Difference Between Physical and Chemical Properties
Define what a physical property is.
A physical property is a characteristic that can be observed or measured without changing the substance’s identity.
List three physical properties of matter.
color, melting point, density.
Define what a chemical property is.
A chemical property describes a substance’s ability to undergo a specific chemical change.
Identify whether boiling water is a physical or chemical change.
Boiling water is a physical change—it remains H₂O.
Explain Rusting reaction
Rusting is a chemical reaction that happens when iron (like the metal in a nail) reacts with oxygen and water (moisture) from the environment. It’s an example of a redox reaction (oxidation-reduction) and results in the formation of iron oxide, commonly known as rust.
Mention two differences between a physical and a chemical property.
Physical properties do not alter the chemical composition (e.g., melting point), while chemical properties describe how a substance reacts (e.g., flammability).
Describe how the melting point of a substance is measured.
The melting point is measured by slowly heating the substance and recording the temperature at which it changes from solid to liquid.
Mention two examples of chemical properties of matter.
flammability, reactivity with acids.
Describe the signs that indicate a chemical change (odor, color, temperature, precipitate).
Signs of chemical change: new color, heat/light, gas formation, precipitate, or odor.
What Happens During Combustion of Wood?
Wood is mostly made of cellulose, a compound of carbon (C), hydrogen (H), and oxygen (O). When wood burns:
Reactants:
Wood (mainly cellulose)
Oxygen from the air
Products:
Carbon dioxide
Water vapor
Heat and light (energy)
Classify the following properties as physical or chemical: density, combustion, boiling point, oxidation.
Density → Physical
Combustion → Chemical
Boiling point → Physical
Oxidation → Chemical
Apply the concept of density to calculate the density of an object using known mass and volume.
Density = mass ÷ volume.
Explain how reactivity with oxygen indicates a chemical property.
If a metal reacts with oxygen to form rust, that reaction shows a chemical property (reactivity with oxygen).
Apply your knowledge of properties to determine if a change is physical or chemical in an experiment.
Example: Iron rusting shows chemical change; melting wax shows physical change.
Explain oxidation in the apple
Oxidation in an apple is the process that causes a cut apple to turn brown when exposed to air. This is a type of chemical reaction involving enzymes and oxygen.
Explain why a change of state is considered a physical property and not a chemical one.
Change of state is a physical change because the substance remains chemically the same (e.g., water is still H₂O as ice or steam).
Compare the thermal conductivity of two materials and argue which one is better for an experiment.
If Material A conducts heat faster than Material B, Material A has higher thermal conductivity. It's better for applications requiring heat transfer (e.g., cookware).
Interpret an experiment where combustion occurs and identify the chemical properties involved.
In combustion, substances burn and change composition—indicating chemical change involving flammability and reactivity.
Salt dissolving is physical; oxidation of iron is chemical. Compare the dissolution of salt in water with the oxidation of iron.
Salt dissolving is physical; oxidation of iron is chemical.
Justify why flammability is considered a crucial chemical property for handling hazardous materials.
Flammable materials require special storage and handling to prevent fires, showing why understanding chemical properties is essential in safety planning.
Evaluate an experimental scenario and justify whether a chemical or only a physical change occurred.
Given data, students might conclude that bubbling and heat release suggest chemical change while shape changes suggest physical.