Physical and Chemical Changes
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Questions and Answers

What indicates a permanent change in a substance?

  • It can be reversed easily
  • New products are formed (correct)
  • It absorbs heat only
  • The composition remains unchanged

    • Which of the following is a characteristic of a physical change?

  • Mass of substance is changed
  • Reversible under certain conditions (correct)
  • New substances are formed
  • Altered composition of molecules

    • Which statement is true regarding chemical changes?

  • They can be easily reversed
  • The mass remains unchanged
  • It is accompanied by a change in properties (correct)
  • Only heat is absorbed without light emission

    • What happens to the composition of molecules during a chemical change?

    <p>Molecules are altered permanently</p> Signup and view all the answers

    Which of the following best describes a physical change?

    <p>Composition of substances remains unchanged</p> Signup and view all the answers

    What defines a physical change?

    <p>It is temporary and easily reversible.</p> Signup and view all the answers

    Which of the following is an example of an irreversible change?

    <p>Burning of magnesium</p> Signup and view all the answers

    How do slow changes differ from fast changes?

    <p>Slow changes occur gradually over time.</p> Signup and view all the answers

    Which change occurs periodically at regular intervals?

    <p>Change of seasons</p> Signup and view all the answers

    What characterizes a chemical change?

    <p>New substances are formed.</p> Signup and view all the answers

    Which of the following describes undesirable changes?

    <p>They result in useless outcomes.</p> Signup and view all the answers

    Which example illustrates a reversible change?

    <p>Melting of ice</p> Signup and view all the answers

    What is true about non-periodic changes?

    <p>They do not occur periodically.</p> Signup and view all the answers

    Which statement accurately reflects the nature of a chemical change?

    <p>Chemical changes are permanent and cannot be reversed.</p> Signup and view all the answers

    In a physical change, what remains unchanged?

    <p>The overall mass of the substance.</p> Signup and view all the answers

    Which of the following characteristics is NOT associated with chemical changes?

    <p>The chemical properties of substances remain the same.</p> Signup and view all the answers

    What is a defining feature of physical changes compared to chemical changes?

    <p>They can be easily reversed under certain conditions.</p> Signup and view all the answers

    What can be concluded about the total mass during a chemical change?

    <p>The total mass remains constant despite substance changes.</p> Signup and view all the answers

    What is a key characteristic of a physical change?

    <p>Easily reversible state transformation</p> Signup and view all the answers

    Which of the following best describes irreversible changes?

    <p>Changes that result in the formation of new, permanent substances</p> Signup and view all the answers

    What is an example of a fast change?

    <p>Burning of magnesium</p> Signup and view all the answers

    Which type of change occurs at regular intervals?

    <p>Periodic changes</p> Signup and view all the answers

    How are desirable changes defined?

    <p>Changes that yield useful results</p> Signup and view all the answers

    Which change cannot be reversed by changing conditions?

    <p>Breaking of glass</p> Signup and view all the answers

    What distinguishes chemical changes from physical changes?

    <p>Chemical changes produce new substances</p> Signup and view all the answers

    What type of change is the melting of ice classified as?

    <p>Reversible change</p> Signup and view all the answers

    Which statement accurately describes the outcome of a chemical change?

    <p>The composition of the substance cannot revert to its original state.</p> Signup and view all the answers

    What best distinguishes physical changes from chemical changes?

    <p>Physical changes do not alter the composition of molecules.</p> Signup and view all the answers

    Which feature is NOT a characteristic of a chemical change?

    <p>Reversible by simply changing conditions.</p> Signup and view all the answers

    In the context of chemical changes, which of the following is generally true?

    <p>Heat is evolved or absorbed during the process.</p> Signup and view all the answers

    What would be an indicator of a physical change rather than a chemical change?

    <p>The composition of the substance remains unchanged.</p> Signup and view all the answers

    Which statement accurately describes reversible changes?

    <p>They can be reversed by a change in conditions.</p> Signup and view all the answers

    Which of the following examples is a physical change?

    <p>Melting of ice</p> Signup and view all the answers

    What characteristic is true of chemical changes?

    <p>They produce new substances.</p> Signup and view all the answers

    Which of the following best illustrates an undesirable change?

    <p>Formation of rust on metal</p> Signup and view all the answers

    Which of these is true regarding fast changes?

    <p>They can happen in an instant.</p> Signup and view all the answers

    Which statement about physical and chemical changes is correct?

    <p>Chemical changes are not easily reversible.</p> Signup and view all the answers

    Which of the following is an example of a periodic change?

    <p>Seasons changing</p> Signup and view all the answers

    Which of the following describes an irreversible change?

    <p>Burning of magnesium</p> Signup and view all the answers

    The burning of magnesium forms magnesium ______.

    <p>oxide</p> Signup and view all the answers

    A physical change has an unaltered composition of the ______ of the substance.

    <p>molecules</p> Signup and view all the answers

    A chemical change is a ______ change that is not reversed by the reversal of conditions.

    <p>permanent</p> Signup and view all the answers

    During a chemical change, the composition and properties of the substance ______.

    <p>change</p> Signup and view all the answers

    In a physical change, there is no change in ______ of the substance.

    <p>mass</p> Signup and view all the answers

    A physical change is generally ______ and easily reversible.

    <p>temporary</p> Signup and view all the answers

    Chemical changes are ______ and involve the formation of new substances.

    <p>permanent</p> Signup and view all the answers

    Melting of ice is an example of a ______ change.

    <p>physical</p> Signup and view all the answers

    Burning of magnesium is classified as a(n) ______ change.

    <p>irreversible</p> Signup and view all the answers

    Changes that occur periodically at regular intervals are known as ______ changes.

    <p>periodic</p> Signup and view all the answers

    A seed growing into a tree is an example of a ______ change.

    <p>slow</p> Signup and view all the answers

    Desirable changes produce ______ results and can be brought about by nature or man.

    <p>useful</p> Signup and view all the answers

    Irreversible changes are changes that ______ be reversed by changes in conditions.

    <p>cannot</p> Signup and view all the answers

    A chemical change has an altered composition of the ______ of the substance.

    <p>molecules</p> Signup and view all the answers

    During a physical change, there is no change in the ______ of the substance.

    <p>mass</p> Signup and view all the answers

    Chemical changes are usually ______ and involve the formation of new substances.

    <p>permanent</p> Signup and view all the answers

    A physical change is generally ______ and easily reversible.

    <p>temporary</p> Signup and view all the answers

    The burning of magnesium results in magnesium ______.

    <p>oxide</p> Signup and view all the answers

    Physical changes are ______, easily reversible, and do not alter the composition of the substance.

    <p>temporary</p> Signup and view all the answers

    Chemical changes produce one or more new ______ by altering the composition of the original substance.

    <p>substances</p> Signup and view all the answers

    Irreversible changes cannot be reversed by changing ______.

    <p>conditions</p> Signup and view all the answers

    Melting of ice is an example of a ______ change.

    <p>reversible</p> Signup and view all the answers

    Changes that occur at regular intervals are referred to as ______ changes.

    <p>periodic</p> Signup and view all the answers

    Desirable changes produce ______ results and can be induced by man or nature.

    <p>useful</p> Signup and view all the answers

    A seed growing into a tree is classified as a ______ change.

    <p>slow</p> Signup and view all the answers

    An example of an undesirable change is the ______ of glass.

    <p>breaking</p> Signup and view all the answers

    The burning of magnesium is a temporary change.

    <p>False</p> Signup and view all the answers

    During a chemical change, new substances are formed.

    <p>True</p> Signup and view all the answers

    A physical change is characterized by the formation of new products.

    <p>False</p> Signup and view all the answers

    In a chemical change, the mass of the substance remains unchanged despite the addition or removal of matter.

    <p>True</p> Signup and view all the answers

    Chemical changes can be reversed by simply reversing the conditions.

    <p>False</p> Signup and view all the answers

    Physical changes are temporary and easily reversible.

    <p>True</p> Signup and view all the answers

    Chemical changes result in the formation of new substances and are often temporary.

    <p>False</p> Signup and view all the answers

    Burning of magnesium is an example of a reversible change.

