Page 140 - Chemistry ICSE Class X

126 ICSE Chemistry – 10

ASSIGNMENT 2

Normal temperature and pressure, Standard temperature and pressure, Gay-Lussac’s law of
combining volumes, Avogadro’s law, Atomicity, Applications of Avogadro’s law

ϭ͘ tŚĂƚ ŝƐ ŵĞĂŶƚ ďLJ
;ĂͿ EŽƌŵĂů ƚĞŵƉĞƌĂƚƵƌĞ ĂŶĚ ƉƌĞƐƐƵƌĞ ;EdWͿ͍
;ďͿ ^ƚĂŶĚĂƌĚ ƚĞŵƉĞƌĂƚƵƌĞ ĂŶĚ ƉƌĞƐƐƵƌĞ ;^dWͿ͍
Ϯ͘ ;ĂͿ ^ƚĂƚĞ 'ĂLJͲ>ƵƐƐĂĐ͛Ɛ ůĂǁ ŽĨ ĐŽŵďŝŶŝŶŐ ǀŽůƵŵĞƐ͘
;ďͿ 'ŝǀĞ ĂŶ ĞdžĂŵƉůĞ ƚŽ ŝůůƵƐƚƌĂƚĞ ƚŚĞ ĂďŽǀĞ ůĂǁ͘
ϯ͘ ŵŝdžƚƵƌĞ ĐŽŶƚĂŝŶŝŶŐ ϲ ůŝƚƌĞƐ ŽĨ ŚLJĚƌŽŐĞŶ ĂŶĚ ϱ͘ϲ ůŝƚƌĞƐ ŽĨ ĐŚůŽƌŝŶĞ ŝƐ ĞdžƉůŽĚĞĚ͘ tŚĂƚ ǁŝůů ďĞ ƚŚĞ ĐŽŵƉŽƐŝƟŽŶ ;ďLJ ǀŽůƵŵĞͿ
ŽĨ ƚŚĞ ƌĞƐƵůƟŶŐ ŐĂƐĞŽƵƐ ŵŝdžƚƵƌĞ͍ [Ans. V;, ůͿ с ϭϭ͘Ϯ >͕ V;, Ϳ с Ϭ͘ϰ >]
Ϯ
ϰ͘ ϱϬϬ ŵ> ŽĨ ŶŝƚƌŝĐ ŽdžŝĚĞ ŝƐ ƌĞĂĐƚĞĚ ǁŝƚŚ ϯϬϬ ŵ> ŽĨ ŽdžLJŐĞŶ ƚŽ ĨŽƌŵ ŶŝƚƌŽŐĞŶ ĚŝŽdžŝĚĞ͘ tŚĂƚ ǁŽƵůĚ ďĞ ƚŚĞ ĐŽŵƉŽƐŝƟŽŶ ŽĨ ƚŚĞ
ƌĞĂĐƟŽŶ ŵŝdžƚƵƌĞ͍ [Ans. V;EK Ϳ с ϱϬϬ ŵ>͕ V;ƵŶƵƐĞĚ K Ϳ с ϱϬ ŵ>]
Ϯ
Ϯ
ϱ͘ ^ƚĂƚĞ ǀŽŐĂĚƌŽ͛Ɛ ůĂǁ͘
ϲ͘ tŚĂƚ ŝƐ ŵĞĂŶƚ ďLJ ǀŽŐĂĚƌŽ͛Ɛ ĐŽŶƐƚĂŶƚ͍ tŚĂƚ ŝƐ ŝƚƐ ǀĂůƵĞ͍
ϳ͘ ;ĂͿ tŚĂƚ ŝƐ ŵŽůĂƌ ǀŽůƵŵĞ͍
;ďͿ tŚĂƚ ŝƐ ƚŚĞ ŵŽůĂƌ ǀŽůƵŵĞ ŽĨ Ă ŐĂƐ ƵŶĚĞƌ EdW ĐŽŶĚŝƟŽŶƐ͍
ϴ͘ ;ĂͿ tŚĂƚ ŝƐ ƚŚĞ ĂƚŽŵŝĐŝƚLJ ŽĨ പപ;ŝͿ ƉŚŽƐƉŚŽƌƵƐ പപ;ŝŝͿ ŽdžLJŐĞŶ പപ;ŝŝŝͿ ƐƵůƉŚƵƌ͍
;ďͿ tƌŝƚĞ ƚŚĞ ŵĂƚŚĞŵĂƟĐĂů ĨŽƌŵƵůĂ ǁŚŝĐŚ ƌĞůĂƚĞƐ ǀĂƉŽƵƌ ĚĞŶƐŝƚLJ ŽĨ Ă ŐĂƐĞŽƵƐ ƐƵďƐƚĂŶĐĞ ƚŽ ŝƚƐ ŵŽůĞĐƵůĂƌ ŵĂƐƐ͘
ϵ͘ hŶĚĞƌ ƐŝŵŝůĂƌ ĐŽŶĚŝƟŽŶƐ ŽĨ ƚĞŵƉĞƌĂƚƵƌĞ ĂŶĚ ƉƌĞƐƐƵƌĞ͕ Ϯ > ŽĨ ĐĂƌďŽŶ ĚŝŽdžŝĚĞ͕ ϯ > ŽĨ ĐŚůŽƌŝŶĞ͕ ϱ > ŽĨ ŚLJĚƌŽŐĞŶ͕ ϰ > ŽĨ
ŶŝƚƌŽŐĞŶ ĂŶĚ ϭ > ŽĨ ƐƵůƉŚƵƌ ĚŝŽdžŝĚĞ ĂƌĞ ƚĂŬĞŶ͘ tŚŝĐŚ ŽĨ ƚŚĞƐĞ ƐĂŵƉůĞƐ ǁŝůů ŚĂǀĞ
;ĂͿ ƚŚĞ ŵĂdžŝŵƵŵ ŶƵŵďĞƌ ŽĨ ŵŽůĞĐƵůĞƐ
;ďͿ ƚŚĞ ůĞĂƐƚ ŶƵŵďĞƌ ŽĨ ŵŽůĞĐƵůĞƐ͘
ϭϬ͘ ϱϬϬ ŵ> ŽĨ ŚLJĚƌŽŐĞŶ ĐŽŶƚĂŝŶƐ n ŵŽůĞĐƵůĞƐ͘ ,Žǁ ŵĂŶLJ ŵŽůĞĐƵůĞƐ ŽĨ ŽdžLJŐĞŶ ǁŝůů ďĞ ƉƌĞƐĞŶƚ ŝŶ ϮϱϬ ŵ> ŽĨ ŽdžLJŐĞŶ ƵŶĚĞƌ
ƐŝŵŝůĂƌ ĐŽŶĚŝƟŽŶƐ ŽĨ ƚĞŵƉĞƌĂƚƵƌĞ ĂŶĚ ƉƌĞƐƐƵƌĞ͍ [Ans. nͬϮ]

