Chapter #5 - Chemical Calculations Flashcards
What is the defenition of relative mass?
Mass of a substance compared to carbon.
What is the defenition of mole (amount)?
Mass of a substance required to have 6 x 10^23 atoms.
What elements exist only as individual atoms?
Noble gases
What is the table to find the empirical formulae of a substance?
What is the defenition of empirical?
Derived from experiments.
What is the defenition of empirical formula?
Chemical formula calculated from an experiment, expressed as the lowest ratio of elements.
What is Ar?
With the “r” small at the bottom.
Relative atomic masss.
What is 0.2/ 0.4/ 0.6
1/5
What is 0.25/ 0.75?
1/4
What is 0.33/ 0.67?
1/3
What is 0.5?
1/2
What does the molecular formula represent?
It tells you how much atoms there are in the molecule (represents how they are bonded).
Ionic structuer=
Lattice of alternating cations and anions arranged ina pattern held together with electrostatic forces.
What is in between particles?
There are spaces (nothing)
How do you represent when something is not bonded but is in the spaces between that atoms in an equation?
.
What is a hydrated compound?
A compund that has water in its spaces.
What is it called when a compound has nothing in its spaces?
Anhydrous.
What does the size of the spaces between the particles in a molecule depend on?
The ratio of ionic radii.
What can fit in some of the spaces between atoms in a molecule?
SMALLER water molecules.
What does the Mr mean?
The mass needed to have 6 x 10^23 molecules
How do you calculate the molecular formula from the emperical formula table?
What is the chemical test for water?
Anhydrous copper sulfate => white => blue
What are the steps to find mass of a substance in a reaction?
- Write a balanced symbol eqn.
- Calculate the no. of mols of the chemical given.
- Use the co-efficients from the eqn, to determine the n. of the 2nd substance (Chemical you have to chemical you want).
- Convert the n. into mass/ volume/ concentration.
What are the steps to find volume of a substance in a reaction?
- Write a balanced symbol eqn.
- Calculate the no. of mols of the chemical given.
- Use the co-efficients from the eqn, to determine the n. of the 2nd substance (Chemical you have to chemical you want).
- Convert the n. into mass/ volume/ concentration. (REMEMBER TO USE VOLUME AS INSTEAD OF MASS)
What does the volume of a gas depend on?
- The no. of moles
- The temperature (directly proportional)
- The preassure (inversley proportional)
What is stp?
Standard temp. preassure = 0 celcius,101000, 1 atm
What is rtp?
rtp (room temp.) = 20 celcius, 101000 Pa, 1 atmpstphere
What is the rule for how much volume the same no. of gas particles occup
The same no. of particles of any gas always occupies the same volume of space.
What is the stp.and rtp, of 1 mol of any gas?
stp. = 22400cm3
rtp. = 24000cm3
What is the defenition of limiting reagent?
The reactent that is not in excess.
What is mass concentration?
The measure of the concentration of a solution in terms of the mass of rge solute, in grams, dissolved per cubic decimeter of solution (g/dm^3)
What is molar concentration?
The measure of the concentration of a solution in terms of the number of moles of the solute dissolved per cubic decimetre of solution (mol/dm^3)
What do you use when calculating the product made?
(limiting reagent or excess reagent)
The limiting reagent.
