Chapter 10 The s-Block Elements
Chapter 10 The s-Block Elements Question 1. What are the common physical and chemical features of alkali metals ? Answer: Property Li Na K Rb Cs Fr Atomic number 3 11 19 37 55 87 Atomic mass (g mol-1) 6-94 22-99 39-10 85-47 132-91 (223) Atomic (Metallic) radius (pm) 152 186 227 248 265 — […]
Chapter 9 Hydrogen
Chapter 9 Hydrogen Question 1. Justify the position of hydrogen in the periodic table on the basis of its electronic configuration. Answer:Position of Hydrogen in the Periodic Table In the periodic table, hydrogen has been placed at the top of the alkali metals in group 1 although it is not a member of the group. […]
Chapter 8 Redox Reactions
Chapter 8 Redox Reactions Question 1. Assign oxidation numbers to the underlined elements in each of the following species ; (a) NaH2PO4 (b) NaHSO4 (c) H4P2O7 (d) K2MnO4 (e) CaO2 (f) NaBH4 (g) H2S2O7 (h) KAl(SO4)2.12H2O Answer: Question 2. What are the oxidation numbers of the underlined elements in each of the following and how […]
Chapter 7 Equilibrium
Chapter 7 Equilibrium Question 1. A liquid is in equilibrium with its vapours in a sealed container at a fixed temperature. The volume of the container is suddenly increased, (i) What is the initial effect of the change on the vapour pressure ? (ii) How do the rates of evaporation and condensation change initially ? […]
Chapter 6 Thermodynamics
Chapter 6 Thermodynamics Question 1. Choose the correct answer. A thermodynamic state function is a quantity (i) used to determine heat changes (ii) whose value is independent of path (iii) used to determine pressure volume work (iv) whose value depends on temperature only. Answer: (ii) whose value is independent of path Question 2. For the process […]
Chapter 5 States of Matter Gases and Liquids
Chapter 5 States of Matter Gases and Liquids Question 1. What will be the minimum pressure required to compress 500 dm3 of air at 1 bar to 200 dm3 at 30° C ? Answer: From the given data : P1 = 1 bar P2 = ? V1 = 500 dm3 V2 = 200 dm3 P1V1 = V1P2 or P2 = P1V1V2 Question 2. A vessel of […]
Chapter 4 Chemical Bonding and Molecular Structure
Chapter 4 Chemical Bonding and Molecular Structure Question 1. Explain the formation of chemical bond. Answer: Inert gases or noble gas elements are present in group 18 also called zero group. This means that their valency is zero or their atoms can exist independently of their own. Let us have a close look at their […]
Chapter 3 Classification of Elements and Periodicity in Properties
Chapter 3 Classification of Elements and Periodicity in Properties Question 1. What is the basic theme of organisation in periodic table ? Answer: The basic theme of organisation in periodic table is to group the elements with same characteristics (physical and chemical) together so that it may become rather easy to follow these characteristics. Since […]
Chapter 2 Structure of Atom
Chapter 2 Structure of Atom Question 1. (i) Calculate the number of electrons which will together weigh one gram. (ii) Calculate the mass and charge of one mole of electrons. Answer: (i) Mass of an electron = 9.1 × 10-28 g 9.1 × 10-28 g is the mass of = 1 electron (ii) One mole of electrons = 6.022 […]
Chapter 1 Some Basic Concepts of Chemistry
Chapter 1 Some Basic Concepts of Chemistry Question 1. Calculate the molecular mass of the following : (i) H2O (ii) CO2 (iii) CH4 Answer: (i) Molecular mass of H2O : 2 × 1 + 1 × 16 = 18u (ii) Molecular mass of CO2 : 1 × 12 + 2× 16 = 44 u (iii) Molecular mass of CH4 : 12 […]