Mole Concept and Stoichiometry

Question 1

define gas laws

Answer 1

certain rules which a gas follows when subjected to a change in temperature, pressure, or volume

Question 2

Gay Lussac’s Law

Answer 2

When gases react, they do so in volumes which bears a simple whole number ratio to one another and to the volumes of the products, if gaseous, provided the temperature and pressure of the reacting gases and their products remains constant

Question 3

Avogadro’s law

Answer 3

under the same conditions of temperature and pressure, equal volumes of all gases contain the same number of molecules

Question 4

relative mass of an atom

Answer 4

considered by considering a mass of a light atom and relating the mass of other atoms/molecules to it

Question 5

define RAM

Answer 5

RAM of an element is the number of times on atom of that element is heavier than 1/12th the mass of a C-12 atom

Question 6

define mole

Answer 6

a mole is the amount of substance which contains the same number of units as the number of atoms in 12.000 g of C-12

Question 7

define Avogadro’s number

Answer 7

Avogadro’s number is the number of atoms present in 12 g of C-12
(no. of elementary units in one mole of a substance)
denoted by NA or L

Question 8

applications of Avogadro’s law

Answer 8

1. determines atomicity of gas
2. determines molecular formula of gas
3. determines relation between molecular weight and vapour density
4. explains Gay-Lussac’s Law
5. determines relationship between gram molecular weight and gram molecular volume

Question 9

define atomicity

Answer 9

no. of atoms present in one molecule of that element

Question 10

define molecular formula

Answer 10

a chemical formula which gives the actual or exact number of atoms of the elements present in one molecule of a compound

Question 11

define molecular weight

Answer 11

ratio of weight of one molecule of a substance to the weight of one atom of hydrogen

Question 12

define vapour density

Answer 12

ratio of mass of a certain volume of gas or vapour t the mass of the same volume of hydrogen

Question 13

relationship between VD and molecular weight

Answer 13

2 * Vapour density= RMM

Question 14

define gram molecular volume

Answer 14

the volume occupied by 1 g molecular at. of a gas at STP

Question 15

define percentage composition

Answer 15

the percentage by weight of each element in the compound

Question 16

define empirical formula

Answer 16

formula of a compound which shows the simplest whole number ratio between the atoms of the elements in the compounds.