Potassium cyanide is a toxic substance, and the median lethal dose depends on the mass of the person or animal that ingests it. The median lethal dose of KCN for a person weighing 215 lb (97.5 kg ) is 8.84×10−3 mol .

What volume of a 0.0250 M KCN solution contains 8.84×10−3 mol of KCN?

Express the volume to three significant figures and include the appropriate units.

The total work produced by the steam engine needs to be calculated and given that the steam engine accepts heat during isothermal expansion at 250 °C and discards heat through isothermal compression at 25 °C.

The magnitude of the entropy change during the isothermal compression step is 750 J/K. The efficiency of the steam engine is 65% of the maximum attainable theoretical efficiency. Given that the efficiency of the steam engine is 65% of the maximum attainable theoretical efficiency.

Hence, the actual efficiency will be:

η_actual = η_max × 0.65Where,

η_max is the maximum attainable theoretical efficiency.

η_actual = 0.65 × η_maxNow,

the efficiency of a Carnot engine (η_Carnot) can be given as:η_Carnot = 1 - (T_cold / T_hot)Here, T_hot and T_cold are the temperatures of the hot and cold reservoirs respectively.

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Work is a measure of the energy transfer that occurs when an object is moved against a force. Work is defined as the product of the force applied to an object and the displacement of the object in the direction of the force. Hence the total work produced by the engine is 47,175 J.

1. Converting the temperatures from degrees Celsius to Kelvin.

T1 = 250 °C + 273.15 K = 523.15 K

T2 = 25 °C + 273.15 K = 298.15 K

2. The maximum attainable theoretical efficiency.

ηmax = 1 - T2 / T1 = 1 - 298.15 / 523.15 = 42.9%

3. The efficiency of the steam engine.

η = 0.65 * ηmax = 0.65 * 42.9% = 27.7%

4. The entropy change during the isothermal expansion step.

dS = 750 J/K

5. The total work produced by the engine.

W = η * (T1 - T2) * dS = 0.277 * (523.15 - 298.15) * 750 J/K = 47,175 J

Therefore, the total work produced by the engine is 47,175 J.

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The ratio is very close to 1 C to 2 H. Then the empirical formula is CH₂. Therefore, option B is correct.

An Empirical formula is the chemical formula of a compound that gives the proportions (ratios) of the elements present in the compound but not the actual numbers or arrangement of atoms. This would be the lowest whole number ratio of the elements in the compound.

To find the ratio or the moles of each element by dividing the number of moles of each by the smallest number of moles.

In CH₂ there are one carbon and two hydrogen atoms are present. Hence, CH₂ is an empirical formula.

Thus, option B is correct.

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Answer:

B number of the air molecules.

Explanation:

You should know i am only a 6th grader and i know

Answer:

d

Explanation:

Answer:

Continental Drift

Explanation:

The fossils of sea creatures could have reached the top of Mount Everest due to the continental drift theory suggested by geophysicist, Alfred Wegener. To exaggerate, a piece of evidence that supports Wegener’s hypothesis towards a continental drift is the fact that fossils of sea creatures can’t just end up in any random place like Mount Everest. He suggests that there must be something behind this and gradually it led to his well-known theory. His hypothesis towards a continental drift suggests that his second observation was that fossils of the same prehistoric species were found in different continents that were way apart. There was just no way that all the organisms could cross the oceans and reach all of these places.

Answer:

Method: Measure out 25 cm3 of 0.5 mol dm3 lead(II)nitrate solution and add it to a small beaker. Measure out 25 cm3 of 0.5 mol dm3 of potassium sulfate add it to the beaker and mix together using a stirring rod.

This problem is providing us with the isotopic mass of Ga-71 and its percent abundance, so the isotopic mass of the second isotope is required. At the end, the result turns out to be 68.92547 amu.

In chemistry, isotopes are known as atoms of an element with different atomic masses (isotopic mass) but equal number of protons. In addition, they have a natural occurring abundance as a percentage.

