How many molecules are in each of the following compounds or elements?

3) 9.273 x 10^7 grams of chromium (iii) bicarbonate

0.241  × 10³⁰ molecules

Explanation:

Given data:

Mass of Cr(HCO₃)₃ = 9.273 × 10⁷ g

Number of molecules = ?

Solution:

Number of moles = 9.273 × 10⁷ g/ 235 g/mol

Number of moles = 0.04× 10⁷  mol

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.

For example,

18 g of water = 1 mole = 6.022 × 10²³ molecules of water

1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen

For 0.04× 10⁷  moles of Cr(HCO₃)₃:

0.04× 10⁷  moles × 6.022 × 10²³ molecules / 1 mol

0.241  × 10³⁰ molecules

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.

the answer to this question is 3.