Question

In the field of chemistry, a mole is defined as the amount of a substance
that contains exactly 6.02214076 * 10 23 ‘elementary entities’ of the given
substance.
The number 6.02214076*10 23 is popularly known as the Avogadro constant and is often denoted
by the symbol ‘N A ’. The elementary entities that can be represented in moles can be atoms,
molecules, monoatomic/polyatomic ions, and other particles (such as electrons).
For example, one mole of a pure carbon-12 ( 12 C) sample will have a mass of exactly 12 grams
and will contain 6.02214076*10 23 (N A ) number of 12 C atoms. The number of moles of a substance
in a given pure sample can be represented by the following formula:
n = N/N A
Where n is the number of moles of the substance (or elementary entity), N is the total number of
elementary entities in the sample, and N A is the Avogadro constant.
The word “mole” was introduced around the year 1896 by the German chemist Wilhelm Ostwald,
who derived the term from the Latin word moles meaning a ‘heap’ or ‘pile.

(i) How many moles of iron are present in a pure sample weighing 558.45 grams?
a) 10 moles
b) 20 moles
c) 30 moles
d) 5 moles

(ii) How many grams of carbon can be found in 1 mole of carbon dioxide?
a) 1 g
b) 5g
c) 12 g
d) 14 g

Answer 1

Answer:

Explanation:One mole (mol) contains exactly 6.02214076 × 1023 elementary entities. This number is the fixed numerical value of the Avogadro constant, NA, when expressed in the unit mol−1 and is called the Avogadro number. The amount of substance, symbol n, of a system is a measure of the number of specified elementary entities.

Answer 2

Answer:

One mole (mol) contains exactly 6.02214076 × 1023 elementary entities. This number is the fixed numerical value of the Avogadro constant, NA, when expressed in the unit mol−1 and is called the Avogadro number. The amount of substance, symbol n, of a system is a measure of the number of specified elementary entities.

Explanation: