49. Which type of precursor is used
as reactant in intramolecular Claisen
condensation?
O One molecule with an ester end
O Two molecules of ester
O One molecule with two ester ends
O One molecule of ester and enolate​

Answer:

Chemistry teacher

Pharmaceuticals

Biochem/biotech

Materials science

Food chemist

Explanation:

Chemistry teaching

Teaching jobs in chemistry can range from teaching in public middle and high schools (bachelor’s degree required) to junior or community college (master’s degree required) to the university level (doctorate required). At the university level, you get to do research along with your teaching responsibilities.

Pharmaceutical/chemical sales

If you like chemistry but don’t enjoy being in the lab, then sales may be the job for you. Somebody has to sell all those chemicals and medicines, and buyers like to deal with somebody who knows their science.

Biochem/biotech

Biochemists and biotechnologists work in research developing new genetic tests, work in the genetic engineering (cloning) area, and are involved in the development of new drugs.

Materials science

Material scientists study the composition and structure of various materials with the goal of developing new products or improving existing ones.

Food chemist

Food and flavor chemists work in the research and development of new foods or keeping food fresh. Chemists test food additives and preservatives, develop new flavors, and analyze food for nutrient levels or the presence of contaminants.

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Answer:

4/15

Explanation:

we can write out an equation by doing (1/5 ÷ 3/4) and then switch the sign to multiplication and we can keep the first fraction the same (in this case 1/5) and then we flip the second fraction BUT when we flip the second fraction upside-down we have to change the symbol to multiplication (1/5x4/3)

then after that all we do is multiply the denominators and numerators :)

1 x 4 = 4

_______

5 x 3 = 15

answer would be 4/15

The interdependent relationship between advances in technology and scientific discoveries has enhanced our understanding of the universe. schooling, merchandising, and different multidisciplinary efforts by way of fostering higher information about the multidimensional nature of research.

Development in technological know-how and technology studies seeks to improve the techniques of technology and technology studies, Clinical expertise is used to create new technologies. New technology regularly allows scientists to explore nature in distinct ways and make new discoveries.

Technological know-how is the have a look at the natural world through a scientific approach i.e. collecting facts via a systematic procedure. And era is in which we observe science to create gadgets that can solve issues and perform distinct responsibilities. technology is literally the utility of science.

Society drives technological improvements and scientific inquiry. technology offers us a perception of what form of technology we should doubtlessly create and a way to create them, even as technology allows us to behave in addition to medical studies.

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XeF⁴ has a mοlar mass οf abοut 207.2886 g/mοl.

One mοle οf a material weighs οne mοlar mass. It is cοmputed by cοmbining the atοmic masses οf all the atοms in a mοlecule and is οften repοrted in grams per mοle (g/mοl). The mass οf an atοm in a chemical element is knοwn as its atοmic mass.

The atοmic masses οf the cοmpοnents, which are: can be added tο determine the mοlar mass οf XeF⁴ (xenοn tetrafluοride).

Atοmic mass οf xenοn (Xe) is 131.293 g/mοl.

Atοmic mass οf fluοrine (F) is 18.9984 g/mοl.

As a result, the fοrmula fοr calculating the mοlar mass οf XeF⁴ is:

Mοlar mass οf XeF⁴ = (1 x mοlar mass οf Xe) + (4 x mοlar mass οf F) = (1x 131.293 g/mοl) + (4 x 18.9984 g/mοl) = 207.2886 g/mοl (apprοx)

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Answer: the asnwer would be cycle

Explanation:cycle it

The town of Natrium, West Virginia, derives its name from the sodium produced in the electrolysis of molten sodium chloride(NaCl) mined from ancient salt deposits. The number of kilowatt-hours of electricity required to produce 5.50kg of metallic sodium from the electrolysis of molten NaCl(s) is 4.58  kWh when the applied emf is 5.00V

The reaction equation is given as:

Na⁺ +e⁻ ⇒ Na

So moles of Na equals moles of electrons used

So the number of moles of sodium can be calculated as:

number of moles = mass ÷ molar mass

Moles = 5500 g ÷ 23 g/mol (1 kg = 1000 g)

Number of moles = 239.13 moles

Q = n × F; where F represents the Faraday constant

Q = 239.13 moles × 96500 C

Q = 23,976,045 mol C

The relationship between electrical energy and Q is

E = Q x V

Now we can substitute the given value into the above formula and calculate the current value as follows:

E =  23,976,045 × 5 .50

E = 126,918,248 J

As 1 J = 2.77 × 10⁻⁷ kWh

For this reason;

126,918,248 J ÷ 2.77 × 10⁻⁷  kWh =4.58 kWh

From this we can conclude that 4.58  kWh of power is required to produce 5.50 kg of metallic sodium from the electrolysis of molten NaCl(s).