    <p>False</p> Signup and view all the answers

    Melting of ice is classified as an irreversible change.

    <p>False</p> Signup and view all the answers

    Chemical changes are characterized by the original substance losing its identity.

    <p>True</p> Signup and view all the answers

    Periodic changes occur randomly and do not have regular intervals.

    <p>False</p> Signup and view all the answers

    A seed growing into a tree is an example of a fast change.

    <p>False</p> Signup and view all the answers

    Desirable changes produce useful results and can be caused by human actions or natural processes.

    <p>True</p> Signup and view all the answers

    The freezing of water is considered an irreversible change.

    <p>False</p> Signup and view all the answers

    A chemical change is characterized by the formation of one or more new substances.

    <p>True</p> Signup and view all the answers

    A chemical change is characterized by the formation of new substances and altered composition of molecules.

    <p>True</p> Signup and view all the answers

    The change of seasons is an example of a periodic change.

    <p>True</p> Signup and view all the answers

    During a physical change, the substance undergoes a permanent alteration in its properties.

    <p>False</p> Signup and view all the answers

    Irreversible changes can always be reversed by changing conditions.

    <p>False</p> Signup and view all the answers

    The burning of magnesium results in an irreversible change that cannot be reversed by altering conditions.

    <p>True</p> Signup and view all the answers

    The melting of ice results in a permanent change of state.

    <p>False</p> Signup and view all the answers

    A physical change will always involve a change in mass of the substance undergoing that change.

    <p>False</p> Signup and view all the answers

    Desirable changes result in useful outcomes and are beneficial.

    <p>True</p> Signup and view all the answers

    A seed growing into a tree occurs very quickly and is classified as a fast change.

    <p>False</p> Signup and view all the answers

    Chemical changes are typically accompanied by an observable evolution or absorption of heat.

    <p>True</p> Signup and view all the answers

    Non-periodic changes occur at irregular intervals, often over long durations.

    <p>True</p> Signup and view all the answers

    What type of change involves the formation of new substances?

    <p>Chemical change.</p> Signup and view all the answers

    Give an example of a reversible physical change.

    <p>Melting of ice.</p> Signup and view all the answers

    What distinguishes irreversible changes from reversible changes?

    <p>Irreversible changes cannot be reversed by changing conditions.</p> Signup and view all the answers

    What is a characteristic of physical changes?

    <p>They are temporary and easily reversible.</p> Signup and view all the answers

    How are fast changes defined?

    <p>Fast changes occur quickly, often in seconds.</p> Signup and view all the answers

    What is an example of a desirable change?

    <p>Making of glass.</p> Signup and view all the answers

    Describe a periodic change with an example.

    <p>Periodic changes occur at regular intervals, like the change of seasons.</p> Signup and view all the answers

    What happens to the identity of a substance during a chemical change?

    <p>The substance loses its identity.</p> Signup and view all the answers

    Is the change resulting from burning magnesium considered permanent or temporary?

    <p>Permanent</p> Signup and view all the answers

    Does a chemical change like burning magnesium result in the formation of new substances?

    <p>Yes, magnesium oxide is formed.</p> Signup and view all the answers

    Can the change caused by burning magnesium be reversed by changing conditions?

    <p>No, it is irreversible.</p> Signup and view all the answers

    During a physical change, how does the composition of the molecules change?

    <p>The composition remains unchanged.</p> Signup and view all the answers

    What characterizes the mass of a substance during a physical change?

    <p>The mass remains unchanged.</p> Signup and view all the answers

    How do chemical changes differ from physical changes in terms of composition?

    <p>Chemical changes involve an altered composition of molecules, while physical changes maintain the original composition.</p> Signup and view all the answers

    Why is the change that occurs during the burning of magnesium considered irreversible?

    <p>The burning of magnesium leads to the formation of magnesium oxide, which cannot be easily recovered back to magnesium.</p> Signup and view all the answers

    What is the significance of heat evolution or absorption during a chemical change?

    <p>The evolution or absorption of heat indicates that a chemical reaction is occurring, which often leads to changes in molecular structure.</p> Signup and view all the answers

    In what way does the mass of substances change during a chemical change?

