Chapter 5- The Mole Flashcards Preview

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Flashcards in Chapter 5- The Mole Deck (13):

What is the standard for the mole?



What is the mass spectrometre used for?

Seperating different types of atoms due to their mass.


What can the mass spectrometre tell us about?

-No. of isotopes in a given sample of element
-Relatice isotopic mass
-Percentage abundance of Isotopes


Define the relative atomic mass

Average mass of one atom, given that the isotopic mass has been taken into account. (average)


Define Realtive Abundance of an Isotope

How present that isotope is compared to others


Formula for relative atomic mass

Ar= (RIM of first isotope x abundance) + (RIM of second isotope x abundance) / 100


What is avogagros number?

6.02 x 10^23


How many atoms are there in one mole of an element?

Avogadros number


What is the formula for percentage composition?

% of x in a compound containing x = mass of x in 1 mol/ molar mass of compound x 100


Steps for the Empirical Formula

1. Write down symbols of the element that is present
2. Assume that the mass of the sample is in grams
3. Convert masses to moles
4. Find the simplest whole number ratio and divide all by the smallest.
5. If nesscary multiply by a factor to convert all the numbers to whole


What are the parts of the first mole pyramid?

On the top: m= mass
On the bottom: n= no. of mole and Mr = Molar mass


What are the parts of the second mole pyramid?

On the top: N= no. of particles
On the bottom: n= no. of moles and Na= Avogadros Number


Steps to find the molecular formula

Find the Empirical Formula Mass
Molecular Mass should be given to you
Then divide the molecular mass by the empirical formula mass
This should give you a ratio
Use this ratio to and times it by the empirical formula