That statement is true
it was easy to organize 'all' the elements in a group of threes because back then they only knew about 15 - 20 elements
hope this helps
<u>Answer:</u> The molality of solution is 0.740 m.
<u>Explanation:</u>
To calculate the mass of solvent (water), we use the equation:

Volume of water = 750 mL
Density of water = 1 g/mL
Putting values in above equation, we get:

To calculate the molality of solution, we use the equation:

Where,
= Given mass of solute
= 100.0 g
= Molar mass of solute
= 180 g/mol
= Mass of solvent (water) = 750 g
Putting values in above equation, we get:

Hence, the molality of solution is 0.740 m.
Answer:
HCO₂
Explanation:
From the information given:
The mass of the elements are:
Carbon C = 26.7 g; Hydrogen H = 2.24 g Oxygen O = 71.1 g
To determine the empirical formula;
First thing is to find the numbers of moles of each atom.
For Carbon:

For Hydrogen:

For Oxygen:

Now; we use the smallest no of moles to divide the respective moles from above.
For carbon:

For Hydrogen:

For Oxygen:

Thus, the empirical formula is HCO₂
H• •Be• •H --> H:Be:H
Since there are 4 valence electrons in total, Beryllium has 2 and Hydrogen has 2. You would put the Be in the middle because there is only 1 of them.