Calculate the number of C atoms in 11g of carbon dioxide

1.51× 10²³ C atoms

Explanation:

Given data:

Mass of CO₂ = 11 g

Number of atoms in 11 g of CO₂  = ?

Solution:

First of all we will calculate the number of moles of CO₂ .

Number of moles = mass/ molar mass

Number of moles = 11 g/ 44 g/mol

Number of moles = 0.25 mol

One mole of  CO₂ contain 1 mole of C atom.

0.25 mole of CO₂ contain 0.25 moles of C atom.

The number of C atoms in 0.25 moles 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 .

11 g of CO₂ = 0.25 moles of C = 0.25 × 6.022 × 10²³ C atoms

1.51× 10²³ C atoms

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).