The periodic table, chemistry calculations, salts test Flashcards
why could there be an apparent increase in mass?
gases in the air that would be not able to be weighed might be used in the reaction
why could there be an apparaent decrease in mass?
gases produced by the reaction would be diffused into the air, therefore could not be weighed.
what is the the law of conservation of mass?
- no atoms are lost or made during a chemical reaction so the mass of the products equals to the mass of the reactants
How do you calculate the RFM of a sbustance
relative atomic mass of all atoms added together
how do you caculate the %mass of an element in a compound?
mass of element in compound/ RFM of compound x 100
How do you calculate uncertainty?
range of results/ 2
or
result + or - resolution/ 2
What are chemical amounts measured in?
moles (symbol = mol)
how much is one mol of a substance?
same number as RFM of the substance but in grams. (eg. 1 mol of oxygen = 16 g)
how much is one mole of any substance compared to another?
the same amount of particles, atoms, ions, etc.
What is the value of the avogrado constant?
6.02 x 10^23 per mole
how do you calculate the number of moles?
moles = mass/ RFM
Reacting mass calculations
balancing number
known/ unknown mass
RFM
mass (RFM x balancing number)
statement of what is happening
divide to find mass produced from 1g
multiply by mass of reactant
How do you balance equations using reacting masses?
unbalanced symbol equation
masses that reacted in g from question
RFM
Moles (mass/ RFM)
divide by smallest ratio
balanced equation
How do you calculate concentration? (g/dm^3)
amount of substance (g) / volume of solution (dm^3)
what are the three most common acids?
- hydrochloric acid (HCl)
- Sulfuric acid (H2SO4)
- nitric acid (HNO3)
Types of salt that can form from the acids
- nitrate
- cholide
- sulfate
What can salts be used for?
- seasoning food
- dissolved in drinking water
- perserve food
- fertilizers (sulfate and nitrate salts)