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5 months ago
New question posted
5 months agoNew answer posted
5 months agoContributor-Level 10
(i) One mole of methane (CH4) has = 6.022 * 1023 molecules
No. of electrons present in one molecule of CH4 = 6 + (4 x 1) = 10
No. of electrons present in 6.022 * 1023 molecules of CH4 = 6.022 * 1023 * 10
= 6.022 * 1024 electrons
(ii) (a)
Calculation of total number of carbon atoms
Gram atomic mass of carbon (C-14) = 14 g = 14 * 103 mg
14 g or 14 * 103 mg of carbon (C-14) has 6.022 * 1023 ato
New answer posted
5 months agoContributor-Level 10
43. A process which can take place of its own or initiate under some conditions. For example: Common salt dissolves in water of its own.
New answer posted
5 months agoContributor-Level 10
42. ?G = ?H – T?S
Where ?G = free energy change.
?H = enthalpy change.
?S = entropy change.
New answer posted
5 months agoContributor-Level 10
(i) Mass of an electron = 9.10939*10−31 kg = 9.1 * 10-28 g
⇒ No. of electrons in 9.1 * 10-28 g = 1 electron
Therefore, No. of electrons in 1 g = 1/9.1 * 10-28 = 1.098*1027
(ii) One mole of electrons = 6.022 * 1023 electrons
Mass of 1 electron = 9.1 * 10-31 kg
Mass of 6.022 * 1023 electrons = (9.1 * 10-31kg) * (6.022 * 1023) = 5.48 * 10-7 kg
Charge on one electron = 1.602 * 10-19 C
Charge on one mole electrons = 1.602 * 10-19 * 6.022 * 1023 = 9
New answer posted
5 months agoContributor-Level 10
41. Amount of heat required to vapourize one mole of a liquid at constant temperature and under standard pressure (1bar) is called its standard enthalpy of vapourization or molar enthalpy of vapourization, ΔvapH?.
New answer posted
5 months agoContributor-Level 10
40. (i) First law of thermodynamics: It states that energy can neither be created nor be destroyed. The energy of an isolated system is constant.
?u = q + w
(ii) The standard enthalpy change for the formation of one mole of a compound from its elements in their most stable states of aggregation (also known as reference state is called Standard Molar Enthalpy of Formation. Its symbol is Δf H?, where the subscript ' f ' indicates that one mole of the compound in question has been formed in its standard state from its elements in their most stable states of aggregation.
New answer posted
5 months agoContributor-Level 10
39. In thermodynamics, a distinction is made between extensive properties and intensive properties. An extensive property is a property whose value depends on the
quantity or size of matter present in the system. For example, mass, volume, internal energy, enthalpy, heat capacity, etc. are extensive properties.
Those properties which do not depend on the quantity or size of matter present are known as intensive properties. For example, temperature, density, pressure etc. are intensive properties.
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