Answer:
Number of protons = 82
Explanation:
Given data:
Atomic number of Pb = 82
Mass number of Pb-207 = 207
Number of protons = ?
Solution:
An atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.
All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. The sum of neutrons and protons is the mass number of an atom while the number of protons are number of electrons is the atomic number of an atom.
Atomic number of Pb = number of protons or electrons
82 = number of protons or electrons
Mass number = Number of protons + number of neutron
207 = 82 + number of neutron
Number of neutrons = 207 - 82
Number of neutrons = 125
Answer:
1 True
2. True
3. True
4. True
5. False
Explanation:
1. Hypochlorous acid (HOCl) is a weak acid that forms when chlorine dissolves in water, and is partially dissociated, forming hypochlorite. HOCl is considered a strong oxidizing agent responsible for the killing action of germs in chlorine solutions.
2. Acetic acid is also known as ethanoic acid. It has a distinctive sour taste and pungent smell, and is generally considered a weak acid. in a concentrated form, acetic acid can be corrosive.
3/4 . Methylene chloride is an organochloride compound with the formula CH2Cl2. It is a colorless, volatile liquid with a moderately sweet aroma is widely used as a solvent. It is normally stable, non-flammable and non-explosive when mixed with air at temperatures below 100 °C, but its vapor is flammable only when present in relatively high concentrations of about 14% to 22% in air. Research shows that it is very much possibly carcinogenic, and it has been linked to cancer of the lungs, liver, pancreas, breast cancer and salivary gland cancer in laboratory animals.
5. Laboratory and medical waste are not to be disposed in the trash with regular wastes, as they are potentially toxic. Special disposal methods and agencies exists to take away such wastes.
Atomic mass Sodium ( Na ) = 22.98 u.m.a
22.98 g ----------------- 6.02x10²³ atoms
175 g ------------------- ?? atoms
175 x ( 6.02x10²³) / 22.98 =
4.58x10²⁴ atoms of Na
hope this helps!
