C.B.S.E Solution

Chapter 1 – Some Basic Concepts of Chemistry

Some Basic Concepts of Chemistry Question 1.Calculate the molecular mass of the following :(i) H2o(ii) CO2(iii) CH4 Solution:(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 + 4 × 1 = 16 u Question 2.Calculate the mass percent of […]

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Chapter 14 – Mathematical Reasoning (Ex – 14.5)

Mathematical Reasoning (Ex – 14.5) Question 1.Show that the statementp: “If x is a real number such that x3 + 4x = 0, then x is 0″ is true by(i) direct method,(ii) method of contradiction,(iii) method of contrapositive. Solution:The given compound statement is of the form “if p then q”p: x ϵ R such that x3 + 4x = 0q:

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Chapter 14 – Mathematical Reasoning (Ex – 14.4)

Mathematical Reasoning (Ex – 14.4) Question 1.Rewrite the following statement with “if-then” in five different ways conveying the same meaning. If a natural number is odd, then its square is also odd. Solution:(i) A natural number is odd implies that its square is odd.(ii) A natural number is odd only if its square is odd.(iii) For a natural

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Chapter 14 – Mathematical Reasoning (Ex – 14.3)

Mathematical Reasoning (Ex – 14.3) Question 1.For each of the following compound statements first, identify the connecting words and then break it into component statements.(i) All rational numbers are real and all real numbers are not complex.(ii) Square of an integer is positive or negative.(iii) The sand heats up quickly in the Sun and does not cool down

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