Identify the number of significant figures in the following number: 0.0008

Answer and Explanation:

In an electric field generated between two electrodes there is a separation of charges: a negatively charged electrode called cathode and a positively charged electrode called anode. Ions are charged particles, so they can be positive or negative charges. Opposite charges attract each other. So, the cathode - negatively charged - attracts positively charged particles. On the other hand, the anode - positively charged - attracts negatively charged particles.

Therefore, positive ions move towards the cathode and negative ions move towards the anode.

0.123 mol of methane contains 7.4 x 1022 molecules of methane (ch4). Four hydrogen atoms are joined to the one carbon atom that makes up the molecule methane by single bonds.

It is a gas that is combustible, colourless, odourless, non-toxic, and has a melting point of -161°C. It serves as a fossil fuel, greenhouse gas, and bacterial metabolite, among other things. Avogadro's number refers to the fact that a mole of methane really consists of 6.0221023 molecules. To calculate the required number of molecules, find the substance's molecular weight for one mole. Next, multiply the result by the Avogadro constant after dividing the molar mass value by the molecular mass.

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hope you can read it. hope it's right too :).

All the best.

The tonicity of a solution refers to its ability to cause a change in the shape or size of cells by altering the water content.

In this case, since the membrane is impermeable to glucose but permeable to water, the glucose molecules cannot pass through the membrane, while water molecules can. Since the solution is made of 0.3M glucose, it means that the concentration of glucose in the solution is 0.3 moles per liter.

When blood is added, the impermeable membrane prevents glucose molecules from passing through, but water molecules can move freely. The presence of a higher concentration of glucose inside the membrane than in the blood creates a hypertonic environment. This causes water to move from the blood (where the concentration of solutes is lower) into the solution, via osmosis.

As a result, the solution will become more diluted as water enters it, causing it to expand and potentially change the shape or size of the cells.

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To determine the pH of the solution when 0.2M HCl, 0.4M NaOH, and 0.2M HCN are mixed, we need to consider the acid-base reactions that occur. HCl is a strong acid and NaOH is a strong base, pH of the final solution  comes to be approximately 5.95

So they will completely dissociate in water to form H+ and OH- ions, respectively. The HCN, on the other hand, is a weak acid, and will partially dissociate in water to form H+ and CN- ions. The dissociation reaction of HCN can be represented as follows: HCN + H₂O ⇌ H₃O+ + CN-

The equilibrium constant for this reaction is given by the acid dissociation constant, Ka = [H₃O+][CN-]/[HCN]. At equilibrium, the concentration of HCN will be reduced by some amount, x, and the concentrations of H₃O+ and CN- will increase by x.

Thus, we can write the equilibrium concentrations as follows:

[HCN] = 0.2 - x [H₃O+] = x

CN-] = x

Substituting these values into the expression for Ka, we get:

Ka = (x)(x)/(0.2 - x) = 5 x \(10^{-10}\)

Simplifying this equation, we get:

\(x^2/(0.2 - x) = 5 x 10^{-10}\)

Assuming that x is much smaller than 0.2, we can approximate 0.2 - x as 0.2: \(x^2/0.2 = 5 x 10^{-10}\) Solving for x, we get: x = 1.12 x \(10^{-6}\) M Therefore, the concentration of H₃O+ in the solution is 1.12 x \(10^{-6}\) M. The pH of the solution can be calculated using the formula: pH = -log[H₃O+], Substituting the value of [H₃O+], we get: pH = -log(1.12 x \(10^{6}\)) = 5.95

Therefore, the pH of the solution when 0.2M HCl, 0.4M NaOH, and 0.2M HCN are mixed is approximately 5.95. This value indicates that the solution is slightly acidic, which is expected given the presence of the weak acid, HCN, in the mixture.

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The 95% margin of error for the mean increase in blood pressure that one would expect for cigarette smokers over the time span indicated by the experiment is ±1.98 (rounded off to two decimal places).

The mean increase in blood pressure that one would expect for cigarette smokers over the time span indicated by the experiment can be estimated by using the formula;μ = x ± z(\(a^{2}\)) * σ/√n

Where;μ is the population mean increase.x is the sample mean increase.z(\(a^{2}\)) is the z-scoreα is the level of significanceσ is the population standard deviationn is the sample size.

Substituting the given values into the formula;μ = 9.1 ± 1.96 * 5.5/√37= 9.1 ± 1.98

The mean increase in blood pressure that one would expect for cigarette smokers over the time span indicated by the experiment lies between 7.12 to 11.08.

Hence, the estimated mean increase is between 7.12 to 11.08 millimeters of mercury.

The 95% margin of error can be calculated using the formula;

Margin of error (E) = z(\(a^{2}\)) * σ/√n

Margin of error (E) = 1.96 * 5.5/√37

Margin of error (E) = 1.98 (approximated to two decimal places).

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Answer:

They are positively charged ions.

Explanation:

Though, I am not exactly sure about what do you actually mean by your question, but cations are positively charged ions.

At the equivalence point, the molarities of the two solutions are equal, so the volume of the NaOH required to neutralize the HCl is also 40.0 mL, for the titration.

The concentration of HCl multiplied by the volume of HCl must be equal to the concentration of NaOH multiplied by the volume of NaOH. The concentration of the HCl is 0.120 moles/L and the volume of the sample is 40.0 mL. This means that the concentration of NaOH multiplied by the volume of NaOH must equal 0.120 x 40.0 = 4.8 moles. The concentration of NaOH is also 0.120 moles/L, so the volume of NaOH must be 4.8/0.120 = 40.0 mL. This means that 40.0 mL of 0.120 m NaOH is needed at the equivalence point of the titration to neutralize a 40.0 mL sample of 0.120 m HCl.  To determine the volume of 0.120 m NaOH needed at the equivalence point of a titration, the moles of HCl and NaOH must be equal. This means that the concentration of HCl multiplied by the volume of HCl must be equal to the concentration of NaOH multiplied

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Answer:

C

Explanation:

Just took the test

Explanation:

I hope it helps

ya welcome

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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Answer:Arsenic trifluoride

Arsenic trifluoride | AsF3 - PubChem.

Explanation:

To determine the pH of a solution using a pH indicator paper, you need a color chart or a color scale that corresponds to different pH values.

This color chart or scale is used to compare the color of the pH indicator paper after it has been immersed in the solution. The pH indicator paper is impregnated with a universal pH indicator, which is a chemical compound that changes color depending on the acidity or alkalinity of the solution.

The indicator undergoes a chemical reaction with the hydrogen ions (H+) or hydroxide ions (OH-) present in the solution, resulting in a color change.

By comparing the color of the pH indicator paper with the color chart or scale, you can determine the approximate pH of the solution. The color chart usually provides a range of colors corresponding to different pH values, allowing you to match the observed color to the nearest pH value.

In the hypothesis mentioned, the aim is to calibrate a cabbage pH indicator using the pH values obtained from a universal pH indicator. Therefore, in addition to the pH indicator paper and color chart, you would also need a range of solutions with known pH values to establish a calibration curve specific to the cabbage pH indicator.

In summary, to determine the pH of a solution using a pH indicator paper, you need a color chart or scale that correlates the observed color of the pH indicator paper with different pH values. This chart or scale serves as a reference for interpreting the color change and determining the pH of the solution.

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Answer: COLOR KEY

Explanation: CS

Answer:

A

Explanation:

Determine the mass number for each of the isotopes, which is obtained by adding the number of protons and the number of neutrons. Hence, isotope A has a mass number of 1, isotope B has a mass number of 2, and isotope C has a mass number of 3. To determine the average atomic mass, we multiply the atomic mass of each isotope by its abundance. Hence, we obtain (0.99985 × 1 amu) + (0.00015 × 2 amu) + (0.00 × 3 amu) = 1.00 amu

Species which has the largest dipole moment is CH3Cl.

