# How many Nitrate ions are there in 0.42 mol of Ca(NO3)2?

If you know how to calculate this, can you show the formula and equations and all steps needed to find the answer. Thanks

### 3 Answers

- Lexi RLv 78 years agoFavorite Answer
Each Ca(NO3)2 has 2 NO3^- ions

So moles NO3^- = 2 x moles Ca(NO3)2

= 2 x 0.42 mol

= 0.84 mol

In the same way that 1 dozen of anything = 12 of that anything

1 mole of anything = 6.022x10^23 of that anything

this is called avagadros number

eg

1 mole atoms = 6.022x10^23 atoms

1 mole ions = 6.022x10^23 ions

1 mole eggs = 6.022x10^23 eggs

So to convert moles of ions to number of ions multiply by 6.022x10^23

number NO3^- ions = moles NO3^- ions x 6.022x10^23 ions / mole

= 0.84 mol x 6.022x10^23 ions / mol

= 5.1x10^23 ions

Be mindful of what you are asked to give the number of

for example

the number of molecules in 0.42 moles of Ca(NO3)2

= 0.42 mol x 6.022x10^23 molecules/mole

= 2.5x10^23 molecules

there are 9 atoms in each Ca(NO3)2 moleule

So moles atoms = 9 x 0.42 mol

= 3.78 moles of atoms

therefore

number atoms in 0.42 moles Ca(NO3)2 = 3.78 moles atoms x 6.022x10^23 atoms/mol

= 2.3x10^24 atoms