How many moles and molecules are there in 250g of hydrogen nitrate, hno3

Number of molecules = 23.9  × 10²³ molecules

Number of moles = 3.97 mol

Explanation:

Mass of HNO₃ = 250 g

Number of moles = ?

Number of molecules = ?

Solution:

Number of moles = mass / molar mass

Number of moles = 250 g/63 g/mol

Number of moles = 3.97 mol

Number of molecules:

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 250 g of HNO₃:

250 g/ 63 g/mol = 3.97 mole

3.97 × 6.022 × 10²³ molecules = 23.9  × 10²³ molecules

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.

- lead + phosphoric acid = hydrogen + lead(ii) phosphate