| Where is the Relative atomic mass in an element in the Periodic Table? | This is usually the bigger number of the two. |
| The Relative Atomic mass of an element is the average mass of what? | Average mass of one atom of the element |
| What is an Isotope? | This is an atom with a different number of Neutrons |
| If an element has one more isotope, what would happen? | The relative mass will be the same as the Mass Number |
| If an element had more then one isotope, what would happen? | The relative mass will be dependent on all of the mass numbers of the different isotopes.
The number of how much there is will also be factored in |
| Name an Example of an element having more then one isotope? | Chlorine. They had two stable Isotopes [Chlorine-35] [Chlorine-37]
They is a lot of Chlorine-35 but not a lot of Chlorine-37. So the Relative Atomic Mass is 35.5 |
| What is the Relative Formula Mass | This is all of the relative atomic mass added up together in a Compound |
| How can you find it out? [Relative Formula Mass] | In the Periodic Table, Find the elements in the Compound and add them up together. If the Element is like O2, just multiply the Relative mass by 2 to get both atoms Relative Mass
If it has brackets in, Just see what elements are in, find the Relative mass and see the number outside the bracket. If its a small 3, then multiply it your Relative Mass by 3. |
| What does a Molecular Formula and Displayed Formula show? | This shows the number of Atoms and also the type of it too. [Molecular Formula]
This shows the atoms and covalent bond in a molecule as a picture [Displayed Formula] |
| Do an Example with Methane [Displayed Formula] | It would look like...........H
..................................H...C...H
........................................H
This is saying there is one Carbon atom, and 4 Hydrogen atoms.
[CH4]--->[Molecular Formula] |
| What would happen if you had to find the Displayed Formula for an Element with Brackets? | Take [CO2]² So Carbon will have a Carbon in the middle along with 2 oxygen molecules top and bottom of Carbon. The ² symbol is indicating they're two lots of CO2. So there would be Two lots of the Molecular Formula for CO2 |
| What is a Empirical Formula? | This is the Simplest Ratio of Atoms |
| Example of Empirical Formula with Glucose | In glucose, The molecular Formula is C6,H12,06.
In ratios thats 6:12:6. Now to simplify it, find a common factor and divide it. higher equals better for common factor.
For this case, 6 will be it making our ratio become simplified to
1:2:1. Now put back the Elements in which will give us the answer:
CH2O |
| How can you find out the Molecular Formula with the Empirical Formula and the Relative Mass? | Example. Compound N has a Empirical Formula of C2,H6,N
Compound N has a Relative Mass of 88
What is the Molecular Formula for Compound N?
-First find the Relative Mass for the Elements involved. In this case, Carbon is 12, Hydrogen is 1 and Nitrogen is 14.
Now multiply with the amount of atoms on the Empirical Formula and then add them all up to get the Relative mass of the Empirical Formula
In this case it will look like
[2 x 12]-->[Carbon] + [6 x 1]--->[Hydrogen] + [14 x 1]--->[Nitrogen] =
44
Now do the Relative mass of the Compound N divided by the Relative mass of the Empirical Formula [88/44 = 2]
Now, the final step involves the answer you just got [ours is 2.] Multiply the atoms in the Empirical Formula by your Answer
[2 x 2 = 4] (Carbon) [6 x 2 = 12] (Hydrogen) [1 x 2 = 2] (Nitrogen)
Now you have found your Molecular Formula. Ours is:
C4,H12.N2 |
