Zusammenfassung der Ressource
Chemistry - C2.3
- In an Atom the number of protons = number of electrons so atoms have no overall charge
- Mass Number = Number of Neutrons + Number of Protons
- Number of Neutrons = Mass Number - Atomic Number
- Atomic Number = Number of Protons
- Isotopes = Atoms of the same element with the same number of protons but a diferent number of neutrons
- An example of a isotope is carbon
- Relative atomic mass compares the mass of atoms of a elements have different isotopes and is an average value
- Is an average value because elements have different isotopes with different mass number
- The relative atomic mass is found from a periodic table and is the big number from an element
- Mole is the formula mass of a substance in grams
- Number of Moles = Mass divided by Molar Mass
- Total of each type of element in reactants = Total of each type of element in products
- Big numbers placed infront of substances in equations only
- Atoms are multiplied by the big number
- % yield = (Actual Mass divided by Theoretical Mass) x 100
- % yield = percentage of what is produced compared to what should have been produced in theory
- Reactants can react in ways that are different to what is expected
- Reactions may not go to completion because it is reversible
- Some products may be lost when it is seperated
- % mass = (Ar x number if elements x 100) divided by Mr
- Percentage of an element in a compound is calculated using Ar and Mr
- Mr = E (Ar x Number of Atoms)
- Relative Formula Mass of compound is the sum of the relative atomic masses of the atoms in the formula
- Empirical Formula = simplest whole number ratio of elements in a compound
- Use the table to calculate
- Write out the formula once you have worked it out
- Balanced Symbol Equation used to find masses of any reactants of products
- Mole quantaties are used to work out masses of substances in the reaction
- Used to work out masses of any substances in the reaction
- Use lumpy bicycle or reacting mass equation