1.6 Calculations Involving Masses Flashcards
What is the Empirical formula?
The simplified formula
List the limitations of the following models when representing ionic compounds:
Dot and Cross
2D diagrams
3D diagrams
Dot and Cross-No lattice structure or ionic bonds
2D diagrams-Only shows one layer, doesn’t show formation of ions
3D diagrams-Shows spaces between the ions, doesnt show charges
List the limitations of the following models when representing covalent molecules:
Dot and Cross diagrams
Ball and Stick diagrams
Dot and Cross-doesn’t show relative sizes of atoms or intermolecular forces
Ball and Stick diagrams-Bonds shown as sticks rather than forces, doesn’t show how covalent bonds form
How do you calculate the relative formula mass of a compound?
Add together all the relative atomic masses of the elements in the compound
What 2 values could be used to calculate the empirical formula of a simple compound?
Reacting masses or percentage Composition
What is the molecular formula?
Actual number of atoms of each element in a compound
What is the law of the conversation of mass?
No matter is lost or gained during a chemical reaction
If a reaction is carried out in a closed system what can you say about the total mass of the reaction throughout the experiment?
Mass stays constant
If a reaction is carried out in an open flask and a gas is produced, what can you say about the total mass of the reaction throughout the experiment?
Mass decreases as the gas escapes
What equation links mass, moles, and relative atomic mass?
Mass (g)=Moles x relative atomic mass
How can you calculate concentration in g/dm3?
concentration (g/dm3)=Mass(g) x Volume (dm3)
What is the Avogardo constant?
The number of atoms, molecules or ions in 1 mole of a given substance
6.02 x 10^23
What formula links Avogardos constant, moles and number of particles?
Number of particles = Avogardos constant x moles
What is a limiting reagent in a chemical reaction?
The chemical that is used up first in a reaction preventing the formation of more product.
