Answer:
the properties of three undiscovered elements is the correct answer.
Explanation:
After he completed his work Mendeleev predicted the properties of the undiscovered elements.
In the year 1871, Dmitri Mendeleev predicted the detailed existence and the properties of the three elements that are undiscovered and he gained tremendous fame.
He left the gap in the table to put the elements which are not identified at that time and by glancing at the physical and chemical properties of an element next to the gap, Mendeleev could predict the properties of the not discovered elements.
Answer:
Weather and erosion.
Explanation:
In Geography, weathering is the process of breaking down of rocks, minerals and soil as a result of contact with water, earth's atmosphere, acid, ice, plants and animals. The breaking up of the rocks by weathering weakens it and makes it susceptible to erosion.
Erosion in geography is the movement of rocks and sediments to another place by water, wind and ice.
For instance, In many parts of the Cross Timbers and Prairies ecoregion, the Brazos river has formed tall, steep cliffs in the rock along its banks through the processes of weathering and erosion.
Answer:
pH = 12.52
Explanation:
Given that,
The [H+] concentration is 
.
We need to find its pH.
We know that, the definition of pH is as follows :
![pH=-log[H^+]](https://tex.z-dn.net/?f=pH%3D-log%5BH%5E%2B%5D)
Put all the values,
![pH=-log[3\times 10^{-13}]\\\\pH=12.52](https://tex.z-dn.net/?f=pH%3D-log%5B3%5Ctimes%2010%5E%7B-13%7D%5D%5C%5C%5C%5CpH%3D12.52)
So, the pH is 12.52.
