure B: Two Reactions of Magnesium Metal............................................................................................................................. 15

Procedure C: Flame Tests: Atomic Emission of Group 1 and Group 2 Metals............................................................................... 16

Procedure D: Two Sublimations.............................................................................................................................................................. 16

Experiment 5: Chemical Reactions II............................................................................................................. 17

Procedure A: Air Oxidation or Combustion Reactions........................................................................................................................ 17

Procedure B: Decomposition Reactions................................................................................................................................................. 17

Procedure C: Oxidation-Reduction (Redox) Reactions...................................................................................................................... 18

Procedure D: Precipitation Reactions; an Insoluble Product.............................................................................................................. 19

Procedure E: An Acid-Base or Neutralization Reaction...................................................................................................................... 19

Experiment 6: Precipitation Reactions.......................................................................................................... 21

Experiment 7: Oxidation-Reduction (Redox) Reactions................................................................................ 25

Procedure A: Oxidation of Magnesium Metal...................................................................................................................................... 25

Procedure B: Oxidation-Reduction of Copper and Zinc..................................................................................................................... 26

Procedure C: Oxidation-Reduction of Ammonium Dichromate....................................................................................................... 27

Procedure D: Oxidation-Reduction of Halogens.................................................................................................................................. 28

Experiment 8: Stoichiometry of an Acid-Base Reaction.................................................................................. 29

Experiment 9: An Assay of Vinegar............................................................................................................... 33

Procedure A: Preparation of the 0.1 M NaOH Titrant:....................................................................................................................... 33

Procedure B: Buret Practice...................................................................................................................................................................... 34

Procedure C: Titration of Vinegar........................................................................................................................................................... 34

Experiment 10: Classes of Organic Compounds............................................................................................ 37

Procedure A: Air Combustion of Hexane.............................................................................................................................................. 38

Procedure B: Bromination of Double Bonds in Unsaturated Hydrocarbons.................................................................................. 38

Properties and Reactions of Six Alcohols: Functional Groups........................................................................................................... 38

Procedure C: Water Solubility of Alcohols............................................................................................................................................ 39

Procedure D: Air Combustion of Ethanol.............................................................................................................................................. 39

Procedure E: Lucas Test for Alcohols..................................................................................................................................................... 39

Structures of Five Aldehydes and Ketones............................................................................................................................................ 40

Properties of Two Organic Acids.............................................................................................................................................................. 41

Procedure F: pH of Organic Acids........................................................................................................................................................... 41

Properties of an Organic Base or Amine................................................................................................................................................ 42

Procedure G: pH of Organic Bases.......................................................................................................................................................... 42

Experiment 11: Organic Synthesis of Aspirin................................................................................................ 43

Procedure A: Preparation of Aspirin....................................................................................................................................................... 44

Procedure B: Bicarbonate Test for an Acid........................................................................................................................................... 44

Procedure C: Iron (III) Test for Salicylic Acid...................................................................................................................................... 45

Procedure D: Triboluminescence of Methyl Salicylate....................................................................................................................... 45

Experiment 1: Measuring Mass

Name _____________ Lab Partner(s) ________________________ Date __________

All matter has mass. Mass is the fundamental property of matter. Energy, such as heat and light, does not have mass. If something has mass, it is matter! In this experiment, you will measure the mass of matter in a few solid states and shapes. For a reference on mass, see your text: Zumdahl, Introductory Chemistry: A Foundation, Chapter 2.

The unit of mass in the SI (metric) system of units is the gram. The SI abbreviation for gram is ‘g’. A measurement of mass can be written, for example, as ’10.27 g’ . Mass is measured by using a balance or scale; chemists usually call them balances. A balance actually measures weight, not mass, but is calibrated in terms of mass. We often use the terms ‘mass’ and ‘weight’ interchangeably, but they are not really the same thing.

Prelab Question 1: A pencil is taken from the surface of the earth to the space station. Does its mass change? Does its weight change? Explain.

