Finding the amount of molecules in compounds using mole conversions

[Hannah_Kim_1I]

Could someone explain how 1 mol = 6.022 x 10²³ atoms but can also equal 6.022 x 10 ²³ molecules? Also, there is a problem in the textbook that says to "Calculate the amount of urea molecules, OC(NH₂)₂ in 2.5 x 10⁵ g of urea," but gives the answer (3.8 x 10³) in moles. If 1 mol = 6.022 x 10²³ molecules, shouldn't the answer be 2.3 x 10²⁷ molecules?

[Brianne Conway 1D]

6.022x10^23 is a constant that can apply to anything, it's just an easier way of describing quantities of atoms or molecules without having to work with big, complicated numbers. Pretty much how kilo- means 1000 of whatever it is you're working with (grams, meters, etc.), a mole is just 6.022x10^23 of whatever you're working with (atoms, molecules, etc.). It just makes calculations and stuff easier since you can work with much smaller numbers. And yes, your conversion of moles of urea to molecules is correct.

[lauren_tran_1L]

Could someone explain how 1 mol = 6.022 x 10²³ atoms but can also equal 6.022 x 10 ²³ molecules? Also, there is a problem in the textbook that says to "Calculate the amount of urea molecules, OC(NH₂)₂ in 2.5 x 10⁵ g of urea," but gives the answer (3.8 x 10³) in moles. If 1 mol = 6.022 x 10²³ molecules, shouldn't the answer be 2.3 x 10²⁷ molecules?

to answer the second part of your question. It might be a typo! But in the end they are the same value just in different units.

[DominicMalilay 1F]

Along with Briannes reply, Avogadro's constant is exactly that, a constant that does not have specific units in terms of atoms, photons, molecules, or any other unit for measurement. This means it can be applied in many situations either to cancel out some units or to convert moles into molecules.