use a periodic table to write the electron configuration of selenium

a) Equating this to 4.1, we get: 0.1376 / (molar mass of unknown liquid) = 4.1, or molar mass of unknown liquid = 0.1376 / 4.1 = 0.0336 g/mol.

b) The molarity is: (13.34 / (molar mass of unknown liquid)) × 1 = 13.34 / (molar mass of unknown liquid) M.

c) The mass of unknown liquid is: (84.2 g) - (74.3 g) = 9.9 g.

d) The mass of water in the decanted solution is 74.3 g (as calculated in part c).

e) The amount of unknown liquid in 1 kg of water is: (1 kg) × (0.0098) × (1360 g/mol) = 13.33 g.

f) The student calculated the molar mass of the unknown liquid to be 0.0336 g/mol.

a. The freezing point depression can be calculated using the formula: ΔTf = Kf × m, where ΔTf is the change in freezing point, Kf is the freezing point depression constant (1.86 °C/m for water), and m is the molality of the solution. The change in freezing point is (0.4 - (-3.7)) = 4.1 °C. The molality can be calculated using the formula: m = (moles of solute) / (mass of solvent in kg). Since the mass of solvent (water) is (84.2 - 9.9) = 74.3 g = 0.0743 kg, and assuming that the solute (unknown liquid) does not dissociate, we can use the formula: moles of solute = (mass of solute) / (molar mass of solute). Therefore, m = (9.9 g) / [(molar mass of unknown liquid) × 0.001 kg/g] = 9.9 / (molar mass of unknown liquid) mol/kg. Substituting the values, we get: ΔTf = (1.86 °C/m) × (9.9 / (molar mass of unknown liquid)) × 0.0743 kg = 0.1376 / (molar mass of unknown liquid) °C. Equating this to 4.1, we get: 0.1376 / (molar mass of unknown liquid) = 4.1, or molar mass of unknown liquid = 0.1376 / 4.1 = 0.0336 g/mol.

b. The molarity of the unknown liquid can be calculated using the formula: molality = (moles of solute) / (mass of solvent in kg). Since we have already calculated the moles of solute as (9.9 g) / (molar mass of unknown liquid), we need to convert the mass of solvent to kg, which is 0.0743 kg. Therefore, the molality is: (9.9 g) / [(molar mass of unknown liquid) × 0.0743 kg] = 13.34 / (molar mass of unknown liquid) mol/kg. Since molarity is defined as moles of solute per liter of solution, we need to convert the molality to molarity by multiplying it with the density of water, which is approximately 1 kg/L at room temperature. Therefore, the molarity is: (13.34 / (molar mass of unknown liquid)) × 1 = 13.34 / (molar mass of unknown liquid) M.

c. The mass of unknown liquid in the decanted solution can be calculated by subtracting the mass of water from the mass of the solution. The mass of water is (0.0743 kg) × (1000 g/kg) = 74.3 g. Therefore, the mass of unknown liquid is: (84.2 g) - (74.3 g) = 9.9 g.

d. The mass of water in the decanted solution is 74.3 g (as calculated in part c).

e. If we assume that the concentration of the unknown liquid in the solution is the same as in the experiment, then we can use the formula: moles of solute = (molarity) × (volume of solution in L). Since we want to find the volume of the unknown liquid in 1 kg of water, we can assume that the total volume of the solution is 1 L. Therefore, the moles of solute is: (13.34 / (molar mass of unknown liquid)) × 1 = 13.34 / (molar mass of unknown liquid) mol. Since the mass of 1 kg of water is 1000 g, and assuming that the density of the solution is the same as that of water, the mass of the solution is 1000 g + 9.9 g = 1009.9 g. Therefore, the concentration of the unknown liquid in the solution is: (9.9 g) / (1009.9 g) = 0.0098. Substituting the values, we get: 13.34 / (molar mass of unknown liquid) = 0.0098, or molar mass of unknown liquid = 1360 g/mol. Therefore, the amount of unknown liquid in 1 kg of water is: (1 kg) × (0.0098) × (1360 g/mol) = 13.33 g.

f. Based on the data, the student calculated the molar mass of the unknown liquid to be 0.0336 g/mol (as calculated in part a).

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The de Broglie wavelength of a hydrogen atom traveling at 485 m/s is approximately 3.31 picometers.

To calculate the de Broglie wavelength, we can use the formula λ = h/mv, where λ is the de Broglie wavelength, h is Planck's constant, m is the mass of the particle, and v is its velocity.

For a hydrogen atom, the mass is approximately 1.67 × \(10^-27 kg\). Converting the velocity of 485 m/s to SI units, we get 4.85 × \(10^2 m/s.\) Substituting these values in the formula, we get λ = (6.626 × \(10^-34 J.s\))/(1.67 × \(10^-27 kg\) × 4.85 × \(10^2 m/s\)) = 3.31 pm.

This wavelength is much smaller than the size of an atom, indicating that hydrogen behaves as a particle rather than a wave at this velocity.

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According to common weather maps of the region surrounding Salem, Massachusets, the weather typically associated with the air pressure system is rain.

Air pressure systems define areas where the interaction between temperatures and air currents creates weather. Air pressure systems can be of two types:

Given the nature of warm air and its tendency to rise, warmer regions tend to fall under the low-pressure system category. These systems, due to the movement of the warm air, have lower pressure at their center than in the areas surrounding them.

As the wind blows towards the low-pressure air systems, the cooler and warmer air meet within the atmosphere, which causes the water vapor to condense and form clouds. Oftentimes, these clouds then precipitate, causing rain.

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The two most important attitudes that managers will approach their jobs with are: . Organizational commitment and Job satisfaction.

Organizational commitment: Organizational commitment refers to the level of attachment, loyalty, and dedication that managers have towards their organization. Managers who are highly committed to their organization are more likely to invest their time, energy, and effort into achieving the organization's goals and objectives. They exhibit a sense of responsibility and are willing to go above and beyond their formal job requirements. Organizational commitment contributes to higher job performance and lower turnover rates.

Job satisfaction: Job satisfaction refers to the extent to which managers are content and fulfilled in their roles. Managers who experience high job satisfaction are more likely to be motivated, engaged, and productive. They derive a sense of accomplishment and fulfillment from their work, leading to increased job performance and job-related well-being. Job satisfaction is influenced by various factors such as work-life balance, supportive work environment, opportunities for growth and development, and recognition for their contributions.

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Answer:

Heat

Explanation:

Heat will always flow from the warmer object to the colder object. The heat transfer will stop when the two objects are at the same temperature and reach thermal equilibrium.

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Answer:

when both object are the same temperature

Explanation:

Answer:

There is at least 2 ways. First, the isotopes are allowed to heat water into steam, and the steam turns a generator. 2nd, the isotopes are allowed to heat one end of a "thermopile", and the thermopile powers electronics

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The amount of energy needed to raise the temperature of 10 g of gold from 30°C to 40°C is 12.9 joules.

To calculate the amount of energy needed to raise the temperature of a substance, we can use the following formula;

Q = m × c × \(Δ_{T}\)

Where Q is the amount of energy (in joules), m is the mass of the substance (in grams), c is the specific heat capacity of the substance (in joules per gram per degree Celsius), and \(Δ_{T}\) is change in temperature (in degrees Celsius).

The specific heat capacity of gold is 0.129 joules per gram per degree Celsius.

Using this information, we can calculate the amount of energy needed to raise the temperature of 10 g of gold from 30°C to 40°C;

Q = 10 g × 0.129 J/g°C × (40°C - 30°C)

Q = 10 g × 0.129 J/g°C × 10°C

Q = 12.9 J

Therefore, the amount of energy needed is 12.9 joules.

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Answer:

The difference between a hot cup of water and a cold one in terms of thermal energy can be described as the amount of heat energy that is present in each cup. The hot cup of water contains more thermal energy than the cold one due to its higher temperature. This means that the hot cup has more energy to transfer to its surroundings, and will cool down faster than the cold cup. The thermal energy in a cup of water is related to the temperature, with hotter water having a higher thermal energy than colder water.

Explanation:

Solvent extraction, or liquid-liquid extraction, is a commonly employed technique for separating specific compounds from a mixture.

When conducting experiments involving solvent extraction, it is crucial to include the density of the solvent as a physical property in the pre-lab write-up of your lab notebook.

Solvent extraction, or liquid-liquid extraction, is a commonly employed technique for separating specific compounds from a mixture.

This method involves shaking the mixture containing two immiscible liquids, allowing them to separate into distinct layers, and subsequently isolating the desired compound.

The density of the solvents plays a vital role in solvent extraction experiments. It determines the layer identification after phase separation.

By understanding the relative densities of the two liquids involved, we can predict which liquid will be the top layer and which will be the bottom layer.

The less dense liquid will float on top, while the more dense liquid will sink to the bottom.

This knowledge enables us to determine the layer that contains the target compound of interest.

Including the density of the solvents in the pre-lab write-up ensures accurate layer identification during the solvent extraction process.

