Which is/are used in nuclear reactors to absorb neutrons?

A. heavy nuclei

B. critical mass

C. chain reactions

D. control rods

Answer:

(b) fully filled valence s orbitals

Explanation:

Electron configuration of Be: 1s22s2

2s2 is fully filled

Answer:

A. In the Presense of a base

Explanation:

Just took the test from Edgunuity

Phenolphthalein turns pink in color in the presence of a base. Therefore, option A is correct.

Phenolphthalein is a chemical compound that is often used as an acid-base indicator. It is colorless in acidic solutions and pink or red in basic solutions.

Phenolphthalein is often used in titrations to determine the endpoint of a reaction between an acid and a base. It can also be used as a laxative or in forensic investigations to test for the presence of blood.

Phenolphthalein has a chemical formula of C₂₀H₁₄O₄ and is synthesized by reacting phthalic anhydride with phenol in the presence of a strong acid catalyst. It is also used as a pH indicator. phenolphthalein has been found to have potential health benefits, such as reducing the risk of cancer, improving digestion, and reducing inflammation. Therefore, option A is correct.

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Answer:

Explanation:

\we must convert the mass of NaCl in grams into moles. We do this by dividing by the molecular weight of NaCl (58.4 g/mole). Then, we divide the number of moles by the total solution volume to get concentration. The NaCl solution is a 0.1 M solution.

Answer:

0.125

Explanation:

boom

Answer:

A I think

Explanation:

Answer:

Expensive and low storing capacity.

Explanation:

The storing of renewable energy is a big challenge for us because this renewable energy can't be stored for a long due to expensive and low storing capacity. There are two challenges about the storing of renewable energy is that the battery are very expensive and can store very less amount of energy which makes unable to store the renewable energy. The scientists should make a storing device which is not too much expensive and has more storage capacity.

Answer:

1.91 atm

Explanation:

Step 1: Calculate Henry's constant (k)

A gas has a solubility (C) of 2.45 g/L at a pressure (P) of 0.750 atm. These two variables are related to each other through Henry's law.

C = k × P

K = C/P

K = (2.45 g/L)/0.750 atm = 3.27 g/L.atm

Step 2: Calculate the pressure required to produce an aqueous solution containing 6.25 g/L of this gas at constant temperature.

We have C = 6.25 g/L and k = 3.27 g/L.atm. The required pressure is:

C = k × P

P = C/k

P = (6.25 g/L)/(3.27 g/L.atm) = 1.91 atm

Explanation:

Facilitar el movimiento y desplazamiento de objetos pesados reduciendo el rose del objeto contra el suelo, Obtener un movimiento circular por efecto de la fuerza de un liquido, en el caso de contadores, molinos, centrales hidroeléctricas y turbinas.

Transmitir el movimiento de un eje a otro como en el caso de las lavadoras, bicicletas y neveras. Reducir drásticamente el esfuerzo necesario para elevar y mover objetos, como en casos de pozos de agua y ascensores Transformar movimientos giratorios en otros movimientos o viceversa. ,

Answer:

Branched chain

Cycloalkane

Straight chain

Explanation:

Answer:

What is the question your asking?

Explanation:

All atoms of the same element have the same properties.

Answer:

1c

2b

3a

Explanation:

Step 1: Write the general expression to calculate the freezing point depression

The freezing point depression is a colligative property, that can be calculated using the following expression.

ΔT = i × Kc × b

where,

i: van 't Hoff factor (number of ion particles per formula unit)

Kc:  cryoscopic constant (Kc for water: 1.86 °C.Kg/mol)

b: molality (moles of solute per kilogram of solvent)

All the solution have the same Kc and the same b (1 mol/1 kg = 1 m), so ΔTf variation will depend on i

Step 2: Calculate the freezing point of the Na₃PO₄ solution

Na₃PO₄ has 4 ions (3 Na⁺ and 1 PO₄³⁻), so i = 4.

ΔT = i × Kc × b = 4 × 1.86 °C.Kg/mol × 1 mol/kg = 7.44 °C

T = 0°C - 7.44 °C = -7.44 °C

Step 3: Calculate the freezing point of the CuSO₄ solution

CuSO₄ has 2 ions (1 Cu²⁺ and 1 SO₄²⁻), so i = 2.

ΔT = i × Kc × b = 2 × 1.86 °C.Kg/mol × 1 mol/kg = 3.72 °C

T = 0°C - 3.72 °C = -3.72 °C

Step 4: Calculate the freezing point of the C₆H₁₂O₆ solution

C₆H₁₂O₆ is a nonelectrolyte (it doesn't ionize), so i = 1

ΔT = i × Kc × b = 1 × 1.86 °C.Kg/mol × 1 mol/kg = 1.86 °C

T = 0°C - 3.72 °C = -1.86 °C

Answer:

Number of moles =20

Number of molecules present = 20 multipled by avogadro's number.

Answer: Water is a much better conductor of heat than air. So when you are surrounded by water, energy can flow from your body (conduction of heat) much more quickly than it would if you were surrounded by air at the same temperature.