Dipole moment can be defined as the product of the distance between the centers of positive and negative charge and the magnitude of the charge. It is denoted by μ.

The trend of dipole moment in case of yhe halogens areas below:

The dipole moment of species CH3Cl is greater than CH3F due to the electron affinity.

Thus, we concluded that species which has the largest dipole moment is CH3Cl.

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Answer: 255 pm

Explanation: Hope this helps!

Answer:

Im going to say sleep

Explanation:

The fugacity in atm for pure ethane at 310 K and 20.4 atm is given by the equation: f = 20.4 exp (-Δg1/RT). The change in chemical potential between this state and a second state of ethane where the temperature is constant but the pressure is 24 atm is -0.0911RT.

Fugacity is a measure of the escaping tendency of a component in a mixture, which is defined as the pressure that the component would have if it obeyed ideal gas laws. It is used as a correction factor in the calculation of equilibrium constants and thermodynamic properties such as chemical potential. Here we need to determine the fugacity in atm for pure ethane at 310 K and 20.4 atm and the change in the chemical potential between this state and a second state of ethane where the temperature is constant but the pressure is 24 atm. So, using the formula of fugacity: f = P.exp(Δu/RT) Where P is the pressure of the system, R is the gas constant, T is the temperature of the system, Δu is the change in chemical potential of the system.  Δu = RT ln (f / P)The chemical potential at the initial state can be calculated using the ideal gas equation as: PV = nRT    

=>  P

= nRT/V

=> 20.4 atm

= nRT/V

=> n/V

= 20.4/RT The chemical potential of the system at the initial state is:

Δu1 = RT ln (f/P)

= RT ln (f/20.4) Also, we know that for a pure substance,

Δu = Δg. So,

Δg1 = Δu1 The change in pressure is 24 atm – 20.4 atm

= 3.6 atm At the second state, the pressure is 24 atm.

Using the ideal gas equation, n/V = 24/RT The chemical potential of the system at the second state is: Δu2 = RT ln (f/24) = RT ln (f/24) The change in chemical potential is Δu2 – Δu1 The change in chemical potential is

Δu2 – Δu1 = RT ln (f/24) – RT ln (f/20.4)

= RT ln [(f/24)/(f/20.4)]

= RT ln (20.4/24)

= - 0.0911 RT Therefore, the fugacity in atm for pure ethane at 310 K and 20.4 atm is:

f = P.exp(Δu/RT)

=> f

= 20.4 exp (-Δu1/RT)

=> f

= 20.4 exp (-Δg1/RT) And, the change in the chemical potential between this state and a second state of ethane where the temperature is constant but pressure is 24 atm is -0.0911RT. Therefore, the fugacity in atm for pure ethane at 310 K and 20.4 atm is given by the equation: f = 20.4 exp (-Δg1/RT). The change in chemical potential between this state and a second state of ethane where the temperature is constant but the pressure is 24 atm is -0.0911RT.

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Answer:

Explanation: Sodium has an atomic number of 11, so it has 11 protons. The atomic mass is 23, so there are 23 − 11 = 12 neutrons. The charge is +1, so there is 1 more proton than electrons, so there are 10 electrons

Explanation:

If a bullet train travelled a distance of 246 miles in 2 hours, then the average speed of train is 122.45 miles/h.

The amount of ground an object covers in a given amount of time is known as its speed in physics. Alternatively put, speed refers to the rate of movement of an object. The length of the unit time can be in seconds, hours, days, or years. It informs us of an object's motion's speed or slowness. Quantity is a scalar, and speed is it. The SI unit of speed is the m/s.

The majority of things and bodies don't move at a constant speed, like the MRT train, which begins at a station at rest, accelerates until it reaches constant speed (also called cruising speed), then slows down to a stop at the next station. Thus, defining average speed <v> as opposed to actual speed v is more beneficial.

