Answer:
a chemical change is usually an irreversible chemical reaction. an example of this is rusting.
a physical change is usually visible while a chemical change isn't. also, a chemical change is irreversible while a physical change is.
Explanation:
Answer: These results show that the body regulates its salt and water balance not only by releasing excess sodium in urine, but by actively retaining or releasing water in urine.
Explanation:
Answer:
The wavelength of a sound is the distance between adjacent identical parts of a wave. The frequency is the same as that of the source and is the number of waves that pass a point per unit of time.
Answer:
B. CA, 14
Explanation:
Atoms of elements contain small particles known as electrons, neutrons, and protons. The nucleus of an atom is made up of neutrons and protons which are at the center of the atom. Electrons on the other hand surrounds the nucleus. Electron has negative charge while proton has a positive charge. The number of neutrons is equivalent to the number of protons . In addition, the number of protons is equal to mass number minus the number of electrons.
For the compound , it can be broken down into and . Its ion has a mass of 34 and 18 electrons which means it has already lost 2 electrons.
Therefore:
For the given element, the number of electrons is 18+2 = 20 electrons.
The number of protons = 34 - 20 = 14.
And the number of neutrons is 14.
Only option B has the correct answer.