Convert 3.01€22 molecules of O²(a) mole of O²) ,volume at S. T.P, no of Oxygen atom. (d) mass

a )0.05 moles of O₂

b) 1.1207 dm³

c) 0.3× 10²³ atoms of oxygen

d) 1.6 g

Explanation:

Given data:

Number of molecules of O₂ = 3.01 × 10²² molecules

Number of moles of O₂ = ?

Volume of oxygen at ATP = ?

Number of oxygen atoms = ?

Mass of oxygen = ?

Solution:

The given problem will solve by using Avogadro number.

"It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance".  The number 6.022 × 10²³ is called Avogadro number.

Moles of oxygen:

1 mole = 6.022 × 10²³  molecules

3.01 × 10²² molecules  × 1 mol  / 6.022 × 10²³  molecules

0.05 moles of O₂

Number of atoms of oxygen:

1 mole = 6.022 × 10²³ atoms

0.05 mol × 6.022 × 10²³ atoms /1 mol

0.3× 10²³ atoms of oxygen

Volume of oxygen:

1 mole of oxygen at STP occupy 22.414 dm³

0.05 mol × 22.414 dm³ / 1mol

1.1207 dm³

Mass of oxygen:

Mass = number of moles × molar mass

Mass = 0.05 mol  × 32 g/mol

Mass = 1.6 g

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.