Answer: It is important to wet the filter paper in the Buchner funnel first with cold re crystallization solvent before the re crystallization mixture being filtered to minimize gaps around the edges of the filter paper which can prevent mechanical impurities from passing through. This gives better filtration where most impurities can be filtered. Furthermore, it provides good vacuum.
Answer:

Explanation:
In this case, we can start with the <u>formula of Platinum (II) Chloride</u>. The cation is the atom at the left of the name (in this case
) and the anion is the atom at the right of the name (in this case
). With this in mind, the <u>formula would be</u>
.
Now, if we used <u>metallic copper</u> we have to put in the reaction only the <u>copper atom symbol</u>
. So, we have as reagents:

The question now is: <u>What would be the products?</u> To answer this, we have to remember <u>"single displacement reactions"</u>. With a general reaction:

With this in mind, the reaction would be:

I hope it helps!
Answer:
Thus,there are 0.2 mole in 8 g of calcium.
Answer: Pigment.
Explanation: Our hair color is determined by two types of pigment, Eumelanins, and Pheomelanins. Which together produces all the natural hair colors we see every day with other people.