Answer: 
Explanation:
Electronic configuration represents the total number of electrons that a neutral element contains. We add all the superscripts to know the number of electrons in an atom.
The electrons are filled according to Afbau's rule in order of increasing energies where orbital with higher value of (n+l) has higher energy as compared to orbital having lower (n+l) value. Thus the electronic configuration for calcium with atomic number of 20 and hence containing 20 electrons is :
Answer:
The molarity of the solution is 4M
Explanation:
Molarity is defined as the amount of moles of solute present in one liter of solution. So the molarity of any solution can be found by dividing the moles of solute between the volume in liters of the solution.
For this case we have:
Answer:
Less than
Explanation:
The process of dissolution occurs as a kind of "tug of war". On one side are the solute-solute and solvent-solvent interaction forces, while on the other side are the solute-solvent forces.
Only when the solute-solvent forces are strong enough to overcome the pre-mixing forces do they overcome the "tug of war", and thus dissolution occurs.
Thus, it is concluded that the interaction forces between solute particles and solvent particles before they are combined are less than the interaction forces after dissolution.
Answer:
In order to determine the rate at which the sediment layers were deposited
Explanation:
Iridium is an important element that belongs to the Platinum group and they are dominantly present in the asteroids and comets. They are the key evidence that suggests the occurrence of an asteroidal impact or a mass extinction event that has taken place in the geological past.
The presence of Iridium mixed with the clay sediments in the boundary between the Cretaceous and Tertiary (K-T boundary) suggested the mass extinction event that wiped out numerous life forms from the earth.
The famous scientist Dr. Luis Walter Alvarez suggested measuring the concentration of Iridium in this K-T boundary in order to determine the rate at which these sediment layers were deposited. They were able to determine that these Iridium elements were present due to the asteroid impact on earth, that wiped out the dinosaurs from the earth. They also considered that this element can be produced from the eruptions of volcanoes.
Explanation:
The given data is as follows.
= 225.5 mL, 
= 45.00 mL
= 0.09988 M, 
= ?
Therefore, formula to calculate final concentration will be as follows.
= 
Putting the given values into the above formula as follows.
=
= 
= 0.5 M
Thus, we can conclude that the final concentration of the given solution is 0.5 M.
