We will get the molality from this formula:
Molality = no.of moles of solute / Kg of solvent
So first we need the no.of moles of KNO3 = the mass of KNO3 / molar mass of KNO3
no.of moles of KNO3 = 175 / 101.01 = 1.73 mol
By substitution in the molality formula:
∴ molality = 1.73 / (750/1000) = 2.3 Molal
Answer:
Cohesion
Explanation:
Cohesion tension theory of water movement up the tree vessels
Cohesion is the term used to describe the binding forces present in water molecules through hydrogen bonds as such the water molecules have considerable tensile strenghth allowing them to be pulled up into the leaves of plants through the tree vessels without breakage as longitutudinal stress are placed on the water as it is pulled up
Answer:
Atoms gain or lose electrons
Explanation:
Photons can sometimes break apart molecules
Answer:
- Please, find the drawing in the picture attached.
Explanation:
A simple model or drawing of the structure of an atom may be performed showing the electrons on the different energy levels (shells), plus the nucleons (protons and neutrons).
Then, you need the information on:
- number of protons (atomic number)
- electron configuration
- number of neutrons
The first step is to find the atomic number of the atom. You find that information in the periodic table, where the elements are show with their chemical symbol.
The chemical symbol of sodium is Na. It is located in the group (colum) 1 and period (raw) 3. There you find that the atomic number is 11. Hence your drawing must show 11 protons.
Since the atom is neutral, the number of electrons is also 11. So, you must place the electrons in the following energy levels or shells:
Main energy level shell number of electrons
n = 1 K 2 (this is the maximum in this level)
n= 2 L 8 (this is the maximun in this level)
n= 3 M 1 (the maximum in this level is 18)
Now that you have the number of protons and the location of the electrons, you must determine the number of neutrons.
In the periodict table you will also find the atomic mass of the elements. The atomic mass of sodium is 22.990 amu. That means that most sodium atoms have mass number (number of protons plus neutrons) 23. Some isotopes will have less neutrons, but you can draw your model using the most typical isotope with 23 nucleons. This means, that the number of neutrons is 23 nucleons - 11 protons = 12 neutrons.