Basic Chemistry Questions and Answers for Class 9 and 10 Students

Basic Chemistry Questions and Answers: Introduction

Chemistry is a fascinating subject that forms the foundation for understanding the world around us. For students in Class 9 and 10 (SSC, CBSE, and ICSE boards), mastering basic chemistry concepts is crucial for excelling in exams and building a strong base for higher studies. This article provides a comprehensive list of 100 one-liner Basic Chemistry Questions and Answers designed to help students revise key topics like matter, atoms, molecules, chemical reactions, and more. These questions are concise, exam-focused, and aligned with the latest syllabi, ensuring effective preparation.

Basic Chemistry Questions and Answers

  1. What is matter?
    Matter is anything that has mass and occupies space.
  2. What are the three states of matter?
    Solid, liquid, and gas.
  3. What is an atom?
    An atom is the smallest unit of an element that retains its chemical properties.
  4. What is a molecule?
    A molecule is a group of atoms bonded together, forming the smallest unit of a compound.
  5. What is an element?
    An element is a pure substance made of one type of atom.
  6. What is a compound?
    A compound is a substance formed by the chemical combination of two or more elements.
  7. What is the atomic number?
    The atomic number is the number of protons in an atom’s nucleus.
  8. What is the mass number?
    The mass number is the total number of protons and neutrons in an atom’s nucleus.
  9. What is a proton?
    A proton is a positively charged particle found in the nucleus of an atom.
  10. What is a neutron?
    A neutron is a neutral particle found in the nucleus of an atom.
  11. What is an electron?
    An electron is a negatively charged particle orbiting the nucleus of an atom.
  12. What is the nucleus of an atom?
    The nucleus is the dense, central part of an atom containing protons and neutrons.
  13. What is a chemical reaction?
    A chemical reaction is a process where substances (reactants) transform into new substances (products).
  14. What is a physical change?
    A physical change alters the form of a substance without changing its chemical composition.
  15. What is a chemical change?
    A chemical change results in the formation of new substances with different properties.
  16. What is the law of conservation of mass?
    The law states that mass is neither created nor destroyed in a chemical reaction.
  17. What is a mixture?
    A mixture is a combination of two or more substances that are not chemically bonded.
  18. What is a homogeneous mixture?
    A homogeneous mixture has a uniform composition throughout, like saltwater.
  19. What is a heterogeneous mixture?
    A heterogeneous mixture has a non-uniform composition, like sand and water.
  20. What is a solution?
    A solution is a homogeneous mixture of a solute dissolved in a solvent.
  21. What is a solute?
    A solute is the substance that dissolves in a solvent to form a solution.
  22. What is a solvent?
    A solvent is the substance that dissolves a solute to form a solution.
  23. What is distillation?
    Distillation is a process to separate liquids based on differences in their boiling points.
  24. What is filtration?
    Filtration is a method to separate solids from liquids using a filter.
  25. What is evaporation?
    Evaporation is the process of a liquid turning into a gas at its surface.
  26. What is sublimation?
    Sublimation is the direct transition of a substance from solid to gas without becoming liquid.
  27. What is the boiling point?
    The boiling point is the temperature at which a liquid turns into a gas.
  28. What is the melting point?
    The melting point is the temperature at which a solid turns into a liquid.
  29. What is the freezing point?
    The freezing point is the temperature at which a liquid turns into a solid.
  30. What is a pure substance?
    A pure substance has a fixed composition and definite properties, like water or oxygen.
  31. What is an isotope?
    Isotopes are atoms of the same element with different numbers of neutrons.
  32. What is a valence electron?
    A valence electron is an electron in the outermost shell of an atom.
  33. What is a chemical bond?
    A chemical bond is a force that holds atoms together in a molecule or compound.
  34. What is an ionic bond?
    An ionic bond is a bond formed by the transfer of electrons between atoms.
  35. What is a covalent bond?
    A covalent bond is a bond formed by the sharing of electrons between atoms.
  36. What is a metallic bond?
    A metallic bond is a bond between metal atoms, involving delocalized electrons.
  37. What is an acid?
    An acid is a substance that donates protons or releases H⁺ ions in a solution.
  38. What is a base?
    A base is a substance that accepts protons or releases OH⁻ ions in a solution.
  39. What is a pH scale?
    The pH scale measures the acidity or alkalinity of a solution, ranging from 0 to 14.
  40. What is a neutral solution?
    A neutral solution has a pH of 7, neither acidic nor basic.
  41. What is a catalyst?
    A catalyst is a substance that speeds up a chemical reaction without being consumed.
  42. What is an exothermic reaction?
    An exothermic reaction releases heat energy to the surroundings.
  43. What is an endothermic reaction?
    An endothermic reaction absorbs heat energy from the surroundings.
  44. What is a balanced chemical equation?
    A balanced chemical equation has an equal number of atoms for each element on both sides.
  45. What is the periodic table?
    The periodic table is a chart organizing elements by atomic number and properties.
  46. What is a metal?
    A metal is an element that is shiny, conducts heat and electricity, and is malleable.
  47. What is a non-metal?
    A non-metal is an element that is dull, poor conductor, and brittle.
  48. What is a metalloid?
    A metalloid is an element with properties between metals and non-metals.
  49. What is a noble gas?
    A noble gas is an element in Group 18 of the periodic table, chemically inert.
  50. What is a mole?
    A mole is a unit measuring the amount of substance, containing 6.022 × 10²³ particles.
  51. What is Avogadro’s number?
