C3.1 - Introducing Chemical Reactions Flashcards
What is a diatomic molecule?
An element that always travels in pairs
Which elements exist as diatomic molecules?
The Group 7 elements and hydrogen
Why are metals not diatomic?
They exist only as giant metallic lattices
What does a compound with the suffix “ate” contain (Carbonate, sulfate)?
Oxygen
What does the molecular formula of a covalent compound show?
The symbols for each element in contains
The number of atoms of each element in one of its molecules
What is the law of conservation of mass?
Atoms cannot be created or destroyed in chemical reactions, but they are just joined in a different way
How can the law of conservation of mass be investigated?
A closed experiment, where no substances can move in or out of
What order should you balance different elements in chemical equations?
C - carbon
H - hydrogen
O - oxygen
M - metals
O - others
What is a mole?
A unit for amount of substance
What is the Avogadro constant and its value?
The number of entities in 1 mole
6.02 x (10 to the power of 23)
How do you calculate the number of moles?
Mass / (atomic or formula) mass
What is a limiting reactant?
One reactant is usually in excess in a reaction mixture. The other one is the limiting reactant, because there is not enough of it to react with the other substance