Answer:

Molarity = moles ÷ liters

to get moles of NaBr divide grams of NaBr by its molar mass (mass of Na + mass of Bromine)

Na = 22.989769

Br = 79.904

molar mass of NaBr = 102.893769

6.6g ÷ 102.893769 = 0.064143826 moles of NaBr

0.064143826 moles ÷ 0.60 liters = 0.1069 molar concentration or 11 %

Answer: proton and neutron

Explanation:

They both have the mass of 1

Answer:

The answer is C = 9.52

Explanation:

I took the test

The pOH of a solution that has a pH of 4.48 at 25°C is 9.52. Details about pH can be found below.

pH refers to the power of hydrogen in a substance while the pOH refers to the power of hydroxyll ions. The pH of a solution ranges from 0 - 14 indicating the strength of acidity and alkalinity.

The relationship between the pH and pOH in a solution is given as follows:

pH + pOH = 14

According to this question, a solution at 25 degrees celsius has a pH of 4.48. The pOH of the solution is calculated as follows:

4.48 + pOH = 14

pOH = 14 - 4.48

pOH = 9.52

Therefore, the pOH of a solution that has a pH of 4.48 at 25°C is 9.52.

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Answer:

7.23x10^23 atoms

Explanation:

1 mole = 6.023x10^23

1.20 mole = 6.023x10^23 x 1.2

                = 7.23x10^23 atoms

The atoms present in 1.20 moles of copper is 7.23 × [tex]10^{23}[/tex] atoms.

A chemical element is made up of atoms, which are the basic components of ordinary matter.

Calculation of atoms

Given data:

n = 1.20 moles.

It is known that.

1 mole = 6.023 × [tex]10^{23}[/tex]

So, 1.20 moles = 6.023 ×  [tex]10^{23}[/tex]  × 1.2 = 7.23 ×  [tex]10^{23}[/tex]  atoms.

Therefore, number of atoms in copper will be  7.23 ×  [tex]10^{23}[/tex] atoms.

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Answer:

It’s answer #2

Explanation:

I only know this because i just got it wrong

The correct structural formula for the acid that is poured into the beaker is CH₃COOH.

Acetic acid is also called ethanoic acid. It is form as a byproduct of fermentation. It forms vinegar. Vinegar is 4 to 6% acetic acid with water.

It is widely used in homes as cleaning agent, in cooking, washing etc.

Thus, the correct option is 2, CH₃COOH.

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Answer:

1 mole.

Explanation:

1.6x10^23 = NA = 1 mole of any substance.

Answer:

d and e

Explanation:

We have 5 solutions with different molar concentrations, that is, the quotient between the number of moles of solute and the liters of solution. This can be expressed as mol/L or M. The most dilute would be the one having the less number of moles of solute per liters of solution, that is, solution d or e, which have the same concentration. If we order them from the most diluted to the most concentrated, we get:

d = e < a < b < c

Answer:

The value becomes 0.0821 L-atm/K⁻¹-mol⁻¹.

Explanation:

The value of gas constant is 0.0821.

We know that, the ideal gas law is as follows :

[tex]PV=nRT\\\\R=\dfrac{PV}{nT}[/tex]

Where

P is pressure

V is volume

T is temperature

In order to use the Ideal Gas Constant of 0.0821, the units are follows :

Volume = Litre (L)

Pressure = atm

Amount = mol⁻¹

Temperature = K⁻¹

So, the value becomes 0.0821 L-atm/K⁻¹-mol⁻¹.

Answer:

E) the K+ ions are attracted to the partially positive hydrogen atoms of the water molecule. D) the K+ ions are attracted to the partially negative oxygen atoms of the water molecule. Water is a polar solvent and hexane (C6H14) is a nonpolar solvent. Which of the following correctly describes the solubility of the solute? A) weak electrolyte.

Explanation:

Answer:

I think the answer is C. D. And F.

Explanation:

I’m sorry if I’m wrong :(

Answer:

I think the answer is BCD and maybe F

Explanation:

Answer: Mass is converted to the energy binding a nucleus together.

Explanation: a p e x

Mass is converted to the energy binding a nucleus together cause a mass defect.Hence , Option (C) is correct.

The actual atomic mass is less than the predicted mass calculated by adding the masses of nucleons.

This additional mass is accounted for by binding energy that is released when a nucleus is formed.

When a nucleus is formed, some of the mass is converted to energy and this results in the mass defect.

Therefore, Mass is converted to the energy binding a nucleus together cause a mass defect. Hence , Option (C) is correct.

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Answer: There are 0.0129 moles of silver present in 1.4 grams of silver (Ag).

Explanation:

Given: Mass of silver = 1.4 g

Number of moles is the mass of substance divided by its molar mass.

As molar mass of silver is 107.86 g/mol. Therefore, moles of silver are calculated as follows.

[tex]No. of moles = \frac{mass}{molar mass}\\= \frac{1.4 g}{107.86 g/mol}\\= 0.0129 mol[/tex]

Thus, we can conclude that there are 0.0129 moles of silver present in 1.4 grams of silver (Ag).

Answer:

The correct answer is - 2770000 cm.

Explanation:

1 kilometer = 1000 meter

1 meter = 100 centimeter

1 kilometer = 100*1000 cm

1 km = 100000 cm.

then,

27.7 kilometers = 2.77 × 10^6 centimeters

So, 27.7 kilometers = 27.7 × 100000

= 2.77 × 106 or 2770000 centimeters.