Substance A has the following properties.
mp at 1 atm: - 220.°C bp at 1 atm: 85°C
ΔHfus : 180. J/g ΔHvap : 500. J/g
Csolid : 1.0 J/g?°C C liquid : 2.5 J/g?°C
Cgas : 0.5 J/g?°C
At 1 atm, a 25-g sample of A is heated from 240.° C to 100.°C at a constant rate of 450. J/min. (a) How many minutes does it take to heat the sample to its melting point?

Answer:

C. 6.35 cm

Explanation:

The mode is the value that appears most frequently in the data. From the given table, we can see that 6.35 cm appears twice, which is more than any other value. Therefore, the mode is 6.35 cm.

The velocity profile of an incompressible fluid flowing down a vertical cylindrical pipe can be derived using the Navier-Stokes equation under certain assumptions. With a pipe length of 6 m, diameter of 5 cm, friction factor of 0.01, and a constant flow rate of 3 m³/hr, we can calculate the pressure drop using the given information.

a) To derive the velocity profile of the fluid in the pipe, we can start with the Navier-Stokes equation, which describes the motion of a fluid. Under the assumption of laminar flow and incompressibility, the equation simplifies to:

dP/dz = (32μLQ) / (πR^4)

where dP/dz is the pressure gradient, μ is the dynamic viscosity of the fluid, L is the pipe length, Q is the volumetric flow rate, and R is the pipe radius. By integrating this equation, we can obtain the velocity profile of the fluid.

b) To calculate the pressure drop, we need to convert the flow rate from m³/hr to m³/s. Given that 1 m³/hr is equal to 1/3600 m³/s, the flow rate becomes Q = 3 / 3600 m³/s. By substituting the values of μ, L, Q, and R into the derived equation, we can calculate the pressure gradient. Finally, the pressure drop can be obtained by multiplying the pressure gradient by the length of the pipe (6 m).

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Metallic Minerals will be minerals in which metal components are available in their crude structure. Non-metallic minerals don't contain any metal substances in them. At the point when metallic minerals are dissolved another item is shaped. Non-metallic minerals are frequently discovered installed in youthful overlay mountains and sedimentary rocks.

In this case, there is no HF left to react, so [HF] = 0 MThus, pH = pKa + log [A-]/0 pKa = -log (3.5 × 10⁻⁴) = 3.455pH = 3.455 + log [0.2771 mol/1.7 L]pH = 3.455 - 0.795pH = 2.66. Therefore, the pH of the resulting solution is 2.66.

Initial moles of HF added = 2.26 mol. Concentration of NaF solution = 0.163 M. Final volume of solution = 1.7 LKa of HF = 3.5 × 10⁻⁴. Firstly, let us determine the initial amount of NaF moles,

Initial moles of NaF = Molarity × Volume= 0.163 M × 1.7 L= 0.2771 molNext, let us calculate the moles of NaF that react with HF, From the balanced chemical equation,1 mole of HF reacts with 1 mole of NaF. Thus, 2.26 moles of HF react with 2.26 moles of NaF.

After the reaction, the remaining moles of NaF = initial moles of NaF - moles of NaF reacted= 0.2771 mol - 2.26 mol= -1.9829 mol. Since the result is negative, it indicates that the entire NaF has reacted and the HF is in excess. Thus, moles of HF left = initial moles of HF - moles of HF reacted= 2.26 mol - 2.26 mol= 0 mol

Concentration of HF after reaction= moles of HF remaining/ final volume= 0 mol / 1.7 L= 0 M.

Using the Henderson-Hasselbalch equation, pH = pKa + log [A-]/[HA]Where A- is the fluoride ion and HA is the HF species.In this case, there is no HF left to react, so [HF] = 0 MThus, pH = pKa + log [A-]/0 pKa = -log (3.5 × 10⁻⁴) = 3.455pH = 3.455 + log [0.2771 mol/1.7 L]pH = 3.455 - 0.795pH = 2.66Therefore, the pH of the resulting solution is 2.66.