    <p>While total mass remains conserved, the mass of individual components may change as substances are transformed during the reaction.</p> Signup and view all the answers

    What role does the concept of reversibility play in distinguishing between physical and chemical changes?

    <p>Physical changes are typically reversible, while chemical changes are irreversible due to the formation of new substances.</p> Signup and view all the answers

    What differentiates a physical change from a chemical change?

    <p>A physical change retains the substance's identity and properties while changing form or state, whereas a chemical change alters the substance's composition, creating new substances.</p> Signup and view all the answers

    Provide an example of a reversible change and explain why it is classified as such.

    <p>The melting of ice is a reversible change because the ice can return to its solid state by freezing.</p> Signup and view all the answers

    Why are chemical changes considered permanent?

    <p>Chemical changes are permanent because they result in the formation of new substances, which cannot revert to their original state easily.</p> Signup and view all the answers

    What distinguishes irreversible changes from reversible changes?

    <p>Irreversible changes cannot be reverted by changing conditions, such as the burning of magnesium, which results in new substances.</p> Signup and view all the answers

    Give an example of a periodic change and describe its characteristics.

    <p>The change of seasons is an example of a periodic change, characterized by occurring at regular intervals throughout the year.</p> Signup and view all the answers

    How do fast changes differ from slow changes, and provide an example of each?

    <p>Fast changes, such as the occurrence of lightning, happen quickly, while slow changes, like a seed growing into a tree, occur gradually over time.</p> Signup and view all the answers

    What are desirable changes, and can you provide an example?

    <p>Desirable changes are those that yield beneficial results, such as the making of glass, which is useful in many applications.</p> Signup and view all the answers

    Explain the significance of slow changes in nature with an example.

    <p>Slow changes, such as erosion, play a significant role in shaping landscapes and ecosystems over time.</p> Signup and view all the answers

    Study Notes

    Physical Changes

    • A physical change is temporary and easily reversible
    • The state of the substance changes without altering its fundamental nature
    • No new substance is formed
    • The composition and properties of the original substance are not altered
    • Examples include, melting ice, freezing water, cutting a piece of paper

    Chemical Changes

    • A chemical change is permanent and not easily reversible
    • One or more new substances are formed
    • The composition and properties of the original substance are altered
    • Examples include burning of magnesium, rusting of iron, burning of wood

    Reversible and Irreversible Changes

    • Reversible changes can be reversed by a change in conditions
    • Examples of reversible changes include melting of ice and freezing of water
    • Irreversible changes cannot be reversed by a change in conditions
    • Examples of irreversible changes include burning of magnesium, cooking an egg

    Slow and Fast Changes

    • Slow Changes occur very slowly over days or years
    • Examples of slow changes include a seed growing into a tree
    • Fast changes occur very rapidly, in seconds
    • Examples of fast changes include the occurrence of lightning

    Periodic and Non-Periodic Changes

    • Periodic changes occur periodically at regular intervals
    • Examples of periodic changes include the change of seasons
    • Non-periodic changes do not occur periodically
    • Examples of non-periodic changes include the change of weather

    Desirable and Undesirable Changes

    • Desirable changes produce useful results and are brought about by man or nature
    • Examples of desirable changes include the making of glass
    • Undesirable changes produce useless results and are brought about by man or nature
    • Examples of undesirable changes include breaking of glass

    Physical Changes

    • A physical change alters the form or state of a substance without changing its composition.
    • The substance retains its identity.
    • Physical changes are temporary and easily reversible.
    • No new substance is formed during a physical change.
    • The composition and properties of the original substance remain unaltered.
    • Examples include melting of ice, freezing of water, boiling of water, and sublimation of iodine.

    Chemical Changes

    • A chemical change involves the formation of one or more new substances by altering the composition of the original substance.
    • The substance loses its identity and produces one or more new substances.
    • Chemical changes are permanent and not easily reversible.
    • A new substance is formed during a chemical change.
    • The composition and properties of the original substance are altered.
    • Examples include burning of magnesium, rusting of iron, burning of wood, and cooking of food.

