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3 years ago

What happens to the density of a substance when it is heated? Explain your answer.

1 answer:

7 0

Heating a substance causes molecules to speed up and spread slightly further apart, occupying a larger volume that results in a decrease in density. Cooling a substance causes molecules to slow down and get slightly closer together, occupying a smaller volume that results in an increase in density.

From: www.middleschoolchemistry.com

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The number of atoms or molecules in a mole is known as the __________ constant.

AnnZ [28]

Answer: Avogrado's Constant

Explanation:

One mole of a substance is equal to 6.022 × 10²³ units of that substance (such as atoms, molecules, or ions). The number 6.022 × 10²³ is known as Avogadro's number or Avogadro's constant. The concept of the mole can be used to convert between mass and number of particles.

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2 years ago

Select the correct value for the indicated bond angle in each of the following compounds: O-S-O angle of SO2 F-B-F angle of BF3

Stels [109]

Answer:

(A) O-S-O bond angle of SO₂ molecule = 119°

(B) F-B-F bond angle of BF₃ molecule = 120°

(D) O-C-O bond angle of CO₂ molecule = 180°

(E) F-P-F bond angle of PF₃ molecule = 96.3°

(F) H-C-H bond angle of CH₄ molecule = 109.5°

Explanation:

Bond angle refers to the angle between two adjacent chemical bonds in a molecule. The bond angle is different for different molecular geometry.

The Valence shell electron pair repulsion theory predicts the molecular geometry and shape of the given molecule by the number of lone pairs on central atom and number of atoms bonded to central atom.

(A) SO₂ molecule

The number of atoms bonded to S = 2

Number of lone pairs on S = 1

Therefore, the shape of SO₂ molecule is bent and the O-S-O bond angle is 119°.

(B) BF₃ molecule

The number of atoms bonded to B = 3

Number of lone pairs on B = 0

Therefore, the shape of BF₃ molecule is trigonal planar and the F-B-F bond angle is 120°.

(C) SCl₂ molecule

The number of atoms bonded to S = 2

Number of lone pairs on S = 2

Therefore, the shape of SCl₂ molecule is bent and the Cl-S-Cl bond angle is 103°.

(D) CO₂ molecule

The number of atoms bonded to C = 2

Number of lone pairs on C = 0

Therefore, the shape of CO₂ molecule is linear and the O-C-O bond angle is 180°.

(E) PF₃ molecule

The number of atoms bonded to P = 3

Number of lone pairs on P = 1

Therefore, the shape of PF₃ molecule is trigonal pyramidal and the F-P-F bond angle is 96.3°.

(F) CH₄ molecule

The number of atoms bonded to C = 4

Number of lone pairs on C = 0

Therefore, the shape of CH₄ molecule is tetrahedral and the H-C-H bond angle is 109.5°.

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3 years ago

Litmus paper is made from water-soluble dyes which are extracted from lichens. This paper is used as an acid-base indicator. Whi

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Your answer is vinegar C)

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What are Saturn's rings made up of and where are they found?(write like a sentences or two if u can)

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Saturn's rings are made of ice and rock. These pieces vary in size. Some are as small as a grain of sand. Others are as large as a house. The rings of Saturn are the most extensive ring system of any planet in the Solar System. They consist of countless small particles, ranging in size from micrometers to meters, that orbit around Saturn. They are found around the planet

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2 years ago

Which concept describes the formation of four equivalent, single, covalent bonds by carbon in its compounds that resembles metha

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Carbon is special and unique because it is able to form different compounds with a lot of elements, including itself. When it bonds with itself, this is possible because of the concept of hybridization. It is the mixing of atomic orbitals into a new hybrid orbital. In this case, methane is formed through the sp³ hybridization.

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3 years ago