Flashcards in Chapter 5 : Quantifying chemistry Deck (17):

1

## Standard measure

###
Carbon-12

It is used as the standard for comparing relative atomic masses

2

## Mass spectrometer

###
Deflects the path of the lightest element the most and the highest charged particle the furthest therefore giving;

No. of isotopes

Relative isotopic mass of each isotope

Percentage abundance of isotopes

3

## Relative isotopic mass

### Is the mass of a single isotope and is determined y comparing the mass of ions of the isotope to the value of a standard carbon-12

4

## Relative abundance

### How much of an isotope is present compared with other isotopes in that element

5

## Relative atomic mass

### Represents the average mass of one atom taking into consideration the number of isotopes and their relative abundance

6

## Relative atomic mass calculation

###
(RIM of first isotope x abundance) + (RIM of second isotope x abundance) ...

divided by 100

7

## Relative molecular mass

### The sum of the relative atomic masses of elements in the formula

8

## The Mole

### The amount of a substance that contains as many particles (atoms, ion of molecules) as there are atoms in exaclty 12g of the carbon-12 isotope

9

## Avagadros number

### 6.02 x 10^23

10

## Molar mass

### Is the mass of 1 mol of the element

11

## Changing moles to number of particles

###
n = m divided by M, n = moles, m = mass and M =molar mass

To go from particles to moles you divide by avogadros number, to go from moles to particles you multiply by avogadros number

12

## Changing mass to moles and moles to mass

###
n=m divided by M

m= n x M

13

## Percentage composition

### The composition of a compound is often expressed in terms of the percentage that each element contributes to its mass

14

## Formula for percentage composition

###
% of x in compound = mass of x in 1 mol of compund divided by molar mass of compund

x 100

15

## Calculating percentage compostion of hydrated compunds

### They can be calculated when both the hydrated compound and the anhydrous compound masses are known

16

## Empirical formulas

### Is the simplest whole number ratio of atom or ion present in a compound

17