It is an essential physical property that aids in the successful isolation of desired compounds.

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The name of the organic compound is 2-methyl pentane. The given organic compound is a five-carbon system with a substitution at the C-2 carbon. The naming of an organic compound is done according to the rules given by IUPAC.

The given organic compound has 5 carbon in its main chain. So It has the root word Pent. Since, all the bonds are single bonds, the organic compound is saturated, hence it has the suffix -ane. Hence the unsubstituted straight chain is pentane.

Numbering is done from right to left, because when the numbering is from right to left, the substituted carbon gets C-2, when it is numbered from left to right, the substituted carbon gets C-4. So the numbering is from the right and the substituted carbon is C-2. The substituent is a single carbon system, a methyl substituent. So the organic compound is named 2-methyl pentane .

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The process of two complementary single-stranded DNA and/or RNA molecules joining together to generate a double-stranded molecule is known as hybridization in the context of genomics. The proper base pairing between the two single-stranded molecules is necessary for the bonding.Sp3 hybridization is the process of hybridization in which the 1s and 3p orbitals of the same element are mixed and recast to create new hybrid orbitals with the same energy, symmetry, and fixed orientation in space. An example is the creation of the methane molecule.

Linear, trigonal planar, tetrahedral, trigonal bipyramidal, and octahedral are the five fundamental hybridization shapes.

To find the formal charge of a Lewis structure, count the number of electrons "owned" by each atom. Count all lone pairs and half of the bond electrons. The difference between the number of valence electrons in an atom and the number it has is the formal charge. Fluorine (and all halogens) tend to form bonds and have three unshared pairs of electrons. None of these atoms have a formal charge in their electronic configuration.

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a single neutral atom of zinc has 30 protons

The 3d orbital experiences the most shielding from both the 3s and 3p orbitals, leading to the highest energy among the three orbitals.

In multielectron atoms, electron shielding refers to the repulsion between electrons in different energy levels.

This repulsion leads to energy differences among the 3s, 3p, and 3d orbitals. The 3s orbital experiences the least shielding because it is closer to the nucleus and shielded by fewer electrons.

Consequently, it has the lowest energy. The 3p orbital is shielded by both the 3s and 3d orbitals, resulting in higher energy.

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In a charcoal-water-unknown mixture, this must be boiled in opposition because the coal is insoluble, and with the heated mixture the coal can be removed.

It is used in the chemical sciences as a technique used to purify chemicals by heating materials to temperatures above the crystallization of each compound.

Therefore, when a component is heated, the impurities are dissolved and can be removed from the solution, generating the purification of the compound.

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Answer:

It is position 3

Explanation:

Because the further the magnets are the higher the potential energy, and in position 3 the globe is the furthest from the base meaning that in base 3 the magnetic potential energy is the highest or greatest there.

Answer:

\(\boxed{\tt d=5g/cm^3}\)

Explanation:

The density of a substance can be found using the following formula.

\(d=\frac{m}{v}\)

where \(m\) is the mass and \(v\) is the volume.

The mass of this substance is 90 grams and the volume is 18 cubic centimeters.

\(m= 90 g \\v= 18 cm^3\)

Substitute the values into the formula.

\(d=\frac{90 g}{18 cm^3}\)

Divide 90 grams by 18 cubic centimeters.

\(d=5 g/cm^3\)

The density of the substance is 5 grams per cubic centimeter.

Answer:

a) 1.567 x 10^9

b) 2.36 x 10^(-5)

Answer:

For all these questions, we want to find the empirical and molecular formulae of various compounds given their percent composition and molar mass. The technique used to answer one of the questions can accordingly be applied to all of them.

Approaching the first question, we treat the percentages of each element as the mass of that element in a 100 g compound (as the percentages add up to 100%). So, our 100 g compound comprises 7.74 g H and 92.26 g C.

Next, we convert these mass quantities into moles. Divide the mass of each element by its molar mass:

7.74 g H/1.00794 g/mol = 7.679 mol H

92.26 g C/12.0107 g/mol = 7.681 mol C.

Then, we look for the molar quantity that's the smallest ("smaller," in this case, since there are only two), and we divide all the molar quantities by the smallest one. Here, it's a very close call, but the number of moles of H is slightly smaller than that of C. So, we divide each molar quantity by the number of moles of H:

7.679 mol H/7.679 mol H = 1

7.681 mol C/7.679 mol H ≈ 1 C/H (the value is actually slightly larger than 1, but we can treat it as 1 for our purposes).

The quotients we calculated represent the subscripts of our compound's empirical formula, which should provide the most simplified whole number ratio of the elements. So the empirical formula of our compound is C₁H₁, or just CH.