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Answer:

The population of hawks would decrease cause the snake is decreasing

Explanation:

although i would think hawks could eat rabbits but it doesn't ask you that so its haws decreasing

Answer: The population of Hawks will decrease.

Explanation:  When the population of one species decreases suddenly, as when a disease strikes the population, the populations higher in the food chain also decrease due to a loss in food supply. In this case the hawk population decreases because there are suddenly fewer snakes to eat. The species below the diseased species in the food chain increase because there are fewer predators. In this case, the rabbit population increases because there are fewer snakes to eat them.

Given :

To Find :

Solution :

Formula for density is :

\(\boxed{\sf{Density\ =\ \dfrac{Mass}{Volume}}}\)

⇒0.789 = Mass/1500

⇒ Mass = 0.789 * 1500

⇒ Mass = 1,183.5 g

Hence, Mass of ethyl alcohol is 1,183.5 g.

Answer:

b) Exothermic

Explanation:

Exothermic reaction:

The type of reactions in which energy is released are called exothermic reactions.

In this type of reaction energy needed to break the bonds are less than the energy released during the bond formation.

For example:

Chemical equation:

C + O₂   →  CO₂

ΔH = -393 Kj/mol

it can be written as,

C + O₂   →  CO₂ + 393 Kj/mol

An aqueous solution of NaCl freezes at -1.9 oc. and the solution will boil at 100.53 °C.

To calculate the boiling point of a solution, we can use the following formula: ΔTb = Kb × molality

where ΔTb is the boiling point elevation, Kb is the molal boiling point elevation constant (which is given as 0.52 °C/m for water), and molality is the molal concentration of the solution, which is defined as the moles of solute per kilogram of solvent.

We can first calculate the molality of the NaCl solution using the freezing point depression formula:

ΔTf = Kf × molality

where ΔTf is the freezing point depression (which is equal to the difference between the freezing point of the pure solvent and the freezing point of the solution), Kf is the molal freezing point depression constant for water (which is equal to 1.86 °C/m), and molality is again the molal concentration of the solution.

From the given data, we know that the freezing point depression is ΔTf = (0 °C) - (-1.9 °C) = 1.9 °C. Therefore:

1.9 °C = 1.86 °C/m × molality

molality = 1.9 °C / 1.86 °C/m = 1.02 m

Now that we know the molality of the solution, we can use the boiling point elevation formula to calculate the boiling point of the solution:

ΔTb = Kb × molality

ΔTb = 0.52 °C/m × 1.02 m = 0.53 °C

The boiling point elevation is 0.53 °C, which means that the boiling point of the NaCl solution is:

Tb = 100 °C + ΔTb = 100.53 °C

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The change in entropy of the cube-lake system as the ice cube comes to thermal equilibrium with the lake is zero.

The entropy change of a cube-lake system as the ice cube comes to thermal equilibrium with the lake is calculated. Given data:

Mass of the ice cube = 17 g

Temperature of ice cube = -27°CTemperature of the lake = 61°C Specific heat of ice = 2220 J/kg⋅

K

The change in entropy of the cube-lake system as the ice cube comes to thermal equilibrium with the lake can be calculated using

ΔS = Q/T where Q is the heat absorbed or released during the process,

and T is the temperature at which the process occurs.

It is given that the ice cube is placed in a lake whose temperature is 61°C, which is greater than the melting point of ice and the ice cube will melt to the liquid state. However, the temperature of the lake is so high that the heat absorbed by the ice cube in melting does not cause any significant change in temperature of the lake.Therefore, it can be concluded that the process of ice melting is adiabatic. In an adiabatic process, ΔQ = 0, and ΔS = 0. Thus, the change in entropy of the cube-lake system as the ice cube comes to thermal equilibrium with the lake is zero. Answer: ΔS = 0.

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For outside treatment:

The cost is a fixed $15,000 per year for the entire 9-year period.

Therefore, the EUAC for outside treatment is simply $15,000.

Comparing the EUAC values, we find that the EUAC for in-house treatment is approximately $6,329, while the EUAC for outside treatment is $15,000.

