How many grams of potassium phosphate would be needed to make 25.0ml of a 0.75m solution?

Answer : The mass of potassium phosphate needed will be 3.98 grams.

Explanation : Given,

Molarity of potassium phosphate = 0.75 M = 0.75 mole/L

Molar mass of potassium phosphate = 212.27 g/mole

Volume of solution = 25.0 mL = 0.025 L    (conversion used : 1 L = 1000 mL)

Molarity : It is defined as the number of moles of solute present in one liter of solution.

In this problem solute is, potassium phosphate.

Formula used :

Now put all the given values in this formula, we get:

Therefore, the mass of potassium phosphate needed will be 3.98 grams.

the answer

explanation:

the capillary tube was too close to the bottom of the beaker.

the ruler may have moved.

water got into the capillary tube.

the temperature was not allowed to equilibrate in the 2-4 minutes.

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.