Here, it just so happens that we obtained whole number quotients. If we end up with a quotient that isn't a whole number (e.g., 1.5), we would multiply all the quotients by a common number that would give us the most simplified whole number ratio (so, if we had gotten 1 and 1.5, we'd multiply both by 2, and the empirical formula would have subscripts 2 and 3).

To find the molecular formula (the actual formula of our compound), we use the molar mass of the compound, 78.1134 g/mol. The molar mass of our "empirical compound," CH, is 13.0186 g/mol. Since our empirical formula represents the most simplified molar ratio of the elements, the molar masses of our "empirical compound" and the actual compound should be multiples of one another. We divide 78.1134 g/mol by 13.0176 g/mol and obtain 6. The subscripts in our molecular formula are equal to the subscripts in our empirical formula multiplied by 6.

Thus, our molecular formula is C₆H₆.

---

As mentioned before, all the questions here can be answered following the procedure used to answer the first question above. In any case, I've provided the empirical and molecular formulae for the remaining questions below for your reference.

2. Empirical formula: C₁₃H₁₂O; molecular formula: C₁₃H₁₂O

3. Empirical formula: CH; molecular formula: C₈H₈

4. Empirical formula: C₂HCl; molecular formula: C₆H₃Cl₃

5. Empirical formula: Cl₄K₂Pt; molecular formula: Cl₄K₂Pt

6. Empirical formula: C₂H₄Cl; molecular formula: C₄H₈Cl₂

Protons and electrons in an atom carry opposite charges and are attracted to each other, which maintains the boundaries of the atom as an electrically neutral system.

Atoms consist of a positively charged nucleus containing protons and neutrons, surrounded by negatively charged electrons in different energy levels or orbitals.

Protons carry a positive charge, while electrons carry a negative charge. Due to the opposite charges, protons and electrons are attracted to each other through the electromagnetic force.

This attraction between protons and electrons helps to maintain the stability and boundaries of the atom. The positive charge of the protons in the nucleus creates an electric field that attracts the negatively charged electrons towards it.

At the same time, the electrons' motion creates an opposing electric field, resulting in a balance between the attractive and repulsive forces within the atom.

As a result of this balance, the atom remains electrically neutral overall, meaning it has an equal number of protons and electrons. The attractive force between protons and electrons prevents the electrons from escaping the atom and maintains the integrity of the atom's structure.

In summary, the attraction between protons and electrons in an atom plays a vital role in keeping the atom electrically neutral and maintaining the boundaries of the atom as an interconnected system.

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: PM2.5 is defined as the mass concentration of particles in the air less than or equal to 2.5 micrometers in diameter.Question 15: False, carbon dioxide (CO2) is not considered a criteria air pollutant.

Question 16: The closest answer is 50%, but the exact percentage is not provided in the question.Question 17: The term "photochemical smog" is most synonymous with ozone (O3), which is a criteria air pollutant.Question 18: True, attainment of ambient air quality standards requires that measured concentrations at all monitoring stations within an air district are below ambient air standards.

Question 14 asks about the definition of PM2.5. PM2.5 refers to particulate matter with a diameter less than or equal to 2.5 micrometers. It represents the mass concentration of particles suspended in the air, which are small enough to be inhaled into the respiratory system and can have adverse health effects.

Question 15 states whether carbon dioxide (CO2) is a criteria air pollutant. Criteria air pollutants are a set of pollutants regulated by environmental agencies due to their detrimental impact on air quality and human health. However, carbon dioxide is not considered a criteria air pollutant because it does not directly cause harm to human health or the environment in the same way as pollutants like ozone or particulate matter.

Question 16 asks about the percentage of carbon monoxide (CO) emissions from mobile sources in Santa Clara County. While the exact percentage is not provided in the question, the closest answer option is 50%. However, it is important to note that the precise percentage may vary depending on specific local conditions and emissions sources.

Question 17 inquires about the criteria air pollutant most synonymous with the term "photochemical smog." Photochemical smog is primarily associated with high levels of ground-level ozone (O3). Ozone is formed when nitrogen oxides (NOx) and volatile organic compounds (VOCs) react in the presence of sunlight, creating a hazy and polluted atmospheric condition.

Question 18 addresses the concept of "attainment" of ambient air quality standards. To achieve attainment, measured concentrations of pollutants at all monitoring stations within an air district must be below the established ambient air quality standards. This ensures that the air quality in the given area meets the required standards for protecting human health and the environment.

