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3 years ago

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Iron has a density of 7.9 g/cm3. The volume of a regular cylinder is V =πr2h. An iron cylinder has a height of 3.00 m and a mass

of 2.00 kg. Using the value 3.1416 for the constant π, the radius in cm of the iron cylinder is?

1 answer:

Sedaia [141]3 years ago

6 0

Hfhsnebrjicjcbdnd hope this helps

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A solution containing 20.0 g of an unknown liquid and 110.0 g water has a freezing point of .32 °C. Given Kf 1.86°C/m for water,

hjlf

Answer:

A. 256

Explanation:

In a solution where a liquid is the sovent, we'll use the van't Hoff factor, which is the ratio between the number of moles of particles produced in solution and the number of moles of solute dissolved, will be equal to 1.

ΔTemp.f = i * Kf * b

where,

ΔTemp.f = the freezing-point depression;

i = the van't Hoff factor

Kf = the cryoscopic constant of the solvent;

b = the molality of the solution.

So the freezing-point depression by definition is the difference between the the freezing point of the pure solvent and the freesing point of the solution.

Mathematically,

ΔTemp.f = Temp.f° - Temp.f

where,

Temp.f° = the freezing point of the pure solvent.

Temp.f = the freezin point of the solution.

Freezing point of pure water = 0°C

ΔTemp.f = 0 - (-1.32)

= 1.32°C

i = 1,

Kf = 1.86 °Ckg/mol

Solving for the molality, b = ΔTemp.f/( i * Kf)

= 1.32/(1*1.86)

= 0.71 mol/kg

Converting from mol/kg to mol/g,

0.71 mol/kg * 1kg/1000g

= 0.00071 mol/g.

Mass of solvent = 110g

Number of moles = mass * molality

= 0.00071 * 110

= 0.078 mol.

To calculate molar mass,

Molar mass (g/mol) = mass/number of moles

Mass of solute (liquid) = 20g

Molar mass = 20/0.078

= 256.2 g/mol

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3 years ago

How does the lens of a light microscope work?

ohaa [14]

D. the reflection of each concave lens makes the object appear larger

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3 years ago

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Which of the following represents new land formed beneath the plates from divergent boundaries?

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Answer:

Mid ocean ridge.

Explanation:

(it is an underwater mountain range, formed by plate tectonics.)

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3 years ago

How much did you pay if an item with an original price of $43.43 has a 20% discount?

Zigmanuir [339]

Answer:

Original price: $

54.29

Discount percentage:

20

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Explanation:

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2 years ago

calculate the standard potential arising from the reaction in which NADH is oxidized to NAD and the corresponding biological sta

melisa1 [442]

Answer:

-219.99kJ

Explanation:

The acronym '' NADH'' simply stands for what is known as coenzyme 1 with full meaning of Nicotinamide Adenine Dinucleotide Hydride. This substance is useful in the production of energy. The oxidation reaction of NADH causes it to produce NADP⁺ and the oxygen produces water when it is in the reduction process. The balanced equation for the oxidation reaction is given below as:

NADPH ---------------------------------------------------------------------> NADP⁺H⁺ + 2e⁻.

Also, the balanced equation for the reduction reaction is given below as:

$\frac{1}{2}$ O₂ + 2H⁺ + 2e⁻ --------------------------------------------------------------> H₂O.

It can be shown from the above REDOX reaction that the total number of electrons getting transferred is 2.

The Gibbs energy = -nFE. where n = 2, F = faraday's constant = 96485.3329 C and E = overall cell potential.

The overall cell potential = E[ reduction reaction] - E[oxidation reaction] = 0.82 - (- 0.32 ) = 1.14 V.

Hence, the Gibbs energy = - 2 × 96485.3329 × 1.14 = -219.99kJ

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3 years ago