Answer:
concave lens
Explanation:
it's concave lens because it diverges the ray/beam of light.
I believe they are called Energy Levels or Energy Orbitals.
Flammable gases are gases that have the tendency to <u>explode (burst into flames)</u> when they come in contact with the <u>appropriate quantities of air, oxygen, or any suitable oxidant.</u>
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Devices that mix air or oxygen with flammable gasses cannot be used unless approved by an <u>authorized or approved personnel.</u>
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- Examples of flammable gases are hydrocarbons such as <u>Propane, Acetylene</u>, e.t.c.
- Flammable gases are dangerous to humans and the environment and if they are not handled properly, can cause severe damages and even death.
- During the preparation and usage of flammable gases, safety precautions should be properly enforced such as the <u>wearing of appropriate safety gear and goggles</u>.
- Devices that mix air or oxygen with flammable gases cannot be used unless approved by an <u>authorized or approved personnel.</u>
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brainly.com/question/3702349
<u>Answer:</u> The molality of naphthalene solution is 0.499 m
<u>Explanation:</u>
Density is defined as the ratio of mass and volume of a substance.
......(1)
Given values:
Volume of carbon tetrachloride = 500 mL
Density of carbon tetrachloride = 1.60 g/mL
Putting values in equation 1, we get:

Molality is defined as the amount of solute expressed in the number of moles present per kilogram of solvent. The units of molarity are mol/kg. The formula used to calculate molarity:
.....(2)
Given values:
Given mass of naphthalene = 51.2 g
Molar mass of naphthalene = 128.17 g/mol
Mass of solvent = 800 g
Putting values in equation 2, we get:

Hence, the molality of naphthalene solution is 0.499 m
Mass number...use da textbook bra