1. Defenition :
- to find (a number, answer, etc.) by using mathematical processes. to get a general idea about the value, size, or cost of (something).
- So The definition of calculate is to use reason or common sense to determine something, or to use math to determine an answer.
Note :
"Stoichiometry calculations are based on the fact that atoms are conserved. They cannot be destroyed or created. Numbers and kinds of atoms before and after the reactions are always the same. This is the basic law of nature".
Origin of calculatevv
from Classical Latin calculatus, past participle of calculare, to reckon ; from calculus, pebble, stone used in doing arithmetic, diminutive of calx, limestone: see calciulate
a. to make a computation
b. to rely or depend (on)
Examples of calculate
in a sentence
- calculate the volume of a cylinder:
- I need to calculate how long it will take me to drive to Chicago.
- We calculated the cost of new carpeting for the whole house.
- We need to calculate our chances of success before we invest more money in the business.
CALCULATE OF STOICYOMETRY
1. Defenition :
Stoichiometry is the calculation of relative quantities of reactans and products in chemical reactions.
A stoichiometric amount or stoichiometric ratio of a reagent is the optimum amount or ratio where, assuming that the reaction proceeds to completion:
- All of the reagent is consumed
- There is no deficiency of the reagent
- There is no excess of the reagent.
Example :
1. Problem :
What volume of oxygen at S.T.P. is needed for the complete combustion of 2 dm3 of propane ()? (Hint: and are the products in this reaction (and in all combustion reactions))
Answer :
Write the balanced equation
Find the ratio
Because all the reactants are gases, we can use the mole ratios to do a comparison. From the balanced equation, the ratio of oxygen to propane in the reactants is .
Find the answer
One volume of propane needs five volumes of oxygen, therefore 2 dm3 of propane will need 10 dm3of oxygen for the reaction to proceed to completion
How to do a dilution? What is the formula?
BalasHapusKomentar ini telah dihapus oleh pengarang.
HapusM1V1 = M2V2,
HapusThe Dilution Formula can be used where there is only one solute present, if a reaction is taking place the problem must be approached as a stoichiometry problem.
Komentar ini telah dihapus oleh administrator blog.
Hapusplease explain to rely or depend (on)?
BalasHapusSo, rely is to depend confidently; put trust in (usually followed by on or upon)
Hapus"Copper in nature is present in 2 isotopes, Cu-63 and Cu-65. if the period of relativ atoms (Ar Cu = 63,5) determine each of these isotopic abundances in nature ?
BalasHapusSolution:
BalasHapus1) Write the following equation:
(62.9296) (x) + (64.9278) (1 - x) = 63.546
Once again, notice that 'x' and 'one minus x' add up to one.
2) Solve for x:
x = 0.6915 (the decimal abundance for Cu-63)
Note that this calculation technique works only with two isotopes. If you have three or more, there are too many variables and not enough equations. I hope it's obvious why you wouldn't do this with an element that has only one stable isotope!
By the way, the 'trick' works because the other equation required is:
x + y = 1
We simply went right to y = 1 - x and substitued it immediately without ever writing down the second equation required.