Answer:
Intermolecular forces are much weaker than the strong covalent bonds within the molecules. ... Very little energy is needed to overcome the intermolecular forces, so simple molecular substances usually have low melting and boiling points. They are often liquids or gases at room temperature
Answer:
US. With an installed capacity of 3,639MW in 2018, the US is the leading producer of geothermal energy across the world, producing 16.7 billion kilowatt hours (kWh) of geothermal energy throughout the year. ...
Indonesia. ...
Philippines. ...
Turkey. ...
New Zealand. ...
Mexico. ...
Italy. ...
Iceland.
The fish is the first organism that would be tested and measured for DDT as it pass on the DDT to the upward trophic level in food chain. After that predators will be checked for DDT concentration.
Explanation:
DDT level in the organism gets increase as it moves upward in the trophic level.
Toxins as DDT gets incorporated to fats and tissues of the organism. It gets soluble in fats.
The highest concentration of DDT is observed in tertiary consumers as carnivore.
It can be seen that DDT concentration is more in producers than primary consumers. With the process of biomagnification the concentration of DDT increases at successive levels.
In aquatic food chain pesticides or heavy metals are consumed by aquatic organsims which are consumed by large birds and human. The DDT level will be checked in fish then birds and humans.
Answer:
A. the ration is 2 to 3, 2Al + 3H2SO4 has the same balance as 18Al + 3H2SO4
2/3 = 18/27
B. Doesn't need an explanation other than the work you did to balance it.
This technique can be used to make pure crystals of a soluble salt.
The burette is filled with hydrochloric acid.
A known quantity of alkali (say 50 cm3 sodium hydroxide)
is released from a pipette into the conical flask.
The tap on the burette is turned open to allow
the acid to be added drop by drop into the alkali.
The alkali contains an indicator (phenolphthalein)
which is pink in an alkali and colorless in an <span>acid.
</span>
When enough acid has been added to neutralize
the alkali, the indicator changes from
pink to colorless. This is the end point of the titration.
The titration<span> can be repeated using the </span><span>same amounts
</span><span>of </span>acid<span> and </span>alkali<span> but </span>without<span> the </span>indicator.
<span>Pure salt</span> crystals<span> which are </span>free<span> from </span><span>indicator
</span><span>can then be crystallized </span><span> from the </span>neutral<span> solution.</span>
