Chem test - counting atoms, balancing equations, etc Flashcards
Acid reactions with metals
Acid + metal = metal salt + hydrogen
Acid reaction with metal carbonate
Acid + metal carbonate = metal salt + carbon dioxide + water
Acid reaction with metal oxide (neutrilization)
Acid + base = salt + water
A salt is…
A chemical compound formed in a specific structure made by combining an acid and base
Hydrochloric (HCL) acid becomes…
(metal name) chloride
Sulphuric acid (H2SO4) becomes…
(metal name) sulphate
Nitric acid (HNO3) becomes…
(metal name) Nitrate
Carbon acid (H2CO3) becomes…
(metal name) carbonate
What is a chemical reaction?
A chemical reaction describes a chemical change
What is a reactant?
Left side of equation
Where the arrow begins
Contains the chemical(s) you start with
What is a product?
Right side of equation
Where arrow leads to
Contains new chemical(s) formed
What is the coefficient?
Shows how many molecules there are in a specific chemical
What is a subscript?
Shows how many atoms of a specific element there are in a molecule
Chemical reactions and the law of conservation of mass
In a chemical reaction, the law of conservation of mass must be upheld. The same number and same types of atoms going into the equation, must be the same going out (just rearranged)
Can Subscripts be changed?
NO
Can you change the coefficient?
YES
Where do coefficients go?
They go at the front of the chemical formula, not in the middle
Practice! K2CO3 –>
K = 2 C = 1 O = 3 TOTAL = 6
Practice! 2(NH4)2Cr2O7
N = 4 H = 16 Cr = 4 O = 14 TOTAL = 38
What do we do with a coefficient?
When there is a coefficient, multiply it by all of the subscripts.
What do we do with parenthesis?
When there are parenthesis, you must multiply whatever subscript that’s in the parenthesis by the outer subscript
How do we balance equations?
In order to balance an equation, we add in coefficients to make there be the same amount of atoms per element. Basically, making sure there are the same amount of subscripts going in as going out.
What is the 2 and 3 and 3 and 2 rule?
That rule is basically, when there are two subscipts on either side of the arrow and one is odd while the other is even. The Law says that you add the coefficient of the opposite subscript. Ex. CO2 –> CO3 soooo
3CO2 –> 2CO3. now they both have 6.
