Chemical Bonding Lab

Appearance

UNKNOWN 1
WATCH GLASS / INSPECTION LIGHTVIRTUAL LAB BENCH
Appearance stationAn unknown solid on a watch glass under a laboratory inspection light.
Fresh solid • Room temperature25 °C

AT THE BENCH

Move the inspection light to examine the surface.

Fresh portions. Clean equipment. Repeat any test.
About this simulation

Investigate four representative solids using the six tests in the U3 & U4 Chemical Bonding lab. The unknowns remain unlabeled so you can use their properties as evidence. These are illustrative responses, not measurements of your classroom samples. Melting changes attractions between particles; it does not break the covalent bonds within intact molecules. Real substances have exceptions, so use several tests together.

Heating and solvent observations use accelerated time. Lactose decomposes near its reported melting temperature, and iodine can sublime as it warms. The hot plate stops at 300 °C; a solid that remains unmelted may melt above this range. Real experiments require goggles, ventilation, and your teacher's chemical-handling instructions. Keep cyclohexane away from heat.

Investigate four unknown solids

Choose an unknown and a test. Operate the equipment, compare the responses, and use the evidence to infer the type of bonding.

  1. Appearance: sweep the inspection light across the solid and look for color, texture, and luster.
  2. Solid conductivity: lower both clean probes onto the solid. Read the tester's qualitative response.
  3. Melting behavior: load fresh portions of all four unknowns into separate corners of an aluminum foil boat. Turn on the hot plate and compare the order of changes. Switch off, lift the boat with tongs, and allow it to cool.
  4. In water: weigh 0.10 g, measure 50.0 mL of deionized water, transfer both to a beaker, stir, and immerse the conductivity probe. The probe measures the liquid without touching undissolved solids.
  5. In cyclohexane: measure 5.0 mL, add a spatula-tip portion to a test tube, and stir. Watch five simulated minutes at 30× speed, or advance the clock to the final observation.
  6. Malleability: use the mortar and pestle for Unknown 1 and the scoopula for Unknowns 2, 3, and 4. Observe whether the solid flattens or breaks.

Every station and unknown selection starts a fresh test. The melting station compares all four at once. No observations or student answers are collected or saved.

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