Thus, this problem can be solved by writing the following weighted average for the atomic mass of Gallium:

\(m_{Ga}=m_{Ga-71}*\%ab_{Ga-71}+m_{Ga-?}*\%ab_{Ga-?}\)

Hence, since both percent abundances must sum 100 %, that of the second isotope will be 60.108 %. However, since its mass is unknown, one can use the average atomic mass of Gallium consigned in the periodic table in order to write the following, after plugging in what we have so far:

\(69.723=70. 9247050 amu *0.39892+m_{Ga-?}*0.60108\)

Hence, one can solve for the unknown as follows:

\(m_{Ga-?}=\frac{69.723amu-70. 9247050 amu *0.39892}{0.60108} \\\\m_{Ga-?}=68.92547amu\)

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a) The Lennard-Jones potential predicts the separation r_eq at the minimum energy U_min.

b) The U_min for this interaction at T=298 K is the value obtained from the Lennard-Jones potential equation when r=r_eq.

c) The ratio of U_min to the purely attractive van der Waals component of the interaction potential at r_eq can be calculated by comparing the attractive part (-A/r^6) to the total potential energy U_min.

d) The ratio of r_eq to r_0, where u(r_0)=0.4, can be determined by finding the value of r_eq where the potential energy is equal to 0.4 times the total potential energy at r=r_0.

e) The ratio of r_s to r_0, where r_s is the separation where the magnitude of the attractive adhesion force is maximum, can be determined by finding the value of r where the derivative of the potential energy with respect to r is equal to zero.

f) The value of F_max between the two atoms can be obtained by taking the negative derivative of the potential energy equation with respect to r and evaluating it at r=r_s.

a) The Lennard-Jones potential provides information about the relationship between energy and separation between two interacting atoms.

At the minimum energy (U_min), the potential predicts the separation r_eq, which corresponds to the equilibrium distance between the atoms. This is the distance at which the energy of the system is at its lowest point.

b) To determine the value of U_min at a given temperature (T=298 K), you can substitute the equilibrium separation r_eq into the Lennard-Jones potential equation and calculate the resulting energy value.

This will give you the U_min for the interaction.

c) The Lennard-Jones potential consists of two components: an attractive component (-A/r^6) and a repulsive component (B/r^12).

The ratio of U_min to the purely attractive van der Waals component of the interaction potential at r_eq can be calculated by comparing the magnitude of the attractive component to the total potential energy at the equilibrium separation.

This ratio provides insights into the relative contribution of the attractive force to the overall potential energy at equilibrium.

d) The ratio of r_eq to r_0 can be determined by finding the value of r_eq where the potential energy is equal to 0.4 times the total potential energy at r=r_0.

In other words, you need to solve the Lennard-Jones potential equation for r_eq when the potential energy is equal to 0.4 times the potential energy at r=r_0.

e) The ratio of r_s to r_0 is obtained by finding the value of r where the magnitude of the attractive adhesion force is maximum.

This can be determined by finding the separation r where the derivative of the potential energy equation with respect to r is equal to zero.

The value of r_s represents the separation at which the attractive force between the atoms is strongest.

f) The value of F_max between the two atoms can be obtained by taking the negative derivative of the Lennard-Jones potential energy equation with respect to r and evaluating it at r=r_s.

This will give you the magnitude of the maximum attractive adhesion force between the atoms.

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4Li + O₂ ⇒ 2Li₂O

Li₂O = 2/4 x 3.33 = 1.665

Answer:

Carbon dioxide molecule

Answer:a , d ,e

Explanation:

jusy took quiz

Among the options listed, frost wedging is not directly related to chemical weathering.

Frost wedging is a physical weathering process that occurs in cold climates where water seeps into cracks in rocks, freezes, and expands, exerting pressure on the surrounding rock.

This expansion can cause the rock to break apart over time. While frost wedging does involve the action of water, it does not involve chemical reactions.

On the other hand, the remaining options—hydrolysis, oxidation, and decomposition—are all forms of chemical weathering. Hydrolysis is a chemical reaction where water molecules react with minerals in rocks, leading to their breakdown or alteration.

Oxidation occurs when oxygen reacts with certain minerals, such as iron, in rocks, resulting in their rusting or decomposition. Decomposition, also known as biological weathering, involves the breakdown of rocks through the actions of living organisms, such as lichens and plant roots.

Chemical weathering processes, including hydrolysis, oxidation, and decomposition, can alter the chemical composition and structure of rocks over time.

These processes play significant roles in shaping Earth's surface by breaking down and transforming various rock types.

Frost wedging, although a powerful physical weathering process, is not classified as a chemical process as it does not involve chemical reactions or changes in the mineral composition of rocks.

