efficiency= [useful energy transferred ÷ total energy supply]×100%
So, [5500÷10000]×100%=0.55×100
=55%
A cold acetic acid solution is used to wash the residue of
the reagent in preparation of an aldol condensation product after vacuum
filtration. The main reason in washing
with the acetic acid rinse is to neutralize any sodium hydroxide.
The correct answer would be B. It is the compound Na2S that forms an ionic bond from the given ion above. From the choices, it is the only compound that exist and is available. Metals cannot react with another metal as well as nonmetal to nonmetal.
A campfire being lighted and plants converting carbon-dioxide and water into glucose and oxygen are both forms of chemical change.
Therefore, the answer is:
B. Both are examples of chemical change.
Answer:
Option A; ITS SURFACE IS COOLER THAN THE SURFACE OF THE SUN.
Explanation:
A red supergiant star is a larger and brighter type of red giant star. Red supergiants are often variable stars and are between 200 to 2,000 times bigger than the Sun. Example is Betelgeuse.
Betelgeuse is one of the largest known stars, it has a diameter of about 700 times the size of the Sun or 600 million miles, it emits almost 7,500 times as much energy as the Sun, it has a rather low surface temperature (6000F compared to the Sun's 10,000F); this means that it has a more cooler surface than the Sun's surface.
This low temperature also means that the star will appear orange-red in color, and the combination of size and temperature makes it a kind of star called a red super giant.
Although, all the statements above are correct, the only one that can be inferred from the red color of Betelgeuse is that ITS SURFACE IS COOLER THAN THE SURFACE OF THE SUN.
