Chemistry

Icy Hot Lab

Safety

Wear your safety goggles at all times! Keep loose clothing and hair back and

away from the Bunsen burner flame. The beakers will get hot! Use the beaker

tongs to remove the beaker and dispose of boiling water in the sink.

While you wait Sketch a diagram illustrating the particles

of solid water (ice), liquid water, and water vapor (gas).

Describe the shape, volume, and mass of water as it changes from one phase (state) to the next. For example: Solid water has a constant shape – meaning the cubes of ice hold their shape when dumped onto the table.

While you wait

Pick up a copy of the Energy and Kinetic Theory of Matter Reading.

Read page 1. In your chemistry journal, list the three guiding principles used to understand energy.

Read page 2. Use a graphic organizer to compare / contrast money and energy.

Energy Reading page 2

What are the three energy “accounts” used to explain changes in substances or their arrangements in chemistry.

What are the three ways to transfer energy into or out of a substance?

Law of Conservation of Energy

Energy can be transferred from one “account” to another during chemical or physical processes.

Total energy (like mass) before the change equals the total energy (mass) after the change as long as no energy (mass) enters or leaves the system.

1st Law of Thermodynamics

If energy is transferred into or out of the system, the change in energy equals the energy transferred by heating, working, or radiating.

ΔE = Q + W + R

Kinetic Theory of Matter

Matter is made up of tiny particles that are in constant motion.

Kinetic Theory of Matter Simulation

Kinetic Theory of Matter

These particles exert long range attractions and short range repulsions on each other. Attractions reduce the interaction energy (Ei) while repulsions increase interaction energy.

Phase Change Simulation

Kinetic Theory of Matter

A warmer sample has (on average) faster moving particles than a cooler sample.

Icy Hot Lab Results

Energy Transferred (Heat)

Kinetic E

nergy

Discussion Questions: Chemical or Physical Change? Was the observed phase changes a

chemical change of a physical change? How do you know?

Endothermic change – Change caused by the transfer of energy (heat) into a substance.

Exothermic change – Change caused by the transfer of energy (heat) out of a substance.

Where the phase changes you observed in the lab exothermic or endothermic?

Discussion Questions: Endothermic or Exothermic Change?

Discussion Questions: Kinetic Energy or Interaction Energy? Was the energy transferred to the

substance stored as kinetic energy? How can you tell from the Temperature vs. Time graph?

Was the energy transferred to the substance stored as interaction energy? How can you tell from the Temperature vs. Time graph?

Discussion Questions: Heating Slowly or quickly? How would the Temperature vs. Time

graph change if we used two bunsen burners instead of one?