To calculate the equivalent uniform annual cost (EUAC) of each alternative and determine the most economical option, we need to analyze the costs over the 9-year period.

For in-house treatment:

The cost in the first year is $30,000, and the cost declines by $3,000 each year. We can use the arithmetic gradient formula to calculate the equivalent uniform annual cost.

Using the formula for an arithmetic gradient, the EUAC for in-house treatment can be calculated as follows:

EUAC = C - (G/A) * (1 - (1 + i)^(-n))

Where:

C = Initial cost = $30,000

G = Gradient (decrease per year) = -$3,000

A = Annuity factor (obtained from the interest and annuity table for discrete compounding) for 9 years at 8% MARR = 6.71008 (rounded)

i = Interest rate = 8% = 0.08

n = Number of years = 9

Substituting the values into the formula:

EUAC = $30,000 - (-$3,000/6.71008) * (1 - (1 + 0.08)^(-9))

EUAC ≈ $6,329 (rounded)

For outside treatment:

The cost is a fixed $15,000 per year for the entire 9-year period.

Therefore, the EUAC for outside treatment is simply $15,000.

Comparing the EUAC values, we find that the EUAC for in-house treatment is approximately $6,329, while the EUAC for outside treatment is $15,000.

Since the EUAC for in-house treatment is lower, it is the more economical alternative for processing waste liquids.

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we can accurately determine the freezing point depression using the mentioned formula ∆T = K_f * m.

To calculate the freezing point depression, we would need the cryoscopic constant for the solvent used, as well as the mass of the solvent in which the protein is dissolved

To determine the expected freezing point depression when 1.00 g of a protein with a molar mass of approximately 14,000 u, we need to calculate the number of moles of protein and then use the formula for freezing point depression.

First, we convert the mass of the protein to moles using its molar mass:

Number of moles of protein = mass of protein / molar mass of protein

Molar mass of protein = 14,000 g/mol (approximated)

Number of moles of protein = 1.00 g / 14,000 g/mol = 7.14 x 10^-5 mol

Next, we need to determine the freezing point depression using the formula:

∆T = K_f * m

Where:

∆T is the freezing point depression

K_f is the cryoscopic constant (specific to the solvent)

m is the molality of the solute (in mol solute per kg solvent)

The cryoscopic constant varies depending on the solvent used. For water, the cryoscopic constant (K_f) is approximately 1.86 °C/m.

Since the question does not specify the solvent, we cannot provide an accurate value for the expected freezing point depression without knowing the specific cryoscopic constant.

To calculate the freezing point depression, we would need the cryoscopic constant for the solvent used, as well as the mass of the solvent in which the protein is dissolved (needed to calculate molality, m). With these values, we can accurately determine the freezing point depression using the formula mentioned above.

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Answer:

Energy in the ocean and the atmosphere

Explanation:

Hope this helps!

Answer:

Calculating Atomic Mass

Change each percent abundance into decimal form by dividing by 100. Multiply this value by the atomic mass of that isotope. Add together for each isotope to get the average atomic mass.

Explanation:

have a nice day

Answer:

Zirconium

Explanation:

Given that,

Mass number = 92

No of neutrons = 52

Mass number is the sum of the number of protons and neutrons. We can find the number of protons.

92 = 52 + P

P = 40

Atomic number is equal to the number of protons. It means that the atomic no of the element is 40. The element is Zirconium whose atomic number is 40 and mass number is 92.

Answer:

He could separate the mixture through filtration and fractional crystallization. Ethanol can also be added in order to remove salt.

Answer:

Pb(C2H3O2)2 + KI ----> PbI2 + KC2H3O2

Explanation:

all the numbers are written as subscripts

The relationship between Keto and enol tautomers  is the interconversion between a keto group and an enol group. and curcumin can exist in both forms.

Keto-enol tautomerism is a type of isomerism in which a molecule exists in two forms, the keto form and the enol form, that are in equilibrium with each other.

For example: Curcumin, a natural polyphenol found in turmeric, can exist in both keto and enol forms due to the presence of an α,β-unsaturated carbonyl group.

Tautomers, are interconvertible by the transfer of a hydrogen atom and a double bond. In the keto form, the molecule contains a carbonyl group (C=O), while in the enol form, the molecule contains an alkene (-C=C-OH) and an alcohol (-OH) group. Curcumin, which is the main active ingredient in turmeric, is an example of a compound that can exist in both the keto and enol forms. The keto form of curcumin is more stable and is the predominant form in solid-state, while the enol form is more reactive and can undergo various reactions.

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Unsaturated solution: a solution in which more solute can be dissolved.

Explanation:

Salt dissolved in water or even sugar dissolved in water is an unsaturated solution if the quantity of dissolved salt/sugar is below the saturation point.

unsaturated solution: a solution in which more solute can be dissolved.

Explanation:

A solution in which the maximum amount of solvent has been dissolved. Any more solute added will sit as crystals on the bottom of the container.

The single replacement reaction is that in which one element is substituted for another element but in the same compound.

A single replacement reaction is also known as a single displacement reaction. The single replacement reaction is defined as the reaction in which one element is substituted for another element in a compound. In the beginning, the starting element is always will be pure metal, such as pure zinc metal.

Identification:

We can determine the single replacement reaction when one element replaces another element in the same compound. This kind of reaction is represented by: A + BC → B + AC.

Determination:

The single replacement reaction can be determined when a less reactive element can be replaced by a more reactive element in a compound.

So we can conclude that one element is replaced by another element in the single replacement reaction.

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Answer:

Explanation:

The molecular formula is the true chemical formula of a covalent molecular compound, and a multiple of the empirical formula. We can use the molar mass, along with the molar empirical mass, determined from the empirical formula, to determine the molecular formula of the compound.

Using, the percentage composition of each element, we can say: In each 100g of the compound, there is 49.47g (C), 5.201g (H), 28.84g (N), and 16.47g (O).

Therefore, we can now find the number of moles of each element, in 100g of compound. number of moles (n) = mass present (m) ÷ molar mass (M). Molar mass can be found using a standard IUPAC Periodic Table.

n(C) = m/M = 49.47/12.01 = 4.1191 mol

n(H) = m/M = 5.201/1.008 = 5.1597 mol

n(N) = m/M = 28.84/14.01 = 2.0585 mol

n(O) = m/M = 16.47/16.00 = 1.0293 mol

Since the empirical formula is one in which the proportions of each element are expressed in the simplest mole ratio, therefore:

C : H : N : O = 4.1191 : 5.1597 : 2.0585 : 1.0293

Divide each ratio by 4.1191 =

1 : 1.00985 : 0.4997 : 0.249, which is approximately equal to:

1 : 1 : 0.5 : 0.25 = 2 : 2 : 1 : 0.5 = 4 : 4 : 2 : 1

Therefore, empirical formula = C₄H₄N₂O.

Using empirical formula, we can calculate molar empirical mass, which is found by summing the molar atomic weights.

molar empirical mass = 4(12.01)+4(1.008) + 2(14.01) + 16.00 = 96.092.

The molar empirical mass is double the molar mass, and therefore, molecular formula must be half the empirical formula.

Therefore, molecular formula = C₂H₂NO

To keep burning, fires require oxygen. Carbon dioxide is used in certain fire extinguishers to put out flames. Explanation: Because magnesium is higher on the reactivity scale than carbon, it is more reactive and eliminates oxygen from carbon dioxide (to give carbon and magnesium oxide).

The density of carbon monoxide gas at 20°C and 98 kPa is 1.145 g/L.

The ideal gas law is PV = nRT

where P is the pressure, V is the volume, n is the number of moles of gas, R is the gas constant, and T is the temperature in kelvin.

To find the density of carbon monoxide gas at 20°C and 98 kPa, we can use the ideal gas law to find the number of moles of gas in 1 L of gas at these conditions and then divide the mass of 1 mole of gas by the number of moles to get the density.

