Answer:
D. It is converted into kinetic energy.
Explanation:
When a book is dropped from a desk to the floor, the potential energy of the book is converted to kinetic energy as it falls.
- Potential energy of a body is the energy due to the position of the body.
- At a particular height, the potential energy is maximum.
- A body with mass and moving with velocity will have kinetic energy
- As the book drops through the height, to conserve energy, the potential energy is converted to kinetic energy.
Answer:

Explanation:
Hello,
In this case, since the undergoing chemical reaction is:

The corresponding moles of carbon dioxide occupying 40.0 mL (0.0400 L) are computed by using the ideal gas equation at 273.15 K and 1.00 atm (STP) as follows:

Then, since the mole ratio between carbon dioxide and calcium carbonate is 1:1 and the molar mass of the reactant is 100 g/mol, the mass that yields such volume turns out:

Regards.
Covalent for the first one
Answer:
your answer is single replacement reaction or ay+b----> by+a
Air is a mixture of approximately 80% nitrogen, 20% oxygen and a small amount of many other gases.