C3.1 - Introducing chemical reactions Flashcards
Why are the formulae of metal elements always written as empirical formulae? (2)
- because they exist as giant metallic lattices
- numbers in the formula would be too big
ie. C 432625 H 736765 N 63910
are the non-metal elemis in group 0 diatomic atoms?
no, they exist as individual atoms
what is special about the elements in group 7?
they are all diatomic (expect astatine)
list all the diatomic molecules (7)
Hydrogen. remember as: Have No Fear Of Ice Cold Beer Nitrogen Fluorine Oxygen Iodine Chlorine Bromine
-
-
give examples of a simple covalent compound
- Carbon dioxide
- methane
- water
explain (in terms of particles), why the mass of the solid increases when copper is heated in the air (3)
- copper atoms react with oxygen atoms in the air
- forms a copper oxide (chemical reaction)
- therefore, mass increases since the solid is made of copper ions and oxygen ions
explain what is meant by the law of conservation of mass
the principle that states that the total mass stays the same during a chemical reaction, because atoms are not created or destroyed
what is a non-enclosed system?
when substances can leave or enter the reaction mixture (usually in an open container)
what is a closed system?
- a container where no substances can enter or leave during the reaction
what do half equations show?
- the change that happens to one reactant in a chemical reaction
define the term ‘mole’
the amount of any substance that contains the same number of entities as there are atoms in 12.0g of carbon-12
define the term ‘Avogadro’s constant’
the number of entities in 1 mole (6.02 x 10^23)
what terms are the same as molar mass?
- relative atomic mass
- relative formula mass
what is molar mass measured in?
grams per mole (g/mol)
what is the equation to calculate the mass of a substance
mass (g)= molar mass (g/mol) x number of moles (mol)
explain the effect of a limiting amount of a reactant
- it determines the amount of product made
what does a stoichiometry describe?
the relative amounts of each substance involved in a reaction
what is the charge of ammonium ions?
+
NH
4
what is the charge on a silver ion?
Ag+
what is the charge on a barium ion?
2+
Ba
what is the charge on a aluminium ion?
3+
Al
what is the charge on a hydroxide ion?
OH-
what is the charge on a nitrate ion?
-
NO
3
what is the charge on an oxide ion?
2-
O
what is the charge on a carbonate ion?
2-
CO
3
what is the charge on a sulfate ion?
2-
SO
4
what do state symbols show?
the physical state of each substance in a chemical equation
what is avogadro’s constant (number)?
6.02 x 10^23
what is a limiting reactant?
The reactant that is completely used up
