Explanation:
Given elements: 
   F, Sr, P, Ca, O, Br, Rb, Sb, Li, S
Elements with the same chemical reactivity will belong to the same group on the periodic table. This implies that elements in the same column will have the same reactivity; 
   Li and Rb are both alkali metals in group 1
   Ca and Sr are both alkali earth metals in group 2 
   F and Br are halogens in group 7 
   O and S are group 6 elements 
  P and Sb are both in group 5 on the periodic table 
So these groupings show elements with the same chemical properties. 
 
        
             
        
        
        
Answer:
[NaOH} = 0.4 M
Explanation:
In a reaction of neutralization, we determine the equivalence point of the titration. In this case, we have a strong base and a strong acid.
(H₂SO₄, is considered strong, but the first deprotonation is weak)
2NaOH  +  H₂SO₄  →  Na₂SO₄  + 2H₂O
As we have 2 protons in the acid, we need 2 OH⁻ from the base to form 2 molecules of water.
In the equivalence point we know mmoles of base = mmoles of acid
Let's finish the excersise with the formula
25 mL . M NaOH = 28.2 mL  .  0.355M
M NaOH = (28.2 mL  .  0.355M) / 25 mL → 0.400
 
        
             
        
        
        
Answer:
Approximately  .
.
Explanation:
Note that both figures in the question come with four significant figures. Therefore, the answer should also be rounded to four significant figures. Intermediate results should have more significant figures than that. 
<h3>Formula mass of strontium hydroxide</h3>
Look up the relative atomic mass of  ,
,  , and
, and  on a modern periodic table. Keep at least four significant figures in each of these atomic mass data.
 on a modern periodic table. Keep at least four significant figures in each of these atomic mass data.
Calculate the formula mass of  :
:
 .
.
<h3>Number of moles of strontium hydroxide in the solution</h3>
 means that each mole of
 means that each mole of  formula units have a mass of
 formula units have a mass of  .
. 
The question states that there are  of
 of  in this solution.
 in this solution. 
How many moles of  formula units would that be?
 formula units would that be?
 .
.
<h3>Molarity of this strontium hydroxide solution</h3>
There are  of
 of  formula units in this
 formula units in this  solution. Convert the unit of volume to liter:
 solution. Convert the unit of volume to liter:
 .
.
The molarity of a solution measures its molar concentration. For this solution:
 .
.
(Rounded to four significant figures.)
 
        
             
        
        
        
Answer:
The sun'll likely absorb the radiation if it is close enough (Which it will never be)
Explanation: