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3 years ago

What is a characteristic that can be observed or measured without changing the chemical makeup of a substance? *

Chemistry

1 answer:

olga55 [171]3 years ago

4 0

The correct answer is B

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What are alleles A the decoders of the dna message B two forms of single genes c the basic unit inheritance d a measurable

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I think the answer is D

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3 years ago

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What type of bond is present between two atoms of tungsten in a light bulb filament?

stiks02 [169]

Answer:

ionic bonding

Explanation:

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8 0

3 years ago

In the sixteenth century, the geocentric theory was a daim with substantial evidence. Which of the following best describes why

Ronch [10]

Answer:

The heliocentric theory was better supported by data explaining the rotation of the planets and other bodies in the solar system.

Explanation:

3 0

3 years ago

A chemist added an excess of sodium sulfate to a solution of a soluble barium compound to precipitate all of the barium ions as

grigory [225]

Answer:

259.497 mg, 58.84%

Explanation:

BaSO₄ → Ba²⁺ + SO₄²⁻

to calculate the mole of BaSO₄

mole BaSO₄ = mass given / molar mass = 403 mg / 233.38 g/mol = 1.7268 mol

comparing the mole ratio

1.7268 mol of BaSO₄ yields 1.7268 mol of Ba²⁺

403 mg BaSO₄ yields ( 1.7268 × 137.327 ) where 137.327 is the molar mass of Barium mol of Ba²⁺

441 mg BaSO₄ will yield ( 1.7268 × 137.327 × 441 mg ) / 403 mg = 259 .497 mg

mas percentage of the Barium compound = 259 .497 mg / 441 mg × 100 = 58.84%

8 0

3 years ago

2. Calculate the number-average molecular weight of a random poly (isobutylene-isoprene) copolymer in which the fraction of isob

Phoenix [80]

Answer : The number-average molecular weight is, 97500 g/mol

Explanation :

First we have to calculate the molecular weight of isobutylene and isoprene.

The molecular formula of isobutylene and isoprene is, $C_4H_8$ and $C_5H_8$

Molecular weight of $C_4H_8$ = 4(12 g//mol) + 8(1 g/mol) = 56 g/mol

Molecular weight of $C_5H_8$ = 5(12 g//mol) + 8(1 g/mol) = 68 g/mol

Now we have to calculate the average repeat molecular weight.

Average repeat molecular weight = $0.25\times (56g/mol)+(1-0.25)\times (68g/mol)$

Average repeat molecular weight = 65 g/mol

Now we have to calculate the number-average molecular weight.

Number-average molecular weight = Average repeat molecular weight × Degree of polymerization

Number-average molecular weight = (65 g/mol) × (1500)

Number-average molecular weight = 97500 g/mol

Thus, the number-average molecular weight is, 97500 g/mol

5 0

3 years ago