Answer:

Explanation:
The formula for molality is:

There are 0.210 moles of KBr and 0.075 kilograms of pure water.

Substitute the values into the formula.

Divide.

The molality is <u>2.8 moles per kilogram</u>
So they can tell what exact species it is.
The correct option is C.
A Lewis dot diagram is a representation of the valence electron of an atom, which uses dot around the symbol of the atom. Chlorine has seven electrons in its outermost shell, these seven electrons are arranged in form of dot around the atom of chlorine. If you count the number of dot given in option C, you will notice that they are seven.
OK, so to answer this question, you will simply use the molality equation which is as follows:
<span>M1V1 = M2V2
In the givens you have:
M1 = 2M
V1 is the unknown
M2 = 0.4M
V2 = 100 ml
</span>plug in the givens in the above equation:
<span>2 x V1 = 0.4 x 100
</span>therefore:
V1 = 20 ml
Based on this: you should take 20 ml of the 2 M solution and make volume exactly 100 ml in a volumetric flask by diluting in water.
Answer:
answer is b
use pv=nRT
p directly proportional to moles(n)
p1/p2=n1/n2
p/p2=n/2n
p2=2p