Answer:
Picture is showing Apparatus for the Experimental Verification of Law of Conservation of Mass. The unchanged mass of the conical flask before and after the reaction supports the Law of Conservation of Mass. This experiment highlights the importance of precise mass measurements, contributing to the understanding of Lavoisier’s Law of Constant Proportions. Variations of this experiment can be conducted using different combinations like copper sulphate with sodium carbonate, barium chloride with sodium sulphate and lead nitrate with sodium chloride.
space, mass
substance
fixed, volume
melting, fusion
1 : Matter is anything that occupies _______ and has _______.
2 : A _______ is a homogeneous material with a consistent composition.
3 : Solids maintain a _______ shape and _______ volume.
4 : When solids turn into liquids, this process is known as _______ or _______.
melting
5 : The _______ point of a pure substance remains consistent and can be a metric to ascertain its purity.
Total Questions: 5
Correct:
- Matter is anything that occupies _______ and has _______. :space, mass
- A _______ is a homogeneous material with a consistent composition. :substance
- Solids maintain a _______ shape and _______ volume. :fixed, volume
- When solids turn into liquids, this process is known as _______ or _______. :melting, fusion
- The _______ point of a pure substance remains consistent and can be a metric to ascertain its purity. :melting
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Answer:
The Kinetic Molecular Theory explains that matter is made up of tiny particles (atoms or molecules) that are in constant motion. In solids, particles are closely packed and vibrate in fixed positions. In liquids, particles are more spaced out and move around each other. In gases, particles are far apart and move freely. This theory helps explain the behaviour of solids, liquids and gases by describing how their particles move and interact with each other.
Answer:
The boiling point of a liquid is the temperature at which it changes from a liquid to a gas throughout the entire liquid. Determining the boiling point is significant because it can help identify substances and assess their purity. It also provides information about the substance’s behaviour under different conditions.
📘 Study Notes
🔑 Key Concepts
- Physical changes alter specific properties of matter without changing its molecular composition.
- Chemical changes alter the molecular composition of a substance, resulting in new properties.
- Physical changes are generally reversible, while chemical changes are usually irreversible.
📚 Important Definitions
- Physical Change: Alters specific properties of matter without changing its molecular composition.
- Chemical Change: Alters the molecular composition of a substance, resulting in new properties.
📝 Examples
- Melting of ice is a physical change.
- Rusting of iron is a chemical change.
- Formation of curd from milk is a chemical change.
- Burning of a candle is a physical change.
📄 Summary Points
- Physical changes are reversible and do not result in the formation of new substances.
- Chemical changes are usually irreversible and lead to the formation of new substances with different properties.
- Physical changes can involve changes in state, color, texture, etc., without altering the composition.
- Chemical changes involve the rearrangement of atoms and the formation of new molecules.
- Energy changes, such as absorption or release of heat, are common in chemical reactions.
📘 Study Notes
🔑 Key Concepts
- Dissolution of Salts in Water: When a solid disappears in water, it is dissolved, and the product is called a solution.
- Solvent: The liquid that dissolves other substances is called the solvent.
- Solute: The substance that dissolves in a liquid is called the solute.
- Solution: A homogeneous product formed by dissolving a solute into a solvent.
- Saturated Solution: A solution that cannot dissolve more solute at a given temperature.
- Unsaturated Solution: A solution that can dissolve more solute at a given temperature.
- Supersaturated Solution: A solution that can hold more solute than a saturated solution at a given temperature.
- Solubility of a Substance: The maximum amount of solute that dissolves in 100g of water at a given temperature to form a saturated solution.
- Importance of Dissolved Gases in Water: Provide taste, aid in respiration of aquatic life, and serve as food for plants.
- Salinity of Seawater: Concentration of salt in seawater and its cycle.
📚 Important Definitions
- Solution: A clear and transparent mixture where solute particles are broken down to molecular size.
- Suspension: A heterogeneous mixture of insoluble particles in a solvent.
- Colloidal Solution: A heterogeneous solution with particles between 10^7 cm and 10^4 cm.
📝 Examples
- Sugar solution, common salt solution, starch solution.
📄 Summary Points
- Dissolution involves a solid disappearing in water to form a solution.
- Solvent dissolves other substances, while solute dissolves in the liquid.
- Saturated solution cannot dissolve more solute at a given temperature.
