Hello :) how to do this?

28g/ dm³

0.5 M

Explanation:

1dm³= 1000cm³

Let's convert the volume to cm³.

Volume of solution

= 200cm³

= (200÷1000) dm³

= 0.2 dm³

Concentration in g/dm³ means the amount of solute, KOH, in 1 dm³ of solution.

In 0.2 dm³, there is 5.6g of KOH.

Thus in 1 dm³, amount of KOH

= 5.6 ÷0.2

= 28g

Concentration in g/dm³ is 28g/dm³.

Molarity is a concentration unit. It is the number of moles of solvent in 1 L or 1dm³ of solution. Since we have already found the mass of KOH in 1dm³ of solution, we will use dm³.

1dm³ 28g of KOH

moles= mass ÷mr

Molecular mass of KOH

= 39 +16 +1

= 56

1dm³ 28 ÷56= 0.5 moles of KOH

Thus, concentration in molarity is 0.5M.

(Unit for molarity is M)

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.