Physical Properties
Physical Changes
Mixtures
Chemical Properties
Chemical Changes
100

100: Define a physical property.

  • A property (characteristic) that can be used to describe matter. It can be observed without changing the identity of the substance.
100

100: Why is water condensing a physical change?

  • Condensation is a phase change; the substance remains water (H₂O).
100

100: Define homogeneous and heterogeneous mixtures.

  • Homogeneous mixtures have a uniform composition (like saltwater), while heterogeneous mixtures have different components (like salad).
100

100: Define a chemical property.

  • A characteristic that gives a substance the ability to change into a new substance.
100

100: What is a sign of rust formation?

  • A color change to reddish-brown due to oxidation.
200

200: Find and highlight the mistakes: "Magnetism is seen in all metals."

  • Magnetism is not present in all metals; it is common in ferromagnetic metals like iron and nickel only.
200

200: What type of reaction is melting?

  • Melting is an endothermic reaction as heat is absorbed.
200

200: Why won’t adding iron make a mixture magnetic?

  • In mixtures, substances do not chemically combine, so not all will exhibit magnetic properties.
200

200: Find the mistake: "pH is a physical property."

  • pH is a chemical property, indicating the acidity or basicity of a substance.
200

200: Is toasting bread a physical or chemical change?

  • Chemical Change.
300

300: Name two water-soluble substances.

  • Common examples include salt and sugar.
300

300: Describe shattering glass.

  • Shattering glass is a physical change because no new substance is formed; only physical properties change.
300

300: How to separate salt from water?

  • Use evaporation; salt is soluble and remains after boiling off the water.
300

300: Describe oxidation.

  • Oxidation is the reaction of a substance with oxygen, such as iron forming rust.
300

300: What happens during fermentation?

  • Fermentation is a chemical change that produces gas and changes the odor of the substance.
400

400: Describe salinity differences.

  • Saltwater has a higher salinity than freshwater.
400

400: What happens to energy during phase changes?

  • Energy is added during melting and boiling, while it is released during freezing and condensation.
400

400: Which method first: Evaporation or filtration?

  • Filtration should be used first to remove gravel, as it is insoluble in water.
400

400: What is a sign of flammability?

  • A substance igniting or burning rapidly when exposed to heat or flame.
400

400: What indicates the presence of a base?

  • Phenolphthalein turning pink.
500

500: Identify the physical property: "Pure iodine is violet."

  • Color.
500

500: Explain the cause and effect of adding thermal energy.

  • Adding thermal energy increases the kinetic energy of molecules, causing solids to melt into liquids and liquids to evaporate into gases.
500

500: Describe the difference between mixtures and compounds.

  • Mixtures are combinations of substances that retain their individual properties, while compounds are substances formed when two or more elements chemically bond.
500

500: What is reactivity with another substance?

  • The ability of a substance to undergo a chemical reaction with another substance.
500

500: Describe the glow stick reaction.

  • The chemical reaction produces light and changes color when the inner glass tube is broken, releasing hydrogen peroxide.
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