Blue litmus paper turns red in the presence of an acid. Therefore, it can be assumed that the substance in the beaker is an acid.
Acids have a pH level of less than 7. Consequently, it can be assumed that the substance has a pH level less than 7.
Answer:
True
Explanation:
The first artificial use of a PGR was to stimulate the production of flowers on pineapple plants. They are now used widely in agriculture. Plant hormones are also used in turf management to reduce the need to mow, to suppress seedheads, and to suppress other types of grass.
Answer:- 
molecules.
Solution:- The grams of tetrabromomethane are given and it asks to calculate the number of molecules.
It is a two step unit conversion problem. In the first step, grams are converted to moles on dividing the grams by molar mass.
In second step, the moles are converted to molecules on multiplying by Avogadro number.
Molar mass of 
= 12+4(79.9) = 331.6 g per mol
let's make the set up using dimensional analysis:
= molecules
So, there will be molecules in 250 grams of .
<u>Answer</u>:
The inner walls of a vacuum flask have a silver coating to reduce heat loss by radiation.
<u>Explanation</u>:
The vacuum flask has an inner silver lining to prevent the transfer of heat by radiation. Radiation is a process where the emission or transformation of energy happens in the form of wave or the particles through the material medium.
Vacuum flask being working as thermal insulator helps in maintaining the substance its actual temperature for a long time. The silver lining acts as a reflector .It prevents the heat radiation to released out of the flask.
