Answer: Compound
Explanation:
Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Copper 
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: water 

Thus as it give that the red sample on being heated, a gas is released and a blue powder is left after the heating. Thus the given sample is a compound.
The downward pressure on the hg in barometer is <u>the same as</u> the pressure of the atmosphere.
The atmospheric pressure or barometric pressure is the force exerted by the air in the atmosphere on the earth's surface.
The atmospheric pressure is caused by air molecules colliding with the surface. The atmospheric pressure at sea level is about 101 kPa and at the cruising altitude of a passenger plane it is 27 kPa.
The atmospheric pressure decrease as the height of a surface above ground level increases.
<h3>What is a barometer?</h3>
A barometer is a measuring instrument used to measure the atmospheric pressure or weight of the air, which is useful for making weather predictions.
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Answer:
gallium
Explanation:
it is the old melting in a hot cup of coffee spoon
Energy is released when an electron transitions from one energy level to another. In contrast, the same amount of energy is needed to carry out the process, the other way around, from the bottom elevation to the upper one.
What occurs when an electron transitions from one energy level to another?
- The energy of the electron drops when it changes levels, and the atom releases photons. The electron emits a photon when it transitions from a greater to a lower energy level. The energy emitted is precisely the energy that is lost when an electron moves to a level with less energy.
- An atom's electrons have negative energy. The electron must be given energy in order to be removed from the hydrogen atom, as shown by the negative sign. The quantity of energy in the atom will rise by supplying the electron with energy. Similar to how a ball on Earth chooses to rest in valleys rather than hills, the electron wants to spend the majority of its time at a lower energy level.
- For a brief period of time, the electron remains in an excited state. The energy required to bring the electron to its lower-energy state will be released when the electron transitions between excited and unexcited states.
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Because you are never 100% precise during the work, so it's best and most accurate answer is always the average of more trials. basically the more you do, the more accurate the answer shall be