Answer:
12.78 or 12.80 mostly like 12.78
Explanation:
Answer:
Here's what I get
Explanation:
You want to dilute the original solution by a factor of 25 in two steps, so you could dilute it by a factor of 5 in the first step, then dilute the new solution by another factor of 5.
A. First dilution
Use a 10 mL pipet to transfer 10 mL of the original solution to a 50 mL volumetric flask. Make up to the mark with distilled water. Shake well to mix.
Use the dilution formula to calculate the new concentration.

B. Second dilution
Repeat Step 1, using the 0.003 970 mol·L⁻¹ solution.

3. Check:
Compare the final concentration with the original

Answer: D. Physical change
Explanation:
Phase changes are physical changes.
Answer:
Metallic character decreases, and electronegativity increases.
Explanation:
Hello!
In this case, according to the organization of the periodic table, we can see that from left to right, the electronegativity increases as nonmetals are able to attract electrons more easily than metals.
Moreover, in contrast to the previous periodic trend, the metallic character decreases from left to right because the elements tend to decrease the capacity to lose electrons and consequently start attracting them.
Thus, the answer would be: "Metallic character decreases, and electronegativity increases".
Best regards!