this is a dilution question where a certain volume is taken from a more concentrated solution and diluted to make a solution with a lower concentration.
the dilution forumla is as follows
c1v1 = c2v2
where c1 is concentration and v1 is volume of the more concetrated solution
c2 is concentration and v2 is volume of the diluted solution
substituting the values in the equation
18.0 M x V = 0.126 M x 16.5 L
V = 0.1155 L
volume of 115.5 mL is taken from the 18.0 M solution and diluted upto 16.5 L solution.
D
because they are elements in the same group as strontium
Molecular equation:
<span>Na2CO3 (aq) + CaCl2 (aq) → CaCO3 (s) + 2 NaCl (aq) </span>
<span>Ionic equation: </span>
<span>2 Na⁺ (aq) + CO3²⁻ (aq) + Ca²⁺ (aq) + 2 Cl⁻ (aq) → CaCO3 (s) + 2 Na⁺ (aq) + 2 Cl⁻ (aq) </span>
<span>Net ionic equation: </span>
<span>CO3²⁻ (aq) + Ca²⁺ (aq) → CaCO3 (s)</span>
Negatively-charged ions are anions, formed from nonmetallic elements like OXYGEN and sulfur.
Photosynthesis, hope this helps