    Differences Between Physical and Chemical Changes:

    • Physical Changes*
    • Composition of substance is unaltered.
    • No new products formed.
    • Temporary change, reversible by reversing conditions.
    • No change in mass of the substance undergoing a change.
    • Not accompanied by marked evolution or absorption of heat.
    • Chemical Changes*
    • Composition of substance is altered.
    • New products are formed.
    • Permanent change, not reversed by reversing conditions.
    • Change in mass of the substance undergoing a change.
    • Accompanied by evolution or absorption of heat, and sometimes emission of light.

    Physical and Chemical Changes

    • Physical changes involve a change in the form or state of a substance without altering its fundamental composition.
      • These changes are temporary and easily reversible.
      • No new substances are formed.
      • The original substance's composition and properties remain unchanged.
      • Examples: melting of ice, freezing of water, boiling water.
    • Chemical changes involve a change in the composition of a substance, resulting in the formation of one or more new substances with different properties.
      • These changes are permanent and not easily reversible.
      • New substances are formed.
      • The original substance's composition and properties are altered.
      • Examples: burning of magnesium, rusting of iron, cooking an egg.

    Reversible and Irreversible Changes

    • Reversible changes can be reversed by changing the conditions.
      • Example: melting of ice and freezing of water.
    • Irreversible changes cannot be reversed by changing the conditions.
      • Example: burning of magnesium.

    Slow and Fast Changes

    • Slow Changes occur gradually over a longer period.
      • Example: a seed growing into a tree.
    • Fast Changes occur quickly.
      • Example: the occurrence of lightning.

    Periodic and Non-periodic Changes

    • Periodic Changes occur at regular intervals.
      • Example: the change of seasons.
    • Non-periodic Changes do not occur at regular intervals.
      • Example: changes in weather.

    Desirable and Undesirable Changes

    • Desirable Changes produce useful results and can be brought about by humans or nature.
      • Example: making of glass.
    • Undesirable Changes produce useless results and can be brought about by humans or nature.
      • Example: breaking of glass.

    Physical Changes

    • A physical change refers to a change in the form or state of a substance without altering its fundamental chemical composition.
    • The substance retains its identity, and the change is temporary and easily reversible.
    • Examples of physical changes include melting ice, freezing water, and boiling water.

    Chemical Changes

    • A chemical change involves the formation of new substances with different properties from the original substance. The original substance loses its identity.
    • The change is permanent, not easily reversible, and involves a change in the composition of the substance.
    • Examples include burning magnesium, rusting of iron, and cooking an egg.

    Reversible and Irreversible Changes

    • Reversible changes can be reversed by changing the conditions, such as melting ice and freezing water.
    • Irreversible changes cannot be reversed by changing the conditions, such as burning magnesium.

    Slow and Fast Changes

    • Slow changes occur over a longer period, such as a seed growing into a tree.
    • Fast changes occur rapidly, such as the occurrence of lightning.

    Periodic and Non-periodic Changes

    • Periodic changes occur at regular intervals, such as the change of seasons.
    • Non-periodic changes do not occur at regular intervals, such as the change of weather.

    Desirable and Undesirable Changes

    • Desirable changes produce useful results, such as making glass.
    • Undesirable changes produce useless results, such as breaking glass.

    Comparing Physical and Chemical Changes

    • Physical Changes:
      • No change in the composition of the molecules
      • No new substances are formed
      • Temporary change that can be reversed
      • No change in the mass of the substance
      • Not accompanied by significant heat evolution or absorption
    • Chemical Changes:
      • Change in the composition of the molecules
      • New substances are formed
      • Permanent change that cannot be reversed
      • Change in the mass of the substance
      • Often accompanied by heat evolution or absorption, and sometimes emission of light

    Physical and Chemical Changes

    • Physical changes are temporary and easily reversible.
    • Physical changes result in a change of state without altering the fundamental nature of the substance.
    • Examples include melting of ice and freezing of water.

    Chemical Changes

    • Chemical changes are permanent and not easily reversible.
    • Chemical changes result in the formation of new substances.
    • Examples include burning of magnesium.

    Reversible and Irreversible Changes

    • Reversible changes can be reversed by changing conditions.
    • Examples include melting of ice and freezing of water.
    • Irreversible changes cannot be reversed by changing conditions.
    • Examples include burning of magnesium.

    Slow and Fast Changes

    • Slow changes occur slowly over days or years.
    • Examples include a seed growing into a tree.
    • Fast changes occur rapidly in seconds.
    • Examples include lightning.

    Periodic and Non-Periodic Changes

    • Periodic changes occur at regular intervals.
    • Examples include the change of seasons.
    • Non-periodic changes do not occur periodically.
    • Examples include the change of weather.

    Desirable and Undesirable Changes

    • Desirable changes produce useful results and are brought about by man or nature.
    • Examples include making glass.
    • Undesirable changes produce useless results and are brought about by man or nature.
    • Examples include breaking glass.

    Definitions

    • Physical Change: A change where the substance retains its identity and changes in form or state without altering its composition.
    • Chemical Change: A change where the substance loses its identity and produces one or more new substances by changing its composition.

    Examples

    • Physical Change: Melting of ice.
    • Chemical Change: Burning of magnesium.

    Comparison of Physical and Chemical Changes

    • Physical Changes:
      • The composition of the molecules of the substance remains unaltered.
      • No new products are formed.
      • The change is temporary and can be reversed by reversing conditions.
      • There is no change in the mass of the substance undergoing a physical change.
      • The change is not accompanied by a marked evolution or absorption of heat.
    • Chemical Changes:
      • The composition of the molecules of the substance is altered.
      • New products are formed.
      • The change is permanent and cannot be reversed by reversing conditions.
      • There is a change in the mass of the substance undergoing a chemical change.
      • The change is accompanied by the evolution or absorption of heat and sometimes the emission of light.

    Physical Changes

    • A physical change alters the form or state of a substance without changing its composition.
    • The substance retains its identity and properties remain the same.
    • Physical changes are temporary and easily reversible.
    • Examples of physical changes include melting ice, freezing water, boiling water, crushing a rock, and dissolving sugar in water.

    Chemical Changes

    • A chemical change involves the formation of one or more new substances with different properties than the original.
    • These changes are permanent and not easily reversible.
    • Examples of chemical changes include burning wood, rusting iron, cooking food, and baking a cake.

    Reversible & Irreversible Changes

    • Reversible Changes: These are changes that can be reversed by changing conditions.
      • Example: Melting ice (solid to liquid) can be reversed by freezing the water (liquid to solid).
    • Irreversible Changes: These are changes that cannot be reversed by simply changing external conditions.
      • Example: Burning a piece of paper cannot be reversed to get back the original paper.

    Slow and Fast Changes

    • Slow Changes: These changes occur gradually over time.
      • Example: A seed growing into a tree.
    • Fast Changes: These changes occur rapidly.
      • Example: The occurrence of lightning.

    Periodic and Non-Periodic Changes

    • Periodic Changes: These changes occur at regular intervals.
      • Example: The change of seasons.
    • Non-Periodic Changes: These changes do not occur at regular intervals.
      • Example: The change of weather.

    Desirable and Undesirable Changes

    • Desirable Changes: These changes produce useful results and can be brought about by humans or nature.
      • Example: Making glass.
    • Undesirable Changes: These changes produce unwanted or harmful results and can be brought about by humans or nature.
      • Example: Breaking glass.

    Physical Changes

    • A physical change affects the form or state of a substance but not its fundamental nature.

    • Key characteristics of physical changes include:

      • Temporary and easily reversible
      • No new substance is formed
      • The original substance's composition and properties remain unaltered

    • Examples of physical changes include:

      • Melting of ice
      • Freezing of water
      • Boiling of water
      • Condensation of water vapor

    Chemical Changes

    • A chemical change involves a substance losing its identity and producing one or more new substances.

    • Key characteristics of chemical changes include:

      • Permanent and not easily reversible
      • A new substance is formed
      • The original substance's composition and properties are altered

    • Examples of chemical changes include:

      • Burning of magnesium
      • Rusting of iron
      • Baking of bread

    Reversible and Irreversible Changes

    • A reversible change can be reversed by changing the conditions.
      • Melting of ice and freezing of water are examples of reversible changes.
    • An irreversible change cannot be reversed by changing conditions.
      • Burning of magnesium is an example of an irreversible change.