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Answer:

a pH above 7 is alkali

a pH lower than 7 is acidic

Answer:

The average atomic mass of zinc is 65.38 u.

Explanation:

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That 1500 kJ of energy were transferred to water at 20.0°C. Heat capacity (c) for liquid water is 4.18 J/g C​. mass of water could be brought to the boiling point is 4485 g.

given that :

heat energy = 1500 kJ

heat capacity , c = 4.18 J/g °C

initial temperature = 20.0°C

boiling of water ,final temperature = 100 °C

Q = mcΔT

m = Q / (cΔT)

m = 1500 / ( 4.18 × ( 100 °C - 20 °C )

m = 1500 / 334.4

m = 4.485 kg = 4485 g

Thus, That 1500 kJ of energy were transferred to water at 20.0°C. Heat capacity (c) for liquid water is 4.18 J/g C. ​mass of water could be brought to the boiling point is 4485 g.

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Answer:

A

Explanation:

I learned this last year

Answer:

Intensity

Explanation:

The correct answer is -Intensity

Reason -

Intensity has no affect on whether or not the photoelectric effect occurs.

As frequency , wavelength are inversely proportional.

Answer: C)

Explanation:

Answer:

1st one: carbon dioxide

2nd: Glucose

3rd: Oxygen

4th: Energy

Sorry if this is wrong because I don't see the options!

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The growth rate of the country's population if it was doubling it's population every 13 years is 5. 38%.

To calculate the growth rate of a population that is doubling every 13 years, we can use the rule of 70, which states that the approximate number of years it takes for a population to double can be calculated by dividing 70 by the annual growth rate.

So if a population is doubling every 13 years, we can find the annual growth rate as follows:

70 / 13 = 5.38

Therefore, the annual growth rate of this population would be approximately 5.38%.

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The broadening of spectral lines can be caused by various factors, including: Doppler Broadening, Natural Broadening,  Pressure Broadening,  Stark Broadening, Zeeman Broadening, Instrumental Broadening .

1. Doppler Broadening: This occurs when there is motion between the source of light and the observer. If the emitting or absorbing particles are moving toward or away from the observer, the observed wavelength of the light will be shifted due to the Doppler effect. This results in a broadening of the spectral lines.

2. Natural Broadening (or Homogeneous Broadening): This is a broadening of spectral lines caused by the inherent properties of the emitting or absorbing particles. Quantum mechanical uncertainties in energy levels and transition probabilities lead to natural broadening. It results in a symmetric broadening of the lines with a characteristic shape known as a Lorentzian profile.

3. Pressure Broadening (or Collisional Broadening): This occurs when the emitting or absorbing particles experience frequent collisions with other particles in a dense environment. The collisions cause a perturbation in the energy levels and transition probabilities, resulting in a broadening of the spectral lines. Pressure broadening typically leads to a symmetric Gaussian profile.

4. Stark Broadening: Stark broadening occurs in the presence of an external electric field. The electric field causes a splitting of energy levels and leads to a broadening of spectral lines.

5. Zeeman Broadening: Zeeman broadening occurs in the presence of an external magnetic field. The magnetic field causes a splitting of energy levels, resulting in a broadening of spectral lines. Zeeman broadening is particularly noticeable when the magnetic field is strong.

6. Instrumental Broadening: This type of broadening is caused by limitations or imperfections in the measuring instrument used to observe the spectral lines. Factors such as the resolving power of the instrument, detector response, and instrumental noise can contribute to the broadening of the observed lines.

It's important to note that different broadening mechanisms can operate simultaneously or dominantly depending on the specific conditions. The combined effect of these broadening mechanisms determines the overall shape and width of the spectral lines observed in experiments and astronomical observations.

In summary, the broadening of spectral lines can be caused by factors such as Doppler effect, natural broadening, pressure broadening, Stark broadening, Zeeman broadening, and instrumental broadening. These mechanisms introduce variations in the energy levels and transition probabilities of the emitting or absorbing particles, resulting in a broadening of the observed spectral lines.

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The number of hamburgers sold on Wednesday is 275.

Let's assume the number of hamburgers sold is x.

According to the given information, the number of cheeseburgers sold is 70 more than the number of hamburgers. So, the number of cheeseburgers sold can be expressed as x + 70.

The total number of hamburgers and cheeseburgers sold is given as 620, so we can set up the following equation:

x + (x + 70) = 620

Combining like terms, we get:

2x + 70 = 620

Subtracting 70 from both sides of the equation:

2x = 550

Dividing both sides by 2:

x = 275

Therefore, the number of hamburgers sold on Wednesday is 275.

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