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Answer:

the answer is B no need to struggle ur answer is correct

Answer:

A is true NaCl

B is false K2Br

C is true

D false its only 0.03 percent

E is true

Answer:

d

Explanation:

both of them are true according to me

Empirical method.It is the compound's most straightforward formula.The simplest whole number ratio of various atoms is contained in this formula. As a result, 12 + 2 * 1 + 16 = 30.Then we figure that 90/30 = 3.The final product is 3*(CH2O) --> C3H6O3.

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Answer:

13.9kJ of energy

Explanation:

This problem must be solved by stages: The heat of the liquid ethanol until boiling point. The change from liquid to gas and the heating of ethanol gas:

Increasing liquid ethanol temperature from 18.1°C - 78.4°C

Q = S*ΔT*m

Where Q is heat, S is specific heat of liquid ethanol: 2.46J/g°C, ΔT is change in temperature: 78.4°C - 18.1°C = 60.3°C, m is mass of ethanol = 13.6g

Q = 2.46J/g°C*60.3°C*13.6g

Q = 2017J

Change from liquid to gas:

The heat of vaporization is defined as the heat required to convert 1 mole of a substance from liquid to gas. The energy required is:

Q = ΔH(vap)*m / MW

Where ΔH is 38.6kJ/mol, m is mass of ethanol = 13.6g, MW is molar weight of ethanol: 46.07g/mol

Q = 11.4kJ

Increasing gas ethanol temperature from 78.4°C - 105.2°C

Q = S*ΔT*m

Where Q is heat, S is specific heat of gas ethanol: 1.43J/g°C, ΔT is change in temperature: 26.8°C, m is mass of ethanol = 13.6g

Q = 1.43J/g°C*26.8°C*13.6g

Q = 521J

Total energy in kJ:

2.0kJ + 11.4kJ + 0.5kJ =

LiAlH₄ (lithium aluminum hydride) and NaBH₄ (sodium borohydride) are commonly used as reducing agents in organic chemistry.

Both compounds serve as powerful sources of hydride ions (H-) that facilitate the reduction of various functional groups.

LiAlH₄ is a strong reducing agent, capable of reducing carbonyl compounds such as aldehydes, ketones, and esters to their corresponding alcohols. Additionally, it can reduce carboxylic acids, amides, and nitriles to primary amines, making it versatile for a range of reactions.

On the other hand, NaBH₄ is a milder reducing agent, selectively reducing aldehydes and ketones to alcohols while leaving other functional groups unaffected. This selectivity allows chemists to perform reductions in the presence of other reactive groups without unwanted side reactions.

In summary, LiAlH₄ and NaBH₄ are valuable tools in organic synthesis for their ability to selectively reduce specific functional groups. LiAlH₄'s strong reducing capabilities enable it to reduce a broad range of groups, whereas NaBH₄'s milder nature allows for selective reductions of aldehydes and ketones.

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Answer:   nuclear fusion, equation:(Z + N) in a nucleus of mass M. The formula is B = (Zmp + Nmn − M)c2, All of the energy from the Sun that reaches the Earth arrives as solar radiation, part of a large collection of energy called the electromagnetic radiation spectrum. Solar radiation includes visible light, ultraviolet light, infrared, radio waves, X-rays, and gamma rays. Radiation is one way to transfer heat.

Explanation: i explained everything in the answer hope this helped

Answer: Function

Explanation: Zinc is found in cells throughout the body.

It is needed for the body's defensive (immune) system to properly work.

It plays a role in cell division, cell growth, wound healing, and the breakdown of carbohydrates.

Answer:

"This conversions relies on the fact that a mole of gas at STP has a volume of 22.4 L. It is important to note, however, that if the conditions of the gas are different this conversion will NOT work. Under those conditions you must use the ideal gas law to convert between moles and liters."

The accident, which was rated level 7 on the International Nuclear and Radiological Event Scale, resulted in high radioactive releases over days 4 to 6. In total, an estimated 940 PBq (I-131 equivalent) of radioactive material entered the ocean.

Following the devastating tsunami in Japan, the Daiichi nuclear disaster occurred on March 11, 2011. As a result of the nuclear plant's damaged reactors, a considerable quantity of radioactive material was discharged into the surrounding environment, including the ocean. The severity of the incident led to its classification as a level 7 event on the International Nuclear and Radiological Event Scale.

Over a period of several days, specifically from days 4 to 6 after the initial disaster, there were substantial releases of radioactive substances. These releases contributed to the significant contamination of the marine ecosystem. It is estimated that a total of approximately 940 petabecquerels (PBq) of radioactive material, measured in terms of iodine-131 equivalence, made its way into the ocean.

The scale of this release and subsequent contamination had far-reaching consequences for the marine environment, raising concerns about the impact on aquatic life and ecosystems, as well as the potential for long-term effects on the overall oceanic ecosystem.

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Answer: todos terminan en tu boca

Explanation:

Hahaha

mary went to the bathroom and found the scale to weight out there so she weighed herself at the bathroom and found her weight was 127lbs

what was scale used for ?

What is the purpose of scales. Scales are weight-measurement devices. Balance scales are widely used to compare object weights or to weigh objects by balancing them against standard weights.

Gravity affects the outcomes of scales. Balances, perplexingly, employ a process known as a force restoration mechanism to generate a force that balances the unknown mass.

A scale factor is defined as the ratio of the scale of a given original item to the scale of a new object that is its representation but of a different size (bigger or smaller).

All of this is made feasible by the mathematical idea of scale factor. The scale factor is a quantity used to grow or decrease the size of forms in two-dimensional and three-dimensional geometry. It may be used to make figures that are similar yet have different proportions.

mary went to the bathroom and found the scale to weight out there so she weighed herself at the bathroom and found her weight was 127lbs

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Answer:

Because electron mass is so insignificant compared to proton and neutron mass that it can be ignored.

Explanation:

Answer:4.81

Explanation:

This is a buffer problem.  You have a buffer because you have a weak acid (CH3COOH) and the salt of that acid (CH3COONa).  We can use the Henderson Hasselbalch equation for a weak acid buffer which is pH = pKa + log [salt]/[acid]

Before plugging in values, let us first calculate the pKa for acetic acid:

pKa = -log Ka = -log 1.8x10-5 = 4.745

Next, we will need to calculate the concentration of the salt, i.e. [CH3COONa]:

1.61 g x 1 mol/82.03 g = 0.01963 moles in 34 ml (0.034 L) = 0.01963 moles/0.034L = 0.5773 M

Finally, we can now plug these values into the HH equation and find the pH:

pH = 4.745 + log [0.5773]/[0.500]

pH = 4.745 + log 1.155

pH = 4.745 + 0.0624

pH = 4.807 = 4.81

CREDIT GOES TO Ph.D. in Biochemistry--University Professor--Chemistry Tutor J.R. S.

Answer

[Ne] 3s² 3p⁶

Explanation:

Neutral sulfur has an atomic number of 16.

Neutral sulfur has 16 electrons and 16 protons.

However, S²⁻ implies neutral sulfur has gain two more electrons.

So, S²⁻ is negatively charged (anion) and has 18 electrons.

Electronic Configuration

Neutal sulfur (S) → 1s² 2s² 2p⁶ 3s² 3p⁴ → [Ne] 3s² 3p⁴.

Charged sulfur (S²⁻) → 1s² 2s² 2p⁶ 3s² 3p⁶ → [Ne] 3s² 3p⁶.

Therefore, the electron configuration of S²⁻ is [Ne] 3s² 3p⁶.

The temperature (in °C) that the ideal gas shifted to is -270.38 °C.

Given data:Initial Temperature, T1 = -15.50 °C = 257.65 K

Initial Pressure, P1 = 4.620 atm

Final Pressure, P2 = 8.710 atm

Initial Volume, V1 = 35.00 L

Final Volume, V2 = 15.00 L

We need to calculate the final temperature, T2.

As the gas is assumed to be an ideal gas, we can use the combined gas equation to solve the problem, that is,

P1V1 / T1 = P2V2 / T2

Let's substitute the values,P1V1 / T1 = P2V2 / T2

(i)At initial conditions, P1V1 / T1 = 4.620 × 35.00 / 257.65 = 0.6294

At final conditions, P2V2 / T2 = 8.710 × 15.00 / T2 = 1.742

Now, let's substitute this value in equation (i)0.6294 = 1.742 / T2T2 = 1.742 / 0.6294= 2.77 K or -270.38 °C

Answer:The temperature (in °C) that the ideal gas shifted to is -270.38 °C.

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