which of the following is a true statement? which of the following is a true statement? evaporation of water is an endothermic process where δh is negative. a combustion reaction is an exothermic process where δh is negative. freezing of water is an exothermic process where δh is positive. melting of ice is an endothermic process where δh is negative.

Answer:

Multiply n by M to convert to the mass, m:

m = n × M = (0.09299 mol)/1 × (60.083 g)/(1 mol) = 5.5871 g

Explanation:

Convert from molecules into grams:

5.6×10^22 molecules silicon dioxide (SiO2)

Determine the number of molecules, N_molecules:

N_molecules = 5.6×10^22 molecules

Look up Avogadro's constant, N_A, to find the number of molecules in a mole:

N_A = 6.022×10^23 molecules/mol

Divide N_molecules by N_A to convert to the amount of substance, n:

n = N_molecules/N_A = N_molecules/1 × 1/N_A = (5.6×10^22 molecules)/1 × (1 mol)/(6.022×10^23 molecules) = 0.09299 mol

Calculate the molar mass, M, of SiO_2:

M = 60.083 g/mol

Answer:

15000N/m²

Explanation:

Given parameters:

Force exerted by the girl  = 450N

Area  = 300cm²

Unknown:

Pressure exerted by her feet  =?

Solution:

Pressure is the force per unit area on a body;

    Pressure  = \(\frac{force }{area}\)

We need to convert the given area to m²;

        10000cm²   =  1m²

        300cm²  = \(\frac{300}{10000}\)   = 0.03m²

Pressure = \(\frac{450}{0.03}\)   = 15000N/m²

Answer:

Definetly Nitrogen

Explanation:

Nitrogen is the most electronegative

Which statement about exothermic reactions is TRUE?

A.In an exothermic reaction, energy is absorbed, bonds are broken, and the temperature decreases.

In this case, the partial pressures of nitrogen (N2), oxygen (O2), and helium (He) are given as 219 torr, 106 torr, and 244 torr, respectively. The total pressure of the gas mixture is 569 torr.

The total pressure of a gas mixture is the sum of the partial pressures of its individual components. In this case, the partial pressures of nitrogen (N2), oxygen (O2), and helium (He) are given as 219 torr, 106 torr, and 244 torr, respectively.

To find the total pressure, we simply add these partial pressures together:

Total pressure = Partial pressure of N2 + Partial pressure of O2 + Partial pressure of He

            = 219 torr + 106 torr + 244 torr

            = 569 torr

Therefore, the total pressure of the gas mixture is 569 torr.

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In order to reduce the risk of radiation exposure to individuals and environmental contamination, radioactive wastes are kept. The wastes' radioactivity decreases over time.

Large steel and concrete barrels that contain the garbage are typically properly sealed, although accidents and leaks can still happen. Cancerous growths can result from the severe negative impacts of nuclear waste on life.

Currently, dry casks are used to store all of the nuclear waste that a power plant produces over the course of its lifetime. Since 1987, Yucca Mountain in Nevada has been intended as a permanent disposal location for spent nuclear material.

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Answer:

48

Explanation:

because you add 6 and 6 and 12 to get it

Answer:

you will have to use T = 1/10

The east to west daily motions of stars, planets, the Moon, and the Sun are caused by the rotation of the Earth on its axis. The Earth and all the planets revolve around the Sun on circular orbits. This produces the change in constellations observed from one time of year to the next.

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The number of moles added to increase the volume of the gas from 8.51 L to 15.5 L is 8.67 moles.

The initial volume of the gas is 8.15 L and final volume of gas is 15.5 L and the initial moles are 9.51 moles.

As per the Ideal gas equation,

PV = nRT

where,

P is pressure,

V is volume of gas,

n is the number of moles of gas,

R is the gas constant,

T is the temperature of the gas.

Rearranging the equation,

V/n = RT/P

The left side is constant, so, it is valid to see,

V₁/n₁ = V₂/n₂

V₁ is initial volume,

n₁ is the initial moles,

V₂ is the final volume,

n₂ is the final moles.

So, we can write this by putting the values,

8.51/(9.5) = 15.5/n₂

n₂ = 18.17

The number of moles added = n₁ - n₂

Added moles = 8.67 moles

The moles added are 8.67 moles.

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Evaporation is the process by which a liquid converts into a gas or vapor at a temperature below its boiling point. Latent heat of fusion is the amount of heat required to convert a solid into a liquid without any change in temperature.  Steam causes more severe burning as compared to boiling water at 100°C due to the large amount of latent heat of vaporization.

On the other hand, boiling is the process by which a liquid turns into a gas or vapor at a temperature equal to or above its boiling point. In other words, when the liquid is heated to a temperature equal to or greater than its boiling point, it turns into a gas or vapor. The effect of humidity on the rate of evaporation is that if the air around the liquid is already humid, then the rate of evaporation will be slower because the air is already saturated with water molecules.
Latent heat of fusion is the amount of heat required to convert a solid into a liquid without any change in temperature. In other words, it is the amount of heat required to break the intermolecular forces between the molecules of a solid to convert it into a liquid.
Steam causes more severe burning as compared to boiling water at 100°C because steam contains a large amount of latent heat of vaporization. When steam comes in contact with the skin, it releases a large amount of latent heat of vaporization, which causes more severe burns as compared to boiling water at 100°C.

Evaporation is the process of turning a liquid into a gas or vapor at a temperature below its boiling point. Boiling, on the other hand, is the process of turning a liquid into a gas or vapor at a temperature equal to or above its boiling point. Humidity affects the rate of evaporation. Latent heat of fusion is the amount of heat required to convert a solid into a liquid. Steam causes more severe burning as compared to boiling water at 100°C due to the large amount of latent heat of vaporization.

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The most affected factor in people with sickle-cell anemia is the partial pressure of oxygen in the tissues.

Sickle-cell anemia is a genetic disorder that affects the structure of red blood cells. It causes the production of abnormal hemoglobin, known as hemoglobin S, which can distort the shape of red blood cells and make them rigid and prone to sticking together. This can result in reduced oxygen delivery to tissues and organs.

The most affected factor in people with sickle-cell anemia is the partial pressure of oxygen in the tissues. Due to the abnormal shape and reduced flexibility of sickle cells, they can get stuck in small blood vessels, leading to poor oxygen supply to tissues. This can cause tissue damage, pain, and other complications associated with sickle-cell anemia.

Other factors listed, such as the partial pressure of oxygen in air, the vol % of CO2 in blood, the partial pressure of CO2 in the lungs, the acidity of the blood plasma, the acidity inside the red blood cells, the Bunsen solubility coefficient for oxygen, and the chloride shift, may be influenced to some extent by sickle-cell anemia but are not the primary factors most affected by the condition.

In people with sickle-cell anemia, the partial pressure of oxygen in the tissues is the most affected factor. The abnormal red blood cells in sickle-cell anemia can cause reduced oxygen delivery to tissues, leading to various complications associated with the condition.

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Answer: 20 C

Explanation:

I would put it in 20 C because it is closer to the 20 C than the 30 C (it is below 25 C).

If we increase the temperature of the vessel to 450 K at constant volume, then the pressure inside the vessel be 15 atm.

The relationship between temperature and pressure for a fixed volume is described by Gay-law. According to this Law, the pressure of a gas is precisely proportional to its temperature for a fixed volume of the gas. It is written mathematically as P ∝ T, where P is the gas pressure.

T is the gas's temperature (in Kelvin).

P = kT, where k is the proportionality constant, and P / T is equal to k.

In this scenario, the vessel's temperature rises from 300 K to 450 K, its volume doesn't change, and its internal pressure rises.

If the temperature doubles, the pressure will also double.

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Wavelength (L) is calculated using: L = gT²/2π, here g=9.8 m/s2 and T is wave period in seconds.

Wavelength of a wave describes how long the wave is and the distance from the "crest" (top) of one wave to the crest of next wave is called wavelength. We can also measure from the "trough" (bottom) of one wave to trough of next wave and get the same value for the wavelength.

We measure wavelength in following ways:

Use photometer to measure the energy of wave.

Convert energy into joules (J).

Divide energy by Planck's constant, 6.626 x 10⁻³⁴, to get the frequency of  wave.

Divide speed of light, ~300,000,000 m/s, by frequency to get wavelength.

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The maximum number of moles of SO₃ that can be produced by the reaction of 2.0 mol of S with of O₂ will be 2, two moles.

Moles are the quantity of a material in per unit of solution. It is the SI unit of amount of a substance. The moles can be calculated by dividing the molecular weight of an object with the molecular mass of the substance.

The balanced reaction is

2SO₂ +O₂  →2SO₃

The ratio is 2:1

So if 2.0 mol of sulfur will reaction with 1 mole of oxygen there will be 2 moles of SO₃. The reaction clears the moles of SO₃ in the reaction.

Thus, maximum number of moles of SO₃ will be 2.

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Wegener suggested that the deserts of Africa were once covered in ice and that the striations were formed by the movement of the ice across the desert floor.

Glacier striations are grooves or scratches in the bedrock that have been created by a glacier sliding over the surface. They are typically found in areas where the ice has melted away, revealing the bedrock beneath.

Wegener suggested that the deserts were once wetter and lusher. He proposed that the climate has gradually changed over time, making the deserts arider. This is supported by evidence of ancient riverbeds and lakes in the Sahara Desert.

Glacier striations can be used to help researchers learn about the history of a particular glacier and the climate in the area where it is located. For example, the direction of the striations can indicate the direction the glacier was moving and the depth of the striations can give clues about how deep the glacier was.

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The general formula for an amino acid is RCH(NH2)COOH. The R group can vary among different amino acids, giving each amino acid its distinct properties.

Amino acids are organic compounds that serve as the building blocks of proteins. The general formula for an amino acid consists of four components: R, CH(NH2), COOH.

R represents the side chain or the variable group, which differs among different amino acids and gives each amino acid its unique properties. It can be a simple hydrogen atom (H) or a complex organic group.

CH(NH2) represents the amino group (-NH2) attached to the carbon (C) atom. It consists of one carbon atom bonded to three hydrogen atoms (CH3) and an amino group (NH2).

COOH represents the carboxyl group (-COOH) attached to the carbon atom. It consists of a carbon atom double-bonded to an oxygen atom (C=O) and a hydroxyl group (-OH).

The combination of the amino group and the carboxyl group on the same carbon atom forms an amino acid.

The general formula for an amino acid is RCH(NH2)COOH. This formula represents the structure of an amino acid, with R representing the side chain, CH(NH2) representing the amino group, and COOH representing the carboxyl group. The R group can vary among different amino acids, giving each amino acid its distinct properties.

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The first step is to calculate the molar flow rate of fuel, oxidizer, and product. This is done by dividing the mass flow rate (0.5 kg/s) by the molecular weight of each species (29 kg/kmol).

Molecular is a term used to describe the smallest units of matter. Molecules are made up of atoms and are held together by a chemical bond, which involves the sharing of electrons between atoms.

This gives us the following molar flow rates:

Fuel: 0.017 kmol/s

Oxidizer: 0.027 kmol/s

Product: 0.046 kmol/s

Next, we need to calculate the enthalpy change for the reaction. Since we are dealing with a single product species, the enthalpy change can be calculated using the following equation:

ΔH = (hf f o , + hf ox o , - hf o , pr) * n

Where:

hf f o , = Enthalpy of formation of fuel

hf ox o , = Enthalpy of formation of oxidizer

hf o , pr = Enthalpy of formation of product

n = Molar flow rate of product

Substituting the given values, we get the following:

ΔH = (-2000 + 0 - (-4000)) * 0.046 = 920 kJ/s

Now we can calculate the heat of reaction by multiplying the enthalpy change with the molar flow rate of the reactants. This gives us the following result:

Heat of reaction = (0.017 kmol/s * 920 kJ/s) + (0.027 kmol/s * 920 kJ/s) = 24.12 kJ/s

We can then calculate the temperature of the reactor by subtracting the heat loss (2000 W) from the heat of reaction and dividing by the total mass flow rate of the reactants (0.5 kg/s) multiplied by the specific heat capacity (1100 J/kg-K). This gives us the following result:

T = (24.12 kJ/s - 2000 W) / (0.5 kg/s * 1100 J/kg-K) = 436 K

Finally, we can calculate the residence time by dividing the volume of the reactor (0.003 m3) by the total mass flow rate of the reactants (0.5 kg/s). This gives us the following result:

Residence time = 0.003 m3 / 0.5 kg/s = 0.006 s

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The temperature in the reactor is approximately 10.74 K. and 0.006 s.  

The temperature in the reactor and the residence time, we need to solve the following set of equations:

dU = w + Q / m

Next, we need to find the rate of change of mass flow rate, which is given by:

dm = Fv - D

here Fv is the volume flow rate of reactants and D is the diffusion rate of the product.

Finally, we can use the above equations to find the temperature in the reactor and the residence time as follows:

Temperature in the reactor:

T = (dU / Q) / (m / cP)

here cP is the specific heat at constant pressure.

Residence time:

t = (m / D)

We can assume that the reactants have a volume flow rate of 0.5 kg/s and the product species has a volume flow rate of 0.001 kg/s. Therefore, the mass flow rate of the reactants is:

m = 0.5 kg/s * 0.002 m3/kg = 0.001 kg/s

The diffusion rate of the product can be calculated as:

D = k * (yox - yf) / (yf + yox)

here k is the reaction rate constant and (yox - yf) / (yf + yox) is the molar fraction of the product species.

Using the values of k, m, and (yox - yf) / (yf + yox) from the problem statement, we can calculate the diffusion rate of the product as:

D = 1 * (0.003 - 0.2) / (0.2 + 0.003)

= 0.00006 / 0.003

= 0.1833

Therefore, the residence time of the reactor is:

t = (0.001 kg/s / 0.1833 kg/mol) = 0.051 s

The temperature in the reactor is given by:

T = (dU / Q) / (m / cP)

here cP is the specific heat at constant pressure of the reactants, which is 1100 J/kg-K.

T = (w + Q / m) / (0.001 kg/s / 1100 J/kg-K) / (0.001 kg/s / 0.003 m3/kg)

= 10.74 K

Residence time = 0.003 m3 / 0.5 kg/s = 0.006 s

Therefore, the temperature in the reactor is approximately 10.74 K and 0.006 s.  

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Answer:

C

Explanation:

because 37 does not end with 5 or 0, so it'd be harder to see if the water temperature is accurate if your thermometer goes up by 5s or 10s. And using D, the one that goes up by 20s is out of the question, it'd be too difficult to read. Using a thermometer that goes up by 1s is just best because you can be positive when the water is at 37°C

Compounding personnel should contact the supplier to follow up on the delivery of the sterile isopropyl alcohol (IPA) bottles that did not arrive in the supply order. The personnel should request an estimated time of arrival and make sure to provide the exact details of the order.

If the sterile isopropyl alcohol (IPA) bottles did not arrive in the supply order, the compounding personnel should take the following steps:

It is important for the compounding personnel to take swift action in this situation to ensure that the necessary supplies are obtained and that compounding activities can continue without disruption.

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A) Solution B of 100 mM is more concentrated than Solution A of 0.5 mM.

B) Solution B of 3.7mg/dL is more concentrated than Solution A of 3.5mg/dL.

C) Solution A = 0% (w/v) and Solution B = 0% (w/v) equal concentrations.

D) Solution A of 10⁻³ M is more concentrated than Solution A of 10⁻⁵M.

E) Solution B of 12.3% (w/v) is more concentrated than Solution A of 12.23% (w/v)

In chemistry, concentration can be described as the abundance of components divided by the total volume of a solution. Several kinds of mathematical descriptions can be distinguished: mass concentration, number concentration, molar concentration, and volume concentration.

The concentration is defined as the kind of chemical mixture, but most frequently refers to solutes and solvents in solutions. The molar concentration has variants, such as osmotic concentration and normal concentration.

Molarity, molality, Normality, and weight/ volume percentage are also used to define the concentration of the solution.

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Answer:

Cifras significativas de 63,000

Result 63000

Sig Higos 2 (63000)

Decimales 0

Notación cientifica 6.3 × 104

Notación electrónica 6.3e+4

Palabras sesenta y tres mil

Answer:

filtration : eg mixture of chalk and water

sieving: eg mixture of solids of different sizes

distillation: eg mixture of garri and water

crystallization: eg mixture of salt and water

41.7% is the percentage by mass of hydrogen (H) in lithium hydroxide (LiOH). The solution mixture is frequently defined in terms of mass percentage.

The mass percent might be used to denote a degree. Furthermore, it defines the element during a specific mixing. The solution mixture is frequently defined in terms of mass percentage. It represents the amount of solute contained in a mass m of solution.

The quantity of solutes can be stated in terms of mass or moles. We will study the percent by mass formula with numerous solved numerical examples in this post.

Mass percent = (component’s mass ÷ total mass) x 100%

                      = (1/ 23.95)x 100%

                     = 41.7%

Therefore, 41.7% is the percentage by mass of hydrogen (H) in lithium hydroxide (LiOH).

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The molecule that has a central atom that is sp3 hybridized is CH3Cl. To determine the hybridization of an atom, we need to count the number of electron groups around the central atom.

In this case, the central atom in CH3Cl is carbon (C). CH3Cl has four electron groups around the central carbon atom: three sigma bonds with hydrogen (C-H bonds) and one sigma bond with chlorine (C-Cl bond). Each sigma bond counts as one electron group.

The four electron groups indicate that the carbon atom is sp3 hybridized. In sp3 hybridization, the carbon atom forms four sigma bonds with four electron groups, resulting in a tetrahedral geometry. Therefore, the correct answer is CH3Cl.

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Answer:

City B has the larger annual temperature range

Explanation:

This is correct option because generally the northern side of the equator is high in temperature than the southern hemisphere part.

Since the southern side of the equator or Southern Hemisphere, where city A resides will generally have higher altitude or rise, so this creates higher average temperature.

There is "no change" in the rate of an E1 reaction when you double the base.

Doubling the base concentration in an E1 reaction will not have a significant impact on the reaction rate. In an E1 reaction, the rate-determining step is the formation of a carbocation intermediate via the departure of a leaving group. This process is unimolecular and depends solely on the concentration of the substrate.

The role of the base in an E1 reaction is to act as a nucleophile in the subsequent step, which involves deprotonating the carbocation intermediate to form the product. Since the rate-determining step is not directly affected by the concentration of the base, doubling the base concentration will not change the overall reaction rate. Therefore, the best answer is "no change."

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