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Answer: The pressure in the container is 1949.5 torr when the volume is 7.20 liters and the temperature is 71.0 °C

Explanation: To solve this problem, we can use the combined gas law, which relates the initial and final conditions of pressure (P), volume (V), and temperature (T) for an ideal gas:

(P1 × V1) / T1 = (P2 × V2) / T2

where P1, V1, and T1 are the initial pressure, volume, and temperature, and P2, V2, and T2 are the final pressure, volume, and temperature.

We can plug in the given values:

P1 = 740.5 torr

V1 = 10.8 L

T1 = 23.0 °C + 273.15 = 296.15 K

V2 = 7.20 L

T2 = 71.0 °C + 273.15 = 344.15 K

(P1 × V1) / T1 = (P2 × V2) / T2

(740.5 torr × 10.8 L) / 296.15 K = (P2 × 7.20 L) / 344.15 K

Solving for P2:

P2 = (740.5 torr × 10.8 L × 344.15 K) / (296.15 K × 7.20 L)

P2 = 1949.5 torr

Therefore, the pressure in the container is 1949.5 torr when the volume is 7.20 liters and the temperature is 71.0 °C.

Explanation:

\(q = mc(t2 - t1)\)

\(q = 40 \times 2.44 \times (60 - 50)\)

\(q = 976 \: joules\)

To determine the freezing point we can apply the following formula that relates the molality to the freezing point of water:

Where,

m is the molality

Kf is the freezing point of water

DeltaTf= Freezing point

We replace the known data:

So, the freezing point of the solution will be 1.49°C

Answer: Ecosystem services are the flows of benefits which people gain from natural ecosystems, and natural capital is the stock of natural ecosystems from which these benefits flow. So, a forest is a component of natural capital, while climate regulation or timber might be the ecosystem service it provides.

Answer:

56.04 g

Explanation:

Step 1: Given data

Moles of nitrogen (n): 2 mol

Step 2: Calculate the molar mass of nitrogen (M)

The molar mass of the molecule is the sum of the masses of the molecules that form it.

mN₂ = 2 × mN = 2 × 14.01 g/mol = 28.02 g/mol

Step 3: Calculate the mass corresponding to 2 moles of nitrogen

We will use the following expression.

m = n × M

m = 2 mol × 28.02 g/mol = 56.04 g

Answer:

Option b.

Al < B < P < N

Explanation:

Electronegativity is the capacity of an atom to attract electrons.

Usually, if we look at the periodic table, the elements in the left are the ones with the least electronegativity, and as we go to the right, the electronegativity increases (this is not really exact)

There are a lot of tables of electronegativity that can be used here, we can find that:

element:    electronegativity:

    N                         3.04

    B                          2.04

    P                          2.19

    Al                          1.61

So, the order from least to greatest is:

Al, B, P, N

Then the correct option is:

b: Al < B < P < N

The limiting reactant is CH4. This is because the number of moles of CH4 is 4.44mol, while the number of moles of water is 0.86mol. The number of moles of hydrogen produced from the reaction is 8.88mol.

Hydrogen is a chemical element with the symbol H and atomic number 1. It is the most abundant element in the universe, making up about 75% of the universe's elemental mass. Hydrogen is a colorless, odorless, and tasteless gas, which is the most basic and simplest of all elements. It is a highly flammable, light, and combustible gas and burns with a pale blue flame. Hydrogen is a component of water, which is composed of two atoms of hydrogen and one atom of oxygen. In addition, it is found in many organic compounds and is used in the production of ammonia, methanol, and hydrochloric acid

This means that there are not enough moles of water to completely react with the CH4. Therefore, the limiting reactant is CH4.

The number of liters of hydrogen produced from the reaction of 80.0 g of CH4 and 16.3 g of water is 16.3 L. This is because the number of moles of hydrogen produced is 8.88mol, and at STP the volume of 1mol of a gas is 22.4L. Therefore, the volume of 8.88mol of hydrogen is 8.88 x 22.4L = 197.3L. Since the total volume of gas produced is 197.3L and 16.3g of water was used in the reaction, the amount of hydrogen produced is 16.3L.

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The volume of 12 gas forms when 21 L Cl2 react at STP is 21 L.

To determine the volume of 12 gas (I assume you mean I2 gas) formed when 21 L of Cl2 reacts at STP (standard temperature and pressure), we need to use the ideal gas law equation.

The ideal gas law equation is given by:

PV = nRT

Where:

P = pressure

V = volume

n = number of moles

R = ideal gas constant

T = temperature

At STP, the pressure is 1 atm, and the temperature is 273.15 K.

From the balanced equation, we can see that the molar ratio between Cl2 and I2 is 1:1. So, if 21 L of Cl2 reacts, it will produce an equal volume of I2 gas.