Prelab Question 2: Show how many mg (milligrams) are in 0.43 g by using a unit factor relating g and mg:

Procedure A: Determination of the Mass of Metal Solids

From our collection of solid objects, choose three objects. Or, choose your own object, of about the same size and weight. You will weigh the objects on two different balances and compare the results. Use at least one electronic balance.

Choose the first balance. While nothing is on the balance pan, if it is an electronic balance, ‘zero’ it either by pressing the ‘zero’ or ‘tare’ button. If it is a triple-beam balance, adjust the zero knob to the left under the pan until the pointer points to ‘0’, the balance mark.

Observation A1: Record the manufacturer’s name, model, and serial number of the first balance:

Obtain a 250 mL beaker and place it on this balance.

Observation A2: Record the mass of the beaker (g). This is called the ‘tare weight’, or mass of the container:

Question A1: The precision of an instrument is the smallest change in mass that can be seen on the display. What’s the precision of your balance in grams ?

Question A2: What’s the precision of the balance in mg? Use the method from Prelab Question 2:

Place each of the objects in the ‘tared’ beaker and, on the same balance, measure the total mass of the tared container and the object. This mass is called the ‘gross weight’. The mass of the object, the ‘net weight’, is given by:

Gross Weight - Tare Weight = Net Weight

Observations A3:

Object No.	Description of object	Gross Weight = object + container (g)	Tare Weight of container (g)	Net Weight or mass of object (g)
1
2
3

Now choose a second balance and ‘zero’ it as above.

Observation A4: Record the manufacturer’s name, model, and serial number of the second balance:

Place the 250 mL beaker on this balance.

Observation A5: Record the tare weight of the container:

Again, place each of the objects in the tared beaker and, on the second balance, measure the total mass of the tared container and the object.

Observations A6:

Object No.	Description of object	Gross Weight = object + container (g)	Tare Weight of container (g)	Net Weight or mass of object (g)
1
2
3

Question A3: Now, calculate the difference and the percent difference between the net weights measured on the two balances. The difference and percent difference may be positive or negative; keep the sign on the number.

Percent (%) difference = (Mass on first balance – Mass on second balance) * 100
Mass on first balance

Object No.	Net Weight on Balance 1 (g)	Net Weight on Balance 2 (g)	Difference (g)	Percent Difference (%)
1
2
3

Procedure B: Determination of the Mass of a Reagent: Sodium Chloride

Most chemical reagents (pronounced ‘ree-agents’) are powders, lumps, crystals, or otherwise loose solids which benefit from using a tared container to contain them. In this procedure, you will ‘tare’ a weighing boat using the tare function of a top-loading balance.

Obtain a ‘weighing boat’ as a container, and a box of sodium chloride (NaCl), table salt grade. Place the weighing boat on an electronic balance and press the ‘Tare’ or ‘Zero’ button. This sets the tare weight of the boat to ‘0.00’ g. The boat really does not have a mass of 0.00 g, but the balance now weighs anything placed in the boat from this zero gram reference. This is called ‘taring the container’.

Now, weigh out about 5 g of the NaCl. Record the mass to the precision of the balance (g). Sometimes, this instruction is written as ‘Weigh exactly about 5 g”. It just means, don’t waste time trying to weigh 5.00 g; anything near is OK.

Observation B1: Record the mass of NaCl you weighed out (g):

Observation B2: Wave your hand vigorously over the pan of the balance. What happens? How could this cause an error in the measured mass?

Experiment 2: Measuring Density

Name _____________ Lab Partner(s) ________________________ Date __________

All matter has mass, volume, and thus also has density: mass/volume. In this experiment, you will measure the density of matter in various solid and liquid states and shapes.

For a reference on density, see your text: Zumdahl, Introductory Chemistry: A Foundation, Chapter 2.8.

Prelab Question 1: How many cm³are in 1 mL?

Prelab Question 2: How many cm³ are in 1 cc?