- Dissolved gases in water have various important functions.
- Salinity of seawater is maintained through a continuous cycle.
📘 Study Notes
🔑 Key Concepts
- Water of crystallisation: Fixed number of water molecules attached to a salt.
- Hydrated substances: Substances with water molecules loosely attached.
- Anhydrous substances: Residue left after heating hydrated substances.
- Deliquescent substances: Salts that absorb water from air.
- Hygroscopic substances: Substances that absorb moisture from air.
- Hard water: Water forming scum instead of lather with soap.
- Soft water: Water lathering freely with soap.
- Temporary hardness: Reversible hardening due to dissolved carbonates.
- Permanent hardness: Irreversible hardening due to sulfates.
📚 Important Definitions
- Water of crystallisation: Fixed number of water molecules attached to a salt.
- Hydrated substances: Substances with water molecules loosely attached.
- Anhydrous substances: Residue left after heating hydrated substances.
- Deliquescent substances: Salts that absorb water from air.
- Hygroscopic substances: Substances that absorb moisture from air.
- Hard water: Water forming scum instead of lather with soap.
- Soft water: Water lathering freely with soap.
- Temporary hardness: Reversible hardening due to dissolved carbonates.
- Permanent hardness: Irreversible hardening due to sulfates.
📝 Examples
- Copper sulphate: CuSO4·5H2O
- Iron sulphate: FeSO4·7H2O
- Sodium carbonate: Na2CO3·10H2O
- Magnesium sulphate: MgSO4·7H2O
- Zinc sulphate: ZnSO4·7H2O
📄 Summary Points
- Water of crystallisation is fixed water molecules with a salt.
- Hydrated substances lose water on heating to become anhydrous.
- Deliquescent substances absorb water from air to form a solution.
- Hard water forms scum, while soft water lathers freely with soap.
- Temporary hardness is reversible, while permanent hardness is not.
📘 Study Notes
🔑 Key Concepts
- Hydrogen can be prepared from electrolysis of water and by reacting metals with acids.
- Hydrogen is essential in various compounds like carbohydrates, fats, and proteins.
- Laboratory preparation of hydrogen involves reacting zinc with dilute sulfuric acid.
- Electrolysis is the process of passing electric current through a compound to bring about a chemical change.
📚 Important Definitions
- Electrolysis: The process of passing electric current through a compound to induce a chemical change.
- Electrodes: Conducting poles in an electrolyte through which current enters and leaves.
- Catalyst: A substance that speeds up a chemical reaction without undergoing a change itself.
📝 Examples
- Hydrogen can be obtained by reacting active metals like potassium with water.
- Zinc reacts with dilute sulfuric acid to produce hydrogen gas.
📄 Summary Points
- Hydrogen is prepared by various methods including electrolysis of water and reacting metals with acids.
- It is an essential component in various compounds found in plants and animals.
- Laboratory preparation of hydrogen involves using zinc and dilute sulfuric acid.
- Electrolysis is a process that involves passing electric current through a compound to bring about a chemical change.
- Catalysts can speed up chemical reactions without undergoing any change themselves.
📘 Study Notes
🔑 Key Concepts
- Physical Properties of Hydrogen Gas:
- Colorless, tasteless, and odorless.
- Lighter than air with a vapour density of 1.
- Insoluble in water.
- Chemical Properties of Hydrogen Gas:
- Combustible but does not support combustion.
- Reacts with oxygen to form water.
- Neutral towards litmus.
- Uses of Hydrogen Gas:
- Welding and cutting purposes.
- Meteorological purposes.
- Manufacture of chemicals.
- Hydrogenation of vegetable oils.
- Extraction of metals.
📚 Important Definitions
- Oxidation: Addition of oxygen or removal of hydrogen from a substance.
- Reduction: Addition of hydrogen or removal of oxygen from a substance.
- Catalyst: A substance that alters the rate of a chemical reaction without being consumed.
📝 Examples
- Combustibility: Hydrogen burns silently in air to form water.
- Reduction Reaction: Hydrogen reduces metallic oxides to form metals.
📄 Summary Points
- Hydrogen has physical properties like being colorless, tasteless, and odorless.
- Chemically, hydrogen is combustible but does not support combustion.
- Uses of hydrogen include welding, cutting, and as a reducing agent in the extraction of metals.