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What type of observation is 'the water is 98°C'?
What is a hypothesis?
What is the smallest possible unit of an element?
Atom
A theory has been proven with absolute certainty.
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Match the following physical properties with their definitions:
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Matter is anything that has mass and occupies ______.
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Which of the following is an intensive physical property?
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What happens to the growth of plants when watered with a 10% detergent solution according to the hypothesis?
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What is a quantitative observation?
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What is a qualitative observation?
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What is a hypothesis?
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What differentiates a theory from a law?
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What is matter?
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Match the following terms with their definitions:
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Which of the following are intensive properties? (Select all that apply)
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Which of the following ions is negatively charged?
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What are homogeneous mixtures?
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What is the role of a solute in a solution?
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What is distillation used for?
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Temperature remains constant during phase changes.
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What occurs at the boiling temperature?
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Study Notes
Observations in Science
- Quantitative Observations involve numerical data, such as mass, temperature, and density (e.g., “The water is 98°C”).
- Qualitative Observations are non-numerical and include attributes like color, taste, and texture (e.g., “The water is hot”).
- Interpretation (Inference) refers to conclusions drawn based on observations.
Hypothesis, Theory, and Law
- Hypothesis: An educated guess that explains experimental results; must be tested (e.g., “Plants watered with a 10% detergent solution will experience negative growth”).
- Theory: A well-supported explanation of phenomena developed from multiple hypotheses; cannot be definitively proven (e.g., Theory of Continental Drift, Big Bang Theory).
- Law: A statement based on repeated observations; often mathematical and describes what happens without explaining why (e.g., Ohm’s Law, Law of Conservation of Mass).
Properties of Matter
- Matter: Anything that has mass and occupies space; energy does not qualify as matter.
- Pure Substance: Contains only one type of element or compound, less common in nature.
- Mixture: Consists of two or more types of substances, commonly found.
Key Definitions
- Atom: The smallest unit of an element retaining its properties.
- Element: A substance that cannot be broken down further by chemical means, consisting of one type of atom.
- Molecule/Compound: A cluster of two or more atoms bonded together.
Physical Properties of Matter
- Extensive Properties: Depend on the amount of substance (e.g., mass, volume, length).
- Intensive Properties: Independent of the amount of substance (e.g., color, density, melting point).
Detailed Physical Property Definitions
- Hardness: Resistance to abrasion or scratching.
- Malleability: Ability to be shaped into thin sheets.
- Ductility: Ability to be drawn into wires.
- Lustre: Reflection of light by a solid, described as metallic, glassy, oily, etc.
- Viscosity: Resistance of a fluid to flow; low viscosity indicates fast flow, while high viscosity indicates slow flow.
- Diffusion: Intermingling of fluids due to motion; applies to gases and liquids.
Examples of Physical Properties
- Intensive: Colour, smell, melting point, density, solubility.
- Extensive: Mass, temperature, volume.
Concept of Solubility
- Solubility: The ability of a substance to dissolve in another substance, crucial for understanding mixtures and solutions.
Types of Observations
- Quantitative observations involve numerical data, e.g., "The water is 98°C."
- Qualitative observations consist of non-numerical data, e.g., "The water is hot."
- Interpretation or inference is the conclusion drawn from observations.
Hypothesis
- A hypothesis is an unproven assumption aimed at explaining experimental results.
- It is an educated guess based on prior observations or initial experiments.
- Example: "If plants are watered with a 10% detergent solution, their growth will be negatively affected."
Theory and Law
- A theory is a tested explanation for why natural phenomena occur, developed from multiple hypotheses.
- Theories cannot be definitively proven but are supported by substantial evidence (e.g., Theory of Continental Drift, Big Bang Theory).
- A law describes what happens in nature based on repeated experiments, often in mathematical terms, allowing for predictions (e.g., Ohm’s Law, Law of Conservation of Mass).
Physical Properties of Matter
- Matter is anything that has mass and occupies space; if it’s not matter, it’s energy.
- Substances can be classified as pure substances (one type of element/compound) or mixtures (two or more substances).
- Key definitions: An atom is the smallest unit of an element, an element cannot be separated chemically, and a molecule/compound is a group of two or more atoms bonded together.
- Physical properties are categorized into extensive (depends on the amount, e.g., mass) and intensive (independent of the amount, e.g., color).
Definitions of Physical Properties
- Hardness: Resistance to scratching.
- Malleability: Ability to be shaped into thin sheets.
- Ductility: Ability to stretch into wires.
- Lustre: Light reflection from a solid.
- Viscosity: Fluid's resistance to flow.
- Diffusion: Intermingling of fluids due to motion.
Intensive vs. Extensive Properties
- Intensive properties include density, color, smell, and melting point.
- Extensive properties include mass, temperature, and volume.
Ions
- Ions are charged elements, which can be positively (cations, e.g., Na+) or negatively charged (anions, e.g., Cl-).
- Polyatomic ions consist of multiple atoms, e.g., OH-.
Ion Charge Changes
- Ion charge changes occur due to fluctuations in electron count while protons and neutrons remain constant.
- Example: Aluminum loses 3 electrons resulting in a +3 charge, while oxygen gains 2 electrons resulting in a -2 charge.
Mixtures
- Homogeneous mixtures are uniform in composition, including solutions (e.g., air, salt water).
- Heterogeneous mixtures present varied composition (e.g., granite, sea water).
Solutions
- Components of a solution: solute (dissolved substance) and solvent (substance doing the dissolving, present in greater amount).
- Aqueous solutions utilize water as the solvent.
- A precipitate is a solid formed during a chemical reaction.
Separation Methods
- Separation methods for mechanical mixtures are based on physical properties, e.g., gravity separation, chromatography.
- Filtration is applicable when the solid is desired and liquid is not; distillation separates liquids by boiling points.
Separation Techniques
- Solvent extraction is effective for immiscible solvents.
- A separatory funnel is used for heterogeneous mixtures.
Phase Changes
- Melting temperature (MP), freezing temperature (FP), boiling temperature (BP), and condensation temperature (CP) describe state changes.
- Temperature remains constant during phase changes.
Temperature Behavior of Pure Solids
- Heating a solid results in decreased solid mass as the liquid phase increases.
- Phase change completion is identifiable through continuous temperature during the transition.
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Description
Test your knowledge on different types of observations in science, as well as the concepts of hypothesis, theory, and law. This quiz covers the essentials of matter and its properties. Challenge yourself and see how well you understand these foundational scientific principles!
