C3.1 Chemical Reactions Flashcards
What is the formula for metal elements always written as?
Empirical because they exist as giant lattices
What group exists as diatomic molecules?
Group 7(covalently bonded)
Which other elements exist as diatomic?
Hydrogen, nitrogen, oxygen
Which other elements exists as weird molecules?
Sulphur(S4)
Phosphorus (P4)
Stage the orders of charges of groups
+1,+2,+3,-4,-3,-2,-1,0
What is each row in the periodic table and what does it determine?
Period, number of electron shells
What is each column in the periodic table called and what do they have in common
Group, electrons in the outer shell
What charge does a hydrogen ion have?
H+
Ammonium ion
NH4+
Carbonate ion
Co3 ^2-
Sulfate ion
So4 ^2-
Hydroxide and nitrate ion
OH-, NO3-
What is the law of conservation of mass?
Atoms cannot be created or destroyed in chemical reactions, they are just joined in different ways
Describe an experiment you can use to show that mass is conserved
Carry out a reaction in a closed system where nothing can leave or enter. Measure the reactants before and after they react
Why does mass sometimes change?
Some products can leave if it is a non enclosed system, probably gases
Why does mass sometimes go up in reactions?
When a metal reacts with oxygen it produces a metal oxide where the oxygen atoms add mass
What is a half equation?
A model for the change that happens to one reactant in a chemical reaction. You are usually asked to write 2 or more
What must your remember to do when writing half equations?
Write the charges of the ions on both sides
Ignore the big number such as the 2 in 2Na
Don’t ignore the subscript numbers
Never write something to lose electrons
Balance using only big numbers
State symbols
What is an ionic equation?
An equation which only shows the ions present in a reaction mixture without spectator ions
What is a precipitate?
A solid formed in a reaction of liquids
What is a mole?
The amount of any substance which contains the same number of entities as there are atoms in 12g of carbon 12
How many atoms does one mole have?
6.02x10^23
Avagadros constant
What is avagadros constant?
The number of entities in one mole
Formula for moles and mass
Moles(mol)= mass(g) / molar mass(g/mol)
What is a limiting reactant?
What determines the amount of final product formed and runs out the quickest