    Avogadro’s number is 6.022 × 10²³, the number of particles in one mole.
  52. What is molar mass?
    Molar mass is the mass of one mole of a substance, measured in grams per mole.
  53. What is a chemical formula?
    A chemical formula shows the types and numbers of atoms in a compound.
  54. What is an empirical formula?
    An empirical formula shows the simplest ratio of atoms in a compound.
  55. What is a molecular formula?
    A molecular formula shows the actual number of atoms in a molecule.
  56. What is a suspension?
    A suspension is a heterogeneous mixture where particles settle over time.
  57. What is a colloid?
    A colloid is a mixture where particles are dispersed but do not settle, like milk.
  58. What is the Tyndall effect?
    The Tyndall effect is the scattering of light by particles in a colloid or suspension.
  59. What is an alloy?
    An alloy is a mixture of two or more metals, like brass or steel.
  60. What is corrosion?
    Corrosion is the gradual destruction of metals by chemical reactions, like rusting.
  61. What is rust?
    Rust is iron oxide formed when iron reacts with oxygen and moisture.
  62. What is a redox reaction?
    A redox reaction involves both reduction and oxidation processes.
  63. What is oxidation?
    Oxidation is the loss of electrons or gain of oxygen in a reaction.
  64. What is reduction?
    Reduction is the gain of electrons or loss of oxygen in a reaction.
  65. What is a precipitate?
    A precipitate is an insoluble solid formed during a chemical reaction.
  66. What is electrolysis?
    Electrolysis is the process of using electricity to drive a chemical reaction.
  67. What is an electrolyte?
    An electrolyte is a substance that conducts electricity when dissolved in water.
  68. What is a non-electrolyte?
    A non-electrolyte is a substance that does not conduct electricity in solution.
  69. What is a hydrocarbon?
    A hydrocarbon is a compound made of only carbon and hydrogen atoms.
  70. What is an alkane?
    An alkane is a hydrocarbon with single bonds between carbon atoms.
  71. What is an alkene?
    An alkene is a hydrocarbon with at least one double bond between carbon atoms.
  72. What is an alkyne?
    An alkyne is a hydrocarbon with at least one triple bond between carbon atoms.
  73. What is combustion?
    Combustion is a chemical reaction where a substance reacts rapidly with oxygen, producing heat and light.
  74. What is a greenhouse gas?
    A greenhouse gas traps heat in the Earth’s atmosphere, like carbon dioxide.
  75. What is the law of definite proportions?
    The law states that a compound always contains the same elements in fixed proportions.
  76. What is Dalton’s atomic theory?
    Dalton’s theory states that matter is made of indivisible atoms, and atoms of the same element are identical.
  77. What is a cation?
    A cation is a positively charged ion formed by losing electrons.
  78. What is an anion?
    An anion is a negatively charged ion formed by gaining electrons.
  79. What is a radical?
    A radical is a group of atoms that behaves as a single unit in a chemical reaction.
  80. What is valency?
    Valency is the combining capacity of an element, determined by its electrons.
  81. What is a molecular mass?
    Molecular mass is the sum of the atomic masses of all atoms in a molecule.
  82. What is an ion?
    An ion is an atom or molecule with a net electric charge due to gain or loss of electrons.
  83. What is a salt?
    A salt is a compound formed by the neutralization of an acid and a base.
  84. What is a neutralization reaction?
    A neutralization reaction is a reaction between an acid and a base to form salt and water.
  85. What is a polymer?
    A polymer is a large molecule made of repeating smaller units called monomers.
  86. What is a monomer?
    A monomer is a small molecule that can join to form a polymer.
  87. What is Boyle’s law?
    Boyle’s law states that the volume of a gas is inversely proportional to its pressure at constant temperature.
  88. What is Charles’ law?
    Charles’ law states that the volume of a gas is directly proportional to its temperature at constant pressure.
  89. What is Gay-Lussac’s law?
    Gay-Lussac’s law states that the pressure of a gas is directly proportional to its temperature at constant volume.
  90. What is diffusion?
    Diffusion is the movement of particles from a region of higher concentration to lower concentration.
  91. What is osmosis?
    Osmosis is the movement of water molecules across a semi-permeable membrane from a region of lower solute concentration to higher.
  92. What is a semi-permeable membrane?
    A semi-permeable membrane allows certain molecules, like water, to pass through but blocks others.
  93. What is a saturated solution?
    A saturated solution contains the maximum amount of solute that can dissolve in a solvent at a given temperature.
  94. What is an unsaturated solution?
    An unsaturated solution can dissolve more solute at a given temperature.
  95. What is a supersaturated solution?
    A supersaturated solution contains more solute than it can normally hold at a given temperature.
  96. What is an indicator?
    An indicator is a substance that changes color to show the pH of a solution, like litmus.
  97. What is litmus paper?
    Litmus paper is a pH indicator that turns red in acidic solutions and blue in basic solutions.
  98. What is a universal indicator?
    A universal indicator shows a range of colors to indicate the pH of a solution.
  99. What is the reactivity series?
    The reactivity series is a list of metals arranged in order of decreasing reactivity.
  100. What is displacement reaction?
    A displacement reaction is a reaction where a more reactive element displaces a less reactive element from its compound.

This collection of Basic Chemistry Questions and Answers is a valuable resource for Class 9 and 10 students preparing for SSC, CBSE, and ICSE exams. By practicing these concise and syllabus-aligned questions, students can strengthen their understanding of fundamental chemistry concepts, improve problem-solving skills, and gain confidence for their exams. Regular revision with these questions will ensure a solid foundation for future studies in science.


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