Answer: An existing theory is modified so that it can explain both the old and new observations.
Explanation:
Answer:
It basically messes up the results
Explanation:
Pen ink consists of resins, pigments and other colouring dyes dissolved in appropriate solvents like propylene glycol, propyl alcohol and some other ethers. If the ball point pen is used to mark on the chromatography paper then these pigments will also move along with the solvent and interfere with the spots of our analyte.
If you use a ball point pen when doing a chromatogram, then the ink would separate as it is a mixture and run down the paper.
Graphite, or pencil lead however, is not an organic material and therefore will not be affected by common organic solvents used for thin-layer chromatography. Pen ink on the other hand will be readily absorbed by the solvent and will move up the plate.
Answer:
STP in chemistry is the abbreviation for Standard Temperature and Pressure. STP most commonly is used when performing calculations on gases, such as gas density. The standard temperature is 273 K (0° Celsius or 32° Fahrenheit) and the standard pressure is 1 atm pressure.
Answer:

Explanation:
Hello,
In this case, since the undergoing chemical reaction is:

The corresponding moles of carbon dioxide occupying 40.0 mL (0.0400 L) are computed by using the ideal gas equation at 273.15 K and 1.00 atm (STP) as follows:

Then, since the mole ratio between carbon dioxide and calcium carbonate is 1:1 and the molar mass of the reactant is 100 g/mol, the mass that yields such volume turns out:

Regards.