Atomic Mass and Relative Atomic Mass

Atom is the smallest particle which takes part in a chemical reaction. A
molecule is the smallest unit of any substance which can exist independently,
and shows all the properties of that substance. Each molecule is a group of
chemically bonded atoms.
Each atom or a molecule has its own characteristic mass. So, the atomic
and molecular masses may be expressed in any unit of mass, i.e., in gram,
kilograms, etc. But the actual mass of a single atom is very small. An atom
of hydrogen (the lightest atom) is 0.000 000 000 000 000 000 000 000 001
673 kg (1.673 × 10 –27 kg). It is not possible to measure such small masses
even with the help of the most sensitive balance. Such small numbers are
not very convenient to write also.
IUPAC accepted in 1961 the atomic mass unit scale to be used for
expressing atomic and molecular masses. In this scale of atomic masses,
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the C isotope has been assigned an atomic mass of 12.000000 atomic mass
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units.
What is the atomic mass unit
Atomic masses are very small. To express atomic masses, a unit called
dŚĞ ĂƚŽŵŝĐ ŵĂƐƐ ƵŶŝƚ ŝƐ ĂďďƌĞǀŝĂƚĞĚ atomic mass unit (abbreviation, amu; symbol, u) is commonly used. The
ĂƐ amu͕ ĂŶĚ ĚĞŶŽƚĞĚ ďLJ ƚŚĞ ƐLJŵďŽů
Ƶ͕ Žƌ ŵ ͘ tĞ ĂƌĞ ƵƐŝŶŐ ƚŚĞ ƐLJŵďŽů Ƶ CVQOKE OCUU WPKV KU FGſPGF CU HQNNQYU
u
12
1
ĨŽƌ ĂƚŽŵŝĐ ŵĂƐƐ ƵŶŝƚ ŝŶ ƚŚŝƐ Ŭ͘ The mass equal to th of the mass of a C atom is called one atomic
6
12
mass unit.