Group Members:
Date:
Time:
Laboratory Activity 1: Measuring the Density of Liquids and Solids
Rationale:
Density is a fundamental property of matter that describes the relationship between mass and volume.
Understanding how to measure the density of various materials helps students identify substances and understand
how they interact in real-world scenarios—such as why some objects float or sink in liquids. This laboratory
activity reinforces the concept of density through direct measurement and analysis using common laboratory
tools.
Objective:

To determine the density of selected solid objects and liquid samples using direct measurement
techniques.

To compare calculated densities with known values to identify materials.

To enhance skills in measurement, data recording, and scientific analysis.
Materials:
For each group:

Triple beam balance or digital balance

Graduated cylinder (100 mL or 50 mL)

Beaker (100 mL)

Water

Isopropyl alcohol (optional, for comparison)

Solid objects (small rock, marble)

Dropper or pipette

Ruler (with mm or cm scale)

Calculator

Paper towels

Lab worksheet
Procedure:
Part A: Determining the Density of Liquids
1. Measure the mass of an empty, dry graduated cylinder. Record this value.
2. Pour 50 mL of water into the graduated cylinder.
3. Measure and record the mass of the graduated cylinder with the water.
4. Subtract the mass of the empty cylinder to find the mass of the water.
5. Calculate the density
6. Repeat steps 1–5 using a different liquid such as isopropyl alcohol (if available).
Part B: Determining the Density of Regular Solids
1. Measure the mass of the solid object using the balance.
2. Measure the dimensions (length, width, height) of the object using a ruler.
3. Calculate the volume of the object
4. Calculate the density:
Part C: Determining the Density of Irregular Solids
1. Measure the mass of the object using the balance.
2. Fill a graduated cylinder with a known volume of water (50 mL).
3. Carefully drop the object into the cylinder and record the new volume.
4. Subtract the initial volume to find the volume of the object by displacement.
5. Calculate the density
Record your Observations
Guide Questions (Answers in 3-5 sentences)
1. What differences did you observe between the densities of water and the other liquid?
2. How do the densities of the solid objects compare with the liquids?
3. Which method (direct measurement vs. water displacement) did you find easier for finding the volume?
4. Based on your results, which objects would float in water? Explain using density.
5. Why is it important to use the same units (grams for mass, mL or cm³ for volume) in density
calculations?
6. Were your calculated densities close to the known densities of the materials? What might account for
differences?
Group Members:
Date:
Time:
Laboratory Activity 2: Making an Ionic Compound – Salt from Baking Soda and Vinegar
Rationale:
One way to understand how ionic compounds form is to create one in the lab. In this activity, students will
produce sodium acetate (an ionic compound) by reacting baking soda (a base) and vinegar (an acid), then
observe the solid salt that forms after the reaction.
Objective:

To observe a chemical reaction that forms an ionic compound

To collect and identify a simple ionic salt (sodium acetate)

To understand how acids and bases can produce ionic compounds
Materials (per group):

1 teaspoon of baking soda (sodium bicarbonate, NaHCO₃)

20 mL vinegar (acetic acid, CH₃COOH)

Beaker or small glass container

Heat source (alcohol lamp or hot plate )

Stirring rod or spoon

Evaporating dish or shallow container

Safety equipment
Procedure:
1. Put on your safety equipment.
2. Pour the vinegar into the beaker.
3. Slowly add the baking soda while stirring. The mixture will fizz—this is carbon dioxide gas being
released.
4. Once the fizzing stops, carefully pour the liquid into an evaporating dish.
5. Place the dish on a hot plate or under gentle heat to allow the water to evaporate (teacher may assist).
6. After the water evaporates, observe the white solid left behind. This is sodium acetate, an ionic
compound.
7. Record your observations
Guide Questions: (Answers in 3-5 sentences)
1. What did you observe when you mixed baking soda and vinegar?
2. What gas was released during the reaction?
3. What is left behind after evaporation?
4. Is the product an example of an ionic compound? Why?
5. What two ions make up sodium acetate?
Group Members:
Date:
Time:
Laboratory Activity 3: Observing Mass Before and After a Chemical Reaction
Rationale:
In any chemical reaction, the total mass of the reactants should equal the total mass of the products. This
activity helps students observe and understand the Law of Conservation of Mass using a reaction between
vinegar and baking soda in a closed system.
Objective:

To measure the mass of substances before and after a chemical reaction

To show that mass is conserved in a chemical reaction

To improve skills in using a balance and recording data
Materials (per group):

1 small plastic bottle or flask with cap (with airtight seal)

1 small balloon

1 tablespoon of baking soda (sodium bicarbonate, NaHCO₃)

30 mL vinegar (acetic acid, CH₃COOH)

Funnel or small paper cone

Measuring spoon

Digital or triple beam balance

Tape and marker
Procedure:
1. Use tape and a marker to label your plastic bottle and balloon with your group name.
2. Carefully pour the vinegar into the plastic bottle using a funnel.
3. Use a funnel or paper cone to place 1 tablespoon of baking soda into the balloon.
4. Without mixing the two substances yet, stretch the balloon over the bottle’s opening (do not let the
baking soda fall in).
5. Place the entire setup (bottle with vinegar and balloon with baking soda attached) on the balance.
Record the total mass before reaction.
6. Carefully lift the balloon to dump the baking soda into the vinegar.
7. Hold the balloon tightly as it inflates from the carbon dioxide gas. Wait until the reaction stops fizzing.
8. Place the setup back on the balance and record the total mass after reaction.
9. Compare the before and after masses.
Guide Questions: (Answer in 3-5 Sentences)
1. What gas was produced during the reaction?
2. Was there a change in the total mass before and after the reaction?
3. If the mass stayed the same, what does this tell you about matter in a closed system?
4. What would happen if the bottle was open during the reaction?
5. How does this experiment show the Law of Conservation of Mass?
Group Members:
Date:
Time:
Laboratory Activity 4: Modeling Graham’s Law Using Scent Diffusion
Rationale:
Graham’s Law states that lighter gas particles diffuse faster than heavier ones. While actual effusion
experiments require pressurized containers, students can safely model the concept using the diffusion of
different scents in air. By observing how quickly various vapors spread in the air, students can relate scent
intensity and speed to molecular mass and size.
Objective:

To model the behavior of gases during diffusion

To compare the rate at which different gases (scents) travel in air

To understand the relationship between molar mass and diffusion speed
Materials (per group or demo stations):

Cotton balls (2 per trial)

Clear plastic or glass tube (e.g., 1-meter plastic tube or long box)

Stopwatch or timer

Tape measure or ruler

Dropper bottle of vinegar (acetic acid vapor, ~60 g/mol)

Dropper bottle of perfume or rubbing alcohol (ethanol, ~46 g/mol)

Optional: vanilla extract or air freshener as additional scent

Plastic gloves (optional)

Lab worksheet
Procedure:
1. Label the ends of the plastic tube as "End A" and "End B."
2. At “End A,” place a cotton ball soaked with vinegar. At “End B,” place a cotton ball soaked with
rubbing alcohol or perfume.
3. Immediately start the timer as both cotton balls are inserted.
4. Have two students stand at equal distances from the ends of the tube. Each student will note the time
when they first detect a scent.
5. Record which scent arrives first and how long each took.
6. Repeat using different scent combinations if available.
7. Compare the results with the molar masses of the main compounds.
Guide Questions: (Answer in 3-5 sentences)
1. Which scent reached your nose first?
2. What is the approximate molar mass of the vapor that diffused faster?
3. How does this relate to Graham’s Law?
4. What factors might affect how quickly the scent travels (temperature, air currents, etc.)?
5. If you used a heavier gas like CO₂, what would you expect?