Answer: shining a bright light on the object and testing for decomposition
Decomposition is the separation of a molecule into its elements or simpler compounds.
And a chemical property is the ability of a
substance to combine or to become one or more substances.
Then, testing the ability of an object for decomposition is testing a chemical property.
The accepted model of the atom was changed.
The answer to this item depends entirely to the chemical reaction. If the compound, NH4Cl, is in the left hand side of the reaction, when it is added, the reaction will shift to the left. In the same manner, when the compound is in the right-hand side of the reaction, the reaction will shift to the right.
This happens because initially the reaction is in equilibrium and adding another compound to it will most likely lead to the shifting of the reaction.
Atomic mass of Potassium = Mass of 1 atom of Potassium = 39.1 amu
Then
Mass of 6.02 x 1023 atoms of potassium = 39.1 x 6.02 x 1023 amu
=
We already know that
1 mole = 6.02 x 1023 atoms
Also
Number of mole = mass in grams/ atomic mass
Then
Mass in gram = Number of mole x atomic mass
= (39.1 x 6.02 x 1023)/(6.02 x 1023)
= 39.1 g
The correct option among all the options that are given in the question is the third option or option "B".
Answer:
43.13Kg of melamine
Explanation:
The problem gives you the mass of urea and two balanced equations:

First we need to calculate the number of moles of urea that are used in the reaction, so:
molar mass of urea = 
The problem says that you have 161.2Kg of urea, so you take that mass of urea and find the moles of urea:
161.2Kg of urea
2684 moles of urea
Now from the stoichiometry you have:
2684 moles of urea
= 447 moles of melamine
The molar mass of the melamine is
so we have:
= 5637.64 g of melamine
Converting that mass of melamine to Kg:
5637.64 g of melamine *
= 56.38 Kg of melamine, that is the theoretical yield of melamine.
Finally we need to calculate the mass of melamine with a yield of 76.5%, so we have:
%yield = 100*(Actual yield of melamine / Theoretical yield of melamine)
Actual yield of melamine =
= 43.13Kg of melamine