    Slow and Fast Changes

    • Slow changes happen over a long period of time.
      • The growth of a seed into a tree is an example of a slow change.
    • Fast changes happen quickly.
      • The occurrence of lightning is an example of a fast change.

    Periodic and Non-Periodic Changes

    • Periodic changes occur at regular intervals.
      • The change of seasons is an example of a periodic change.
    • Non-periodic changes do not occur at regular intervals.
      • The change of weather is an example of a non-periodic change.

    Desirable and Undesirable Changes

    • Desirable changes produce useful results and are brought about by humans or nature.
      • The making of glass is an example of a desirable change.
    • Undesirable changes produce useless results and are brought about by humans or nature.
      • The breaking of glass is an example of an undesirable change.

    Physical & Chemical Changes

    • Physical change is temporary and can be reversed.
    • The substance retains its identity and properties, changing only in form or state.
    • Chemical change is permanent and irreversible.
    • The substance loses its identity and forms one or more new substances, altering its composition and properties.

    Examples of Physical Changes

    • Melting of ice: Water changes from a solid to a liquid, but its chemical composition (H2O) remains the same.
    • Freezing of water: This is the reverse of melting, and the composition remains unchanged.

    Examples of Chemical Changes

    • Burning of magnesium:
      • Magnesium ribbon reacts with oxygen in the air, forming magnesium oxide, a new substance with different properties. This change is irreversible and involves a change in composition.

    Comparison of Physical and Chemical Changes

    • Physical Changes:
      • No new substances are formed.
      • The change is temporary and can be easily reversed.
      • No change in the mass of the substance occurs.
      • No significant heat evolution or absorption is evident during a physical change.
    • Chemical Changes:
      • New substances are formed.
      • The change is permanent and irreversible.
      • The mass of the substance can change due to the addition or removal of matter, but the total mass remains constant.
      • Heat evolution or absorption, sometimes with light emission, are common during a chemical change.

    Physical Changes

    • A physical change is a temporary, easily reversible alteration in a substance’s form or state, without changing its composition or properties
    • The chemical identity of the substance remains the same, and no new substances are formed
    • Examples of Physical Changes:
      • Melting of ice
      • Freezing of water
      • Boiling of water
      • Condensation of steam
      • Sublimation of iodine
      • Dissolution of sugar in water
      • Evaporation of water
      • Cutting paper

    Chemical Changes

    • A chemical change is a permanent, irreversible alteration in a substance’s composition, resulting in one or more new substances with different properties
    • A new substance is formed with a new chemical formula and altered properties
    • Examples of Chemical Changes:
      • Burning of magnesium
      • Rusting of iron
      • Digestion of food
      • Cooking an egg
      • Souring of milk
      • Burning of wood
      • Photosynthesis
      • Fermentation

    Reversible and Irreversible Changes

    • Reversible changes can be reversed by altering conditions, like melting ice and freezing water
    • Irreversible changes cannot be reversed by simple means, like burning a piece of paper
    • Examples of Irreversible Changes:
      • Burning of paper
      • Cooking of an egg
      • Rusting of iron
      • Digesting food

    Slow and Fast Changes

    • Slow changes are temporary changes that occur gradually over a long period of time, examples include the growth of a tree, the rusting of iron
    • Fast Changes occur rapidly, examples include the explosion of fireworks and the occurrence of lightening

    Periodic and Non-Periodic Changes

    • Periodic changes occur repeatedly at regular intervals, like the change of seasons
    • Non-periodic changes occur irregularly, like the change of weather

    Desirable and Undesirable Changes

    • Desirable changes are beneficial and useful, such as the making of glass
    • Undesirable changes are harmful and unwanted, like the breaking of glass

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    Description

    This quiz explores the concepts of physical and chemical changes in matter. Learn the differences between reversible and irreversible changes, as well as the various examples of each type. Test your knowledge and understanding of how substances can change their state and composition.

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