Answer:
Coal is classified as a nonrenewable energy source because it takes millions of years to form. Coal contains the energy stored by plants that lived hundreds of millions of years ago in swampy forests.
<span>Minerals are solid substances that occur naturally. They can be made from a single element (like gold or copper) or from a combination of elements.</span>
Answer:
Via covalent bonds
Explanation:
Atoms in molecules are bonded together via covalent bonds. Covalent bonds are bonds that are formed by sharing of the valence electrons between two atoms.
The atoms can be of the same kind or of different kinds.
- In most molecules, the two atoms are connected by sharing of their valence electrons.
- This way, each atom can attain stability by becoming isoelectric with the nearest noble gas.
- Some molecules are monoatomic, some are polyatomic.
Answer:
Both b and d can be correct
Explanation:
Generally, diffusion does not require energy (<em>making option a wrong</em>) because it is the movement of particles from a region of high concentration to a region of low concentration hence diffusion moves particles in the direction of a concentration gradient. An example of this is the passive transport (for instance, uptake of glucose by a liver cell).
However, in some cases, when diffusion is against the concentration gradient (i.e when particles move from a region of low concentration to a region of high concentration), diffusion will require energy in a case like this (<em>making option c wrong</em>). An example of this is active transport (transport of protein called sodium-potassium pump which involves pumping of potassium into the cell and sodium out of the cell).
The explanation above shows that diffusion can require energy to move particles (in or out) of the cell through the cell membrane.
Answer:
1) Pure water can conduct electricity because a small proportion of its molecules dissociate into ions . The two ions formed in water are, hydrogen ions, H +, and hydroxide ions, OH -.
2) dynamic equilibrium
Explanation:
I hope this helps!