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.
Answer:
B. a change in their state or substance
Explanation:
A change of state consists of a physical process in which the structure of the substance changes, its appearance. EXAMPLE: in the merger, the solid state becomes liquid, changes the rearrangement of particles from being highly compacted to being less compact.
Liter. The measure for volume is m^3
H₃PO₄ is stronger acid than H₃AsO₄.
H₃PO₄ is the stronger acid because PO₄is more electronegative than Se so PO₄3- is more stable than AsO₄3-.
<h3>Acid definition</h3>
Any substance that tastes sour in water solution, turns blue litmus paper red, reacts with some metals to release hydrogen, reacts with bases to form salts, and stimulates chemical reactions is considered an acid (acid catalysis).
An acid is a chemical substance, typically a liquid, that contains hydrogen and can interact with other substances to form salts. Some acids react with other materials and burn or dissolve them.
Acids are frequently encountered in daily life. They exist naturally in foods, are found in cells and digestive systems, and are used in numerous regular chemical reactions. Strong acids that are frequently used include nitric acid, phosphoric acid, sulfuric acid, and hydrochloric acid.
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Answer:
D.
Explanation:
Inverse and proportional means as one goes up the other goes up or if one goes down the other goes down.
- Hope that helped! Please let me know if you need further explanation.