Answer:
a. Approximately 
.
b. Approximately 
.
Explanation:
The unit of concentration "
" is equivalent to "
", which means "moles per liter." 
However, the volume of both solutions were given in mililiters 
. Convert these volumes to liters:
.
.
In a solution of volume 
 where the concentration of a solute is 
, there would be 
 (moles of) formula units of this solute. 
Calculate the number of moles of 
 formula units in each of the two solutions:
Solution in a.:
.
Solution in b.:
.
What volume of that 
 (same as 
) 
 solution would contain that many 
For the solution in a.:
.
Convert the unit of that volume to milliliters:
.
Similarly, for the solution in b.:
.
Convert the unit of that volume to milliliters:
. 
 
        
             
        
        
        
Na⁺,SO₄²⁻ is the answer
<h3>Further explanation
</h3>
An ion is an atom or molecule that has a net electrical charge. There are many ions, one of them are sodium ion and sulfate ion.
SO₄²⁻ or Sulfate is a naturally occurring polyatomic ion that consist of a central sulfur atom surrounded by four oxygen atoms with occured widely in everyday life. Sodium ions are important for regulation of blood and body fluids, transmission of nerve impulses, heart activity, and certain metabolic functions.
Whereas Na⁺ or Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sulfate ion is a very weak base. Therefore sulfate ion undergoes negligible hydrolysis in aqueous solution.
Enter the symbol of a sodium ion, Na⁺, followed by the formula of a sulfate ion, SO₄²⁻. Separate the ions with a comma only—spaces are not allowed. Express your answers as ions separated by a comma. Therefore the answer is: Na⁺,SO₄²⁻ 
Hope it helps!
<h3>Learn more</h3>
- Learn more about sodium ion brainly.com/question/6839866
 - Learn more about sulfate ion brainly.com/question/2763823
 - Learn more about ions brainly.com/question/11852357
 
<h3>Answer details</h3>
Grade:  9
Subject:  Chemistry
Chapter:  Introduction to Mastering Chemistry
Keywords: sodium ion, sulfate ion, ions, Chemistry, symbol 
 
        
                    
             
        
        
        
Answer:
The chemical reaction in which solid calcium oxide is treated liquid water is an example of Synthesis reaction. Hence, the answer is (D) Synthesis.
Explanation:
The formula of Calcium Oxide is CaO.
The formula of liquid water is H₂O.
Calcium Oxide reacts with water and forms Calcium Hydroxide. The Chemical equation is shown below.
CaO + H₂O --> Ca(OH)₂.
This is a Synthesis reaction because Ca(OH)₂ is synthesized by using Calcium Oxide and water.
The product of this reaction is calcium hydroxide, also known as slaked lime.
Thus, when calcium oxide reacts with water, slaked lime is produced.  
Calcium oxide is also known as lime and is most commonly used for many purposes. It can be used for pH correction of water or for its disinfection (with excess lime). 
 
        
             
        
        
        
Given the mass of 
=25.6 g
The molar mass of 
=390.35g/mol
Converting mass of 
to moles:

Converting mol 
to mol S:

Converting mol S to atoms of S using Avogadro's number:
1 mol = 
