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3 years ago

What is first and second element of the periodic table?

2 answers:

7 0

The elements on the periodic table are listed in increasing atomic number.

Hydrogen is the first element, and has an A.N. of 1. Also, its very interesting how it doesn't need 8 valence electrons to be stable.

The second element is Helium, which has an A.N (atomic number) of two.

WINSTONCH [101]3 years ago

6 0

Hydrogen= First element,H

Helium=Second Element,He

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Which of the following is the simplest ketone used as an organic solvent?

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Answer: Option (d) is the correct answer.

Explanation:

A ketone is an organic functional group that contains a carbon and oxygen atom bonded together through a double bond, that is, C=O.

For example, acetone $CH_{3}-CO-CH_{3}$ is a ketone.

Whereas a hydrocodone is a drug which is used to relieve from moderate to sever pain.It is mostly combined with other drugs and resulting in a chemical formula $C_{18}H_{21}NO_{3}.C_{4}H_{6}O_{6}$ .

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A menthone is also an organic compound with chemical formula $C_{10}H_{18}O$ .

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3 years ago

What is the difference between a physical and chemical change? (Use words reactants, products, atoms and molecules.)

jeka94

Answer:

A physical change, such as a state change or dissolving, does not create a new substance, but a chemical change does. In a chemical reaction, the atoms and molecules that interact with each other are called reactants. In a chemical reaction, the atoms and molecules produced by the reaction are called products.

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2 years ago

A gas sample occupies 350.0 mL at 546 mm Hg. What volume does the gas occupy at 652 mm Hg?

leva [86]

Answer:

293.1 mL.

Explanation:

Boyle's law states that: at a constant temperature the pressure of a given mass of an ideal gas is inversely proportional to its volume.

It can be expressed as: P₁V₁ = P₂V₂,

P₁ = 546.0 mm Hg, V₁ = 350.0 mL.

P₂ = 652.0 mm Hg, V₂ = ??? mL.

∴ V₂ = (P₁V₁)/(P₂) = (546.0 mm Hg)(350.0 mL) / (652.0 mm Hg) = 293.1 mL.

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3 years ago