First, we need to convert the temperature to kelvin:

20°C + 273.15 = 293.15 K

Rearranging the ideal gas law, we get:

n = PV/RT

We can assume that the volume is 1 L, so:

n = (98 kPa)(1 L) / [(0.0821 L·atm/mol·K)(293.15 K)] = 0.0413 mol

The molar mass of carbon monoxide is 28.01 g/mol, so the mass of 0.0413 mol is:

0.0413 mol x 28.01 g/mol = 1.152 g

Therefore, the density of carbon monoxide gas at 20°C and 98 kPa is:

1.152 g / 1 L = 1.145 g/L

What is density?

Density is a physical property of matter that relates to the amount of mass per unit of volume of a substance. It is typically expressed in units such as grams per cubic centimeter (g/cm³) or kilograms per cubic meter (kg/m³).

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brittle metal would experience this type of failure

Glass, ceramic, graphite, and some alloys with very low plasticity are examples of brittle materials. In these materials, cracks can start without plastic deformation and quickly progress to brittle breakage. It is a steel-gray, lightweight metal called beryllium. It is also highly brittle, which means that it fractures easily when under stress but does not typically distort before it does so (similar to glass or ceramic). Beryllium is a naturally occurring element found in over 100 different minerals and has a wide range of modern-day applications. Cast iron has a rough feel and is more brittle because it includes 2% to 3.5% carbon. Despite being made of alloyed metals, carbon steel lacks other alloying components, hence despite being an alloy, it is not classified as an alloy.

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Answer:

Some examples of physical properties are:

color (intensive)

density (intensive)

volume (extensive)

mass (extensive)

boiling point (intensive): the temperature at which a substance boils.

melting point (intensive): the temperature at which a substance melts.

Explanation:

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The ion with the smallest number of unpaired electrons is \(Ni^{2+}\)

The number of unpaired electrons in the d-orbitals of transition metal ions is calculated using a simple method. In an octahedral crystal field, . In a tetrahedral crystal field, the opposite is true. The number of unpaired electrons is equal to the number of electrons in the eg orbitals subtracted from two.  \(Ni^{2+}\)has two electrons in the eg orbitals, resulting in no unpaired electrons.

Because the number of electrons is greater, there is a greater chance of having unpaired electrons, resulting in paramagnetism. The ion with the smallest number of unpaired electrons between \(Ni^{2+}\) and \(Cr^{+}\) is \(Ni^{2+}\). To understand why, let's examine the electron configurations of both ions.

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Explanation:

Antoine Lavoisier is the answer

Answer:

Antoine Lavoisier is the father of chemistry

Explanation:

Antoine-Laurent de Lavoisier, also Antoine Lavoisier after the French Revolution, was a French nobleman and chemist who was central to the 18th-century chemical revolution and who had a large influence on both the history of chemistry and the history of biology.

The correct option is -4.  The net charge of an atom with 5 protons 5 neutrons and 1 electron is -4.

The net charge of an atom with 5 protons, 5 neutrons, and 1 electron is O-1 (negative one). This is because the number of protons (+5) determines the atomic number and the number of electrons (-1) determines the overall charge of the atom. Since there is only 1 electron and it is negative, it cancels out one of the protons making the overall charge negative.

To determine the net charge of an atom, you need to consider the number of protons and electrons, as they carry positive and negative charges, respectively. Neutrons do not carry any charge. Here's a step-by-step explanation:
1. Identify the number of protons: 5 protons
2. Identify the number of electrons: 1 electron
3. Calculate the net charge: (Number of protons) - (Number of electrons)
In this case, the net charge is: (5 protons) - (1 electron) = -4

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By using the ideal gas law to get volume we have"

Where v is volume, T is temperatute, n is number of moles, R is the molar gas constant and P is pressure. At STP P= 101,325 Pa, T= 273.15 K and R= 8.314 J/mol K

We must first convert mass to moles:

By substituting this value into the ideal gas law we have:

1.9502e-6L of H2 gas reacted at STP