#Atomic mass of oxygen how to

So we now know we need 10.8 g of NaOH to exactly neutralise our amount of hydrochloric acid. Mole * molecular weight = mass (rearrange the equation)Īs 1.626×10 23 molecules of NaOH is also equal to 0.27 moles, and we know that the molecular weight of NaOH is 40, we can use these numbers to get: Mole = mass / molecular weight (mulitply both sides by molecular weight) As we need to find the mass of NaOH to add, lets quickly rearrange the equation: Now we know the amount of molecules of HCl we have, and, since the reaction is 1:1, we need the exact same number of molecules of NaOH to neutralise it. We can work out the number of molecules by timesing the moles by Avogadro's constant above. Lets plug these numbers into the above equation:

We know we have 10 g of HCl, and it has a molecular weight of 36.5 g / mol.

#Atomic mass of oxygen how to

Let's do a quick example to help explain how to convert from moles to grams, or grams to moles.

If you wanted to find the concentration of the hydrochloric acid, you could use our concentration calculator. Hence, the number of neutrons in Oxygen atom (16 8) 8 It should be noted that The number of electrons in a neutral atom is equal to the number of protons. To know how to calculate moles, the equation is: Now, To get the number of neutrons in an Oxygen atom, look at its atomic mass which is 15.99 rounded to 16, and the number of protons in oxygen is 8. It is therefore useful to find out exactly how many molecules of HCl are in the solution. Now, you want the resulting solution to be perfectly neutral, so you don't want to add too much or to little NaOH, making it too basic or acidic respectively. Lets say you want to neutralise 10 g of hydrochloric acid (HCl in water) with some sodium hydroxide (NaOH). So why do chemists use moles, and why do you need a mole calculator? Well, as we said above, it provides a useful metric when dealing with reactions. Turns out that memorising that definition for my GCSE chemistry exam was pointless. Prior to that, a mole was defined as the number of atoms in 12 grams of carbon-12 (an isotope of carbon). The official International System of Units definition is that a mole is the amount of a chemical substance that contains exactly 6.02214076×10 23 ( Avogadro's constant) atoms, molecules, ions or electrons (constitutive particles), as of 20 th May 2019. A mole is how chemists define an amount of substance, useful when dealing with many different molecules reacting at once (i.e. Just kidding - we're sure you've never heard that joke before. A mole is small, subterranean mammal belonging to the family Talpidae.