Procedure A: Measuring the Density of Regular Solids

From our collection of metal cubes and cylinders, choose one cube and one cylinder.

Observation A1: Find the dimensions of the cube, to the nearest 0.1 cm:

Width (W): Length (L): Height (H):

Question A1: The volume of a rectangular solid = WLH. Show how to calculate the volume of the cube, in cm³.

Observation A2: What is the mass of the cube, in g?

Question A3: What is the density of the cube in g/cm³? Show your calculation.

Observation A3: Find the dimensions of the cylinder, to the nearest 0.1 cm:

Diameter (d): Height (h) :

Question A4: The volume of a cylinder = π (0.5 d)² h. Show how to calculate the volume of the cylinder, in cm³.

Observation A4: What is the mass of the cylinder, in g?

Question A5: What is the density of the cylinder in g/cm³? Show your calculation.

Procedure B: Measuring the Density of Water

Place a dry 25 mL graduated cylinder on a balance and tare it. From a wash bottle, add reagent water to a volume between 20 and 25 mL. If you spill any on the balance, wipe it off before recording the mass.

Observation B1: Record the mass of the water to the nearest 0.01 g:

Observation B2: Record the volume of the water to the nearest 0.2 mL:

Question B1: From Observations B1 and B2, calculate the density of reagent water:

Observation B3: Measure the temperature of the water and record, in ºC:

Question B2: From Table 1, p8, for the temperature nearest recorded in Observation B3, find the density of water, in g/mL:

Question B3: Look at the table. As the water gets colder, how does the density change?

Procedure C: Measuring the Density of Methanol

CAUTION! Methanol is flammable, and poisonous if ingested. Dispose of down the drain, flushing with tap water.

Empty and shake as dry as possible the 25 mL graduated cylinder. Again, place it on a balance and tare it. From a dropper bottle, add methanol (methyl alcohol) to a volume between 20 and 25 mL. If you spill any on the balance, wipe it off before recording the mass.

Observation C1: Record the mass of the methanol to the nearest 0.01 g:

Observation C2: Record the volume of the methanol to the nearest 0.2 mL:

Question C1: From Observations C1 and C2, calculate the density of methanol:

Procedure D: Measuring the Density of Sodium Chloride (NaCl) Solutions

Here you will prepare three aqueous or water solutions of sodium chloride, table salt grade, of three different concentrations, 5 %, 15 %, and 25 % (w/v). ” (w/v)” means “weight/volume”, the weight of the solute NaCl divided by the total volume of the solution you end up with. You will weigh out the required amount of NaCl directly into a tared 25 mL graduated cylinder, then add the water and dissolve the salt. You’ll then record the total mass of the solution and calculate the density.

Here’s how to make a 5 % (w/v) NaCl solution. Bring the 25 mL graduated cylinder and the NaCl to the balance. Put the cylinder on the balance, tare it, then weigh 1.25 g NaCl into the cylinder. Why 1.25 g NaCl? Look at this:

5 % (w/v) means 5 g NaCl solute . But you only want 25 mL of solution, so
100 mL solution

5 g NaCl solute = 1.25 g NaCl = 5 % (w/v)
100 mL solution 25 mL solution

After you weigh out the NaCl, from a wash bottle add reagent water, put Parafilm over the end, and invert the cylinder until the NaCl is dissolved. Then, add reagent water to the 25.0 mL mark and invert again. Remove the Parafilm, place the cylinder back on the balance and record the total weight of the solution.

Observations

Complete the following table. % Error = Measured Density – Handbook Density x 100. This kind of error can be + or –. Handbook Density

Look up the “Handbook Density” in Table 2, p8.

NaCl concentration, % (w/v)	Mass of NaCl solute (g)	Mass of solution (g)	Volume of solution (mL)	Density of solution (g/mL)	Handbook density, g/mL	% Error
0.00 % (pure water, from Procedure B)
5.0 %
15 %
25 %

Now, plot this data on page 7.