Answer: iron (oxides of iron)
Explanation: manganese nodules usually contain layers of iron and manganese oxides in a concentric arrangement and are called polymetallic nodules.
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:
<h3>The answer is option C</h3>
Explanation:
The mass of a substance when given the density and volume can be found by using the formula
<h3>mass = Density × volume</h3>
From the question
volume of liquid = 15 mL
density = 2.5 g/mL
We have
mass = 15 × 2.5
We have the final answer as
<h3>37.5 g</h3>
Hope this helps you
Answer:
Carbonation. When you think of carbonation, think carbon
Oxidation. Oxygen causes oxidation.
Hydration. This isn't the hydration used in your body, but it's similar.
Explanation: