Answer:
In 1827, Brown observed, using a microscope, that small particles ejected from pollen grains suspended in water executed a kind of continuous and jittery movement, this was named “Brownian motion”. ... This random movement of particles suspended in a fluid is now called after him.
Explanation:
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Answer: Option (b) is the correct answer.
Explanation:
A covalent compound is defined as the compound in which sharing of electrons take place between the combining atoms. Generally, when two or more non-metals chemically combine together the it will lead to the formation of a covalent compound.
For example, 
and HCl is also a covalent compound.
And, a compound in which transfer of electrons occur between the combining atoms is known as an ionic compound. Whenever, a metal chemically combines with a non-metal then it will always lead to the formation of an ionic compound.
For example, KI is an ionic compound.
Thus, we can conclude that and HCl are the two substances which are covalent compounds.
A cell is a microscopic living organism which is the smallest part of an organism such as a plant or animal.
Answer:
It will lead to overestimation of the percent recovery
Explanation:
The percent recovery refers to the percentage of the pure compound recovered after a chemical process. It is a ratio of the pure compound recovered to the original substance multiplied by 100%.
If the sample was incompletely dried and the recrystallization solvent is still present, the percent recovery will be overestimated and we will have a value that is greater than the accurate percent recovery due to solvent impurities present.