We know that average speed = sum of  distance/ sum of time

Here given that distance is 245 miles and time is 2 hours

So, Speed is

s = d/t

  =  245/2

  = 122.5 miles/h

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Answer:life

Explanation:

because we act like we have no cells

Based on the data provided,  the rate of the given reactions are:

a. reaction rate =  0.0132 M/sec

b. rate of change of [H⁺] = 8.8 * 10⁻³ M/sec

Reaction rate = change in concentration of reactant or product/ time taken

Change in concentration of I⁻ = 1.000 M - 0.868 M= 0.132

time taken = 10 s

reaction rate = 0.132/10

Rate of reaction = 0.0132 M/sec

From the equation of the reaction 3 moles of I⁻ are used up for every 2 moles of H⁺

Hence, the rate of change of [H⁺] = 0.0132 M/sec * 2/3

rate of change of [H⁺] = 8.8 * 10⁻³ M/sec

Therefore, the rate of the given reactions are:

a. reaction rate =  0.0132 M/sec

b. rate of change of [H⁺] = 8.8 * 10⁻³ M/sec

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This equation shows the reaction of cis-2,3-diethyloxirane with hydrogen chloride to form 4-chloro-3-hexanol. There are in total of 2 stereoisomers are possible for 4-chloro-3-hexanol.

The equation you provided shows the reaction of cis-2,3-diethyloxirane with hydrogen chloride to form 4-chloro-3-hexanol. In this reaction, the cis-2,3-diethyloxirane molecule is a chiral molecule, which means that it has two non-superimposable mirror images, or stereoisomers. The hydrogen chloride molecule is achiral, meaning it does not have stereoisomers. When a chiral molecule reacts with an achiral molecule, the resulting product will generally be achiral. However, in some cases, the reaction can produce a chiral product if the reacting chiral molecule is present in both of its stereoisomers. In this case, it is possible that the cis-2,3-diethyloxirane molecule could react with hydrogen chloride in both of its stereoisomers, resulting in two different stereoisomers of 4-chloro-3-hexanol.

Therefore, the total number of stereoisomers possible for 4-chloro-3-hexanol is 2.

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The correct order of increasing bond angles among the given molecules is SiO₂ < NO₂ < ClO₂

SiO₂ (silicon dioxide) has a linear molecular geometry with a bond angle of 180 degrees. It consists of two oxygen atoms bonded to a central silicon atom.

NO₂ (nitrogen dioxide) has a bent molecular geometry with a bond angle of approximately 134 degrees. It consists of a nitrogen atom double-bonded to an oxygen atom and a single-bonded oxygen atom.

ClO₂ (chlorine dioxide) has a bent molecular geometry with a bond angle of approximately 117 degrees. It consists of a chlorine atom double-bonded to one oxygen atom and single-bonded to another oxygen atom.

Therefore, the correct order is SiO₂< NO₂< ClO₂.

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Answer:

The Correct option is "+1"

Answer:What is used up in and stops a chemical reaction? (a) percent yield (b) limiting reactant (c) theoretical yield (d) excess reactant

The correct option is (b)

Explanation:

A chemical reaction is a chemical combination,rearrangement or disintegration of chemical substance(s) (called reactants) to form new chemical substance(s) (called products).

A limiting reactant is the reactant that is totally used up during the course of a reaction. When this reactant is used up, it limits the amount of products formed and eventually stops the chemical reaction.

Explanation:

The limiting reagent is the reactant that is used up completely. This stops the reaction and no further products are made. ... This method is most useful when there are only two reactants. The limiting reagent can also be derived by comparing the amount of products that can be formed from each reactant.

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Explanation:

While CO2 can be distilled from the air, that method is expensive and inefficient. Therefore, it is usually captured from other sources where it is a waste material. This could be anything from brewing beer to burning fossil fuels. However, the most efficient way of producing carbon dioxide is from ammonia.