Answer:
The correct answer is option C
Explanation:
According to Heisenberg's principle "At the instant of time when the position is determined, that is, at the instant when the photon is scattered by the electron, the electron undergoes a discontinuous change in momentum. This change is the greater the smaller the wavelength of the light employed, i.e., the more exact the determination of the position. At the instant at which the position of the electron is known, its momentum therefore can be known only up to magnitudes which correspond to that discontinuous change; thus, the more precisely the position is determined, the less precisely the momentum is known".
Hence, this principle made scientists to realize that electrons could not be located in defined orbits which a contradictory of Bohr's model.
Answer:
c. uracil
Explanation:
uracil is not found in DNA. the missing base would be thymine
Chemical,when you light a match stick, you are starting a chain reaction of the substance chemical formula, making it a chemical change
Answer : The molarity of calcium ion on the original solution is, 0.131 M
Explanation :
The balanced chemical reaction is:

When calcium nitrate react with potassium carbonate to give calcium carbonate as a precipitate and potassium nitrate.
First we have to calculate the moles of 

Given:
Mass of
= 0.524 g
Molar mass of
= 100 g/mol

Now we have to calculate the concentration of 

Now we have to calculate the concentration of calcium ion.
As, calcium carbonate dissociate to give calcium ion and carbonate ion.

So,
Concentration of calcium ion = Concentration of
= 0.131 M
Thus, the concentration or molarity of calcium ion on the original solution is, 0.131 M
Answer:
The mass of potassium required to produce a known mass of potassium chloride
Explanation:
Stoichiometry deals with the relationship between amount of substances, mass of substances or volume of substances required in a chemical reaction. Stoichiometric relationships may involve reactants alone or reactants and products. These relationships are normally in the form of simple proportion.
A typical example is our answer option, the mass of potassium required could be used to determine the mass of potassium chloride produced after a balanced reaction equation is written.