Answer:
See explanation
Explanation:
If the spot in TLC is below the solvent front, it will be observed that the spot, instead of being separated by the solvent as expected, will just dissolve away in the solvent and zero actual separation of the mixture is achieved.
If the solute is dissolved away instead of being separated by the solvent, then the experiment fails because no actual separation of the mixture is achieved.
Hence, in TLC, the spot must be applied above the solvent front so that the capillary movement of the solvent through the plate can lead to the eventual separation of the components of the mixture since the various components of the mixture will travel at different speeds through the plate.
Also, if the solvent is above the spot, the solvent may evaporate selectively from the points above the spot while separation is ongoing.
Answer: varriable
Explanation:meaning one element, feature or factor able to change
<h3>
Answer:</h3>
- They show the elements of make up a compound
- They show the types of atoms that make up a molecule
- They show the number of each type of atom in a molecule
<h3>
Explanation:</h3>
To answer this question we need to know what is a compound.
- A compound is a substance that is made by two or more atoms of different elements that are chemically combined.
- A chemical formula of a compound is a formula that shows the elements that make up a compound and also the types of atoms that make up the molecule.
- Additionally, the chemical formula shows the number of each type of atom in a molecule.
- In this case, the chemical formula of a molecule of H₂O shows that it is made up of one hydrogen atom and two oxygen atoms.
Answer:
Acid solution
Explanation:
In acid-base titrations carried out in school and college labs, many of the older generation, well-informed teachers told their students that the acid solution should be taken in the burette.
Answer:
The correct options are:
1) Pure chemical substance
2) Element.
Explanation:
each of the term is explained below:
1) <u>Mixture: </u> Since tungsten is an element in periodic table thus it is not a mixture.
2) False by definition of mixture.
3) false by definition of mixture.
4) <u>Solution:</u> Tungsten in a filament is in solid form hence solution is incorrect.
5) Since it is given in the question itself that the sample is pure hence option 'E' is correct as chemical substance is a pure substance that has a homogeneous composition and the sample in the question is given as pure.
6) <u>Compound:</u> By definition of compound it is formed by mixing 2 or more elements but since tungsten is an element that occurs independently in nature hence it is not a compound.
7) Tungsten is a element in the periodic table with atomic number 74.
