Answer:
3.14 grams of ammonium thiocyanate must be used to react completely with 6.5 g barium hydroxide octahydrate.
Explanation:

The balance chemical equation is :

Mass of barium hydroxide octahydrate = 6.5 g
Moles of barium hydroxide octahydrate = 
According to reaction, 2 moles of ammonium thiocyanate reacts with1 mole of barium hydroxide octahydrate. The 0.020635 moles of barium hydroxide octahydrate will react with:

Mass of 0.04127 moles of ammonium thiocyanate;

3.14 grams of ammonium thiocyanate must be used to react completely with 6.5 g barium hydroxide octahydrate
The correct answers are A and C.
Answer:
C₇H₁₆ + 32CoF₃ —> C₇F₁₆ + 16HF + 32CoF₂
Explanation:
C₇H₁₆ + CoF₃ —> C₇F₁₆ + HF + CoF₂
The above equation can be balance as illustrated below:
C₇H₁₆ + CoF₃ —> C₇F₁₆ + HF + CoF₂
There are 16 atoms of H on the left side and 1 atom on the right side. It can be balance by writing 16 before HF as shown below:
C₇H₁₆ + CoF₃ —> C₇F₁₆ + 16HF + CoF₂
There are 3 atoms of F on the left side and a total of 34 atoms on the right side. It can be balance by writing 32 before CoF₃ and 32 before CoF₂ as shown below:
C₇H₁₆ + 32CoF₃ —> C₇F₁₆ + 16HF + 32CoF₂
Now, the equation is balanced.
Answer: The molarity of this solution is 0.159 M.
Explanation:
Given: Mass of solute = 16.3 g
Volume = 1.75 L
Number of moles is defined as the mass of substance divided by its molar mass.
Hence, moles of NaCl (molar mass = 58.44 g/mol) ar calculated as follows.

Molarity is the number of moles of a substance present in a liter of solution.
So, molarity of the given solution is calculated as follows.

Thus, we can conclude that the molarity of this solution is 0.159 M.