Chemistry 11–12 · Year 11

Weighing out 0.100 mol of elements and compounds: a mole display

Module 2: Introduction to Quantitative Chemistry

PracticalLow risk

The idea

Equal amounts in moles contain equal numbers of particles but have different masses, because the mass of each particle differs; the molar mass converts one to the other.

What you need

Electronic balance reading to 0.01 g, weighing boats, spatulas
Carbon (graphite powder), magnesium ribbon or turnings, sulfur powder, iron filings, copper turnings, zinc granules, sodium chloride, calcium carbonate, sucrose, copper(II) sulfate pentahydrate, deionised water, about 40 g of each solid
Labelled 50 mL beakers or clear vials, eleven; 10 mL measuring cylinder for the water
Periodic table with atomic weights

How to do it

Calculate the molar mass of each substance from the periodic table and the mass of 0.100 mol of each.
Weigh out 0.100 mol of each solid into a labelled vial to 0.01 g, and measure 0.100 mol of water by volume (density 1.00 g/mL).
Arrange the vials in order of mass and, beside each, write the mass, the number of moles and the number of particles (atoms, formula units or molecules).
Compare the vials by eye: note that the volumes and masses differ widely although each holds the same number of particles.
Answer: how many moles of oxygen atoms are in the calcium carbonate vial, and how many water molecules are in the copper(II) sulfate pentahydrate vial.
Return the solids to their stock containers (or keep the display sealed and labelled for the class).

What you should see

Each vial holds 0.100 mol, 6.022e+22 particles, with masses: carbon (graphite) 1.20 g, magnesium 2.43 g, sulfur 3.21 g, iron 5.58 g, copper 6.35 g, zinc 6.54 g, sodium chloride 5.84 g, water 1.80 g, calcium carbonate 10.01 g, sucrose 34.23 g, copper(II) sulfate pentahydrate 24.97 g. The calcium carbonate vial holds 0.300 mol of oxygen atoms; the copper(II) sulfate pentahydrate vial holds 0.500 mol of water, 3.011e+23 molecules. Each vial is weighed out until the balance reads its calculated mass to 0.01 g.

What changes

This activity lists no variables to change, measure and keep the same.

Common misconceptions

Each of these ideas is wrong, and the activity is a chance to test it.

A mole of every substance has the same mass (it has the same number of particles; the mass is the molar mass).
A mole of water and a mole of sucrose take up the same volume (0.100 mol of water is 1.80 mL; of sucrose it is a heap of over 34 g).
The mole is a mass unit (it is an amount of substance: a count of particles, 6.02214076e23 per mole).

Safety card

Low riskLearners carry it out

Hazards

copper(II) sulfate is harmful if swallowed and irritant
fine powders (graphite, sulfur) can be inhaled
magnesium and sulfur powders are flammable

Controls

weighing boats and spatulas; no tasting or handling of solids
no flames at the weighing bench
eye protection
wash hands

Note

NSW Department of Education Chemical Safety in Schools (CSIS) package, 2021 Technical Update: Section 1.7 (risk assessment) and Volume 2 Appendix D (generic assessment advice and DoE chemical categories); record a RiskAssess (riskassess.com.au) risk assessment before the lesson and check the school's hazardous chemical register (CSIS Section 1.9) for local restrictions.

Curriculum references

The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.

Chemistry Stage 6 Syllabus (2017), NESA; the current syllabus, taught in 2026 (codes read from the syllabus document)CH11-9 CH11/12-4 CH11/12-6
Chemistry 11-12 Syllabus (2025), NESA; implemented from 2028, not yet taughtCH-11-02 CH-11WS-04
Australian Curriculum v9No Australian Curriculum v9 code is listed.

Sources

The pages the author read to write this activity.

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