Booklets Flashcards
How small is the radius of an atom? (B Ch)
0.1 nm OR 1x10 to the power of -10
How small is the radius of a nucleus of an atom? (B Ch)
1 x 10 to the power of -14
How did scientists order the periodic table before the discovery of protons neutrons and electrons? (B Ch)
in order of their atomic weights
What does the amount of energy required for a change of state depend on? (B Ch)
the strength of the forces between the particles of the substance. The nature of the particles involved depends on the type of bonding and the structure of the substance. ~ The stronger the forces between particles the higher the melting point and boiling point of the substance.
What are the limitations of a simple particle model? (B Ch)
- no forces
- all particles are represented as spheres
- spheres are solid.
What are chemicals measured in? (B Ch)
moles (mol)
What does the relative formula mass refer to? (B Ch)
the mass of one mol of a substance in grams
what is the value of Avagadro’s constant? (B Ch)
6.02 x 10 to the power of 23 per mole
What is the meaning of Avagadro’s constant? (B Ch)
The number of atoms, molecules or ions in a mole of a given substance. The value of the Avadgadro’s constant is 6.02 x 10 the the power of 23
What is a limiting reactant? (B Ch)
In a chemical reaction involving two reactants, it is common to use an excess of one of the reactants to ensure that all the other reactant it used. THe reactant that is completely used up it called the limiting reactant because it limits the amount of products
What is the equation that allows you to work out the volumes of gaseous reactants of products? (B Ch)
moles = actual volume / molar volume
where the molar volume is 24dm3 or 24000cm3
How is aluminium manufactured? (B Ch)
by the electrolysis of a moltern mixture of aluminium oxide and cryolite using carbon as the positive electrode (anode)
