Answer:
Only 4 %
Explanation:
Just about 4 percent of the known universe overall mass consists of atomic nuclei and is therefore described by chemical components. This proportion is around 15 percent of the total mass, with dark energy becoming the majority of the material .
A mixture
having a uniform composition where the components can't be seen separately and
all components are in the same state best describes a solution.
<span>In chemistry, a </span>solution<span> is a
homogeneous mixture composed of two or more substances. In such a mixture, a
solute is a substance dissolved in another substance, known as a solvent.</span>
The correct answer between all
the choices given is the third choice or letter C. I am hoping that this answer
has satisfied your query and it will be able to help you in your endeavor, and
if you would like, feel free to ask another question.
The net ionic equation of the reaction is:
- Pb²⁺ (aq) +2 I⁻ (aq) → PbI2(s)
<h3>What are net ionic equations?</h3>
Net ionic equations are equations where ions which remain in solution known as spectator ions are not shown in the equation. Only ions involved in formation of product are shown.
In the given equation, sodium and nitrate ions are spectator ions.
The net ionic equation of the given reaction is as follows:
- Pb²⁺ (aq) +2 I⁻ (aq) → PbI2(s)
In conclusion, spectator ions are not shown in net ionic equation.
Learn more about net ionic equations at: brainly.com/question/19705645
#SPJ1
Answer:
13. Na 14. Ne. 15. U. 16. Ca. 17. C. l 18. O. 19. Cl. 20. Si 21. U 22. N.
23. Na 24. Ne. 25. U 26. Sc. 27. N 28. O 29. Cl 30. Si 31. U 32. N.
Explanation:
The general trend as you go to the right in any one period is for the size to decrease.
The general trend is that the size increases as you go down a Group.
The general trend as you go from the bottom left to the top right is a decrease in size.
Ionization energy increases as we move to the right in a period.
It decreases as we move down a group.
Going from the bottom left to top right - the ionization increases.
Answer: (a) There are 0.428 moles present in 12 g of 
molecule.
(b) There are 2 moles present in 
particles of oxygen.
Explanation:
(a). The mass of nitrogen molecule is given as 12 g.
As the molar mass of is 28 g/mol so its number of moles are calculated as follows.
So, there are 0.428 moles present in 12 g of molecule.
(b). According to the mole concept, 1 mole of every substance contains 
atoms.
Therefore, moles present in particles are calculated as follows.
So, there are 2 moles present in particles of oxygen.