Given that the volume of Cl2 is 21 L, we can assume the volume of I2 gas formed will also be 21 L.

Therefore, the volume of I2 gas formed is 21 L.

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Answer:

2 is correct

Explanation:

My friend for you this answer

we would need 2625.13 grams (or 2.62513 kilograms) of NaCl.

To calculate the mass of NaCl required to produce a 26.4 mol/L solution with a 1.7 L volume, we need to use the formula that relates the mass of solute, moles of solute, and molarity:Molarity (M) = moles of solute / liters of solution Rearranging this formula, we get:moles of solute = Molarity (M) x liters of solutionWe can use this formula to find the moles of NaCl needed:moles of NaCl = 26.4 mol/L x 1.7 L = 44.88 molNow, we can use the molar mass of NaCl to convert from moles to grams. The molar mass of NaCl is 58.44 g/mol:mass of NaCl = moles of NaCl x molar mass of NaClmass of NaCl = 44.88 mol x 58.44 g/mol = 2625.13 gTo produce a 26.4 mol/L solution with a 1.7 L volume.

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Answer:

It is more environmentally friendly. Nuclear power generates clean energy by bombarding uranium with neutrons as opposed to burning fossil fuels. Nuclear reactors do not produce direct carbon dioxide emissions, and any indirectly produced emissions have negligible impacts on the environment.

It can create jobs. The nuclear industry supports nearly half a million jobs in the United States and contributes an estimated $60 billion to the U.S. gross domestic product each year. U.S. nuclear plants can employ up to 700 workers with salaries that are 30% higher than the local average. They also contribute billions of dollars annually to local economies through federal and state tax revenues.

Answer:

1. Nuclear energy is relatively cheap to produce energy from and have low operating costs.

2. It's reliable and emits zero carbon emissions and high energy density.

Hope this helps.

Answer:

During the early Paleozoic Era, the Earth's surface was very different from what it is today. The continents were arranged differently, forming one large supercontinent called Pangea. This landmass was surrounded by a single large ocean called Panthalassa. The climate was much warmer and wetter than it is today, with no ice caps at the poles.

The first land plants, known as bryophytes, appeared during the early Silurian Period, around 430 million years ago. These plants were small and simple, lacking roots and vascular tissue. They grew in damp environments, such as along the edges of lakes and streams. They were important in the development of soils and in the colonization of land by other organisms, such as insects and other arthropods.

Answer:

You must get a solution of HCl that has a higher molarity than 8.0M . Check the exact molarity by titrating against a standard NaOH solution. Measure out 815.5 mL of the 9.18 M HCl solution and dilute to final volume = 1000 mL with distilled water.

Explanation:

It is very difficult to calculate how to make 8M HCl in 1000 mL water

I will calculate : How to make 8 M HCl in 1000 mL SOLUTION.

NOTE : IMPORTANT: in 1000 mL SOLUTION

You must get a solution of HCl that has a higher molarity than 8.0M . Check the exact molarity by titrating against a standard NaOH solution.

Say that the molarity = 9.18M

Now calculate the volume required:

M1V1 - M2V2

9.18 * V1 = 8 M* 1000 mL

V1 = 8 M * 1000 mL / 9.18M

V1 = 871.5 mL

Measure out 871.5 mL of the 9.18 M HCl solution and dilute to final volume = 1000 mL with distilled water.

One mole of radiant energy will supply 6.02 x 10^23 photons.

The number of photons is calculated by dividing the overall energy of a pulse by the energy of one photon included inside the pulse.

As a result, an electromagnetic energy particle is known as a photon. Photons have no mass, thus they move at the same rate as light.

we need to first calculate the total energy in one mole of photons,

By combining the energy per photon with Avogadro's number (6.022 x 1023), one may determine the energy of a mole of photons:

Energy per mole of photons = Energy per photon x Avogadro's number

we can calculate the energy per mole of photons:

Energy per mole of photons = 3.37 × 10−19 J x 6.022 x 10^23

Energy per mole of photons = 2.03 x 10^5 J/mol

Number of photons in one mole = Energy per mole of photons / Energy per photon

Number of photons in one mole = 2.03 x 10^5 J/mol / 3.37 × 10−19 J

Number of photons in one mole = 6.02 x 10^23 photons/mol

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One time explanation of one observation is a hypothesis.

Whenever, an assumption is made juts by observation and without proper testing then that is referred as an hypothesis.

For example- If my friend is late, so I might assume that he or she must have been stuck in traffic. So, this assumption is not tested yet and is made based on my observation. So, this is a hypothesis.

Whenever, a conclusion is given after several experiments and testing after observing something in science is referred as scientific theory.

For example- Atomic theory given by Dalton was based on several experiments. However, theories can also be proved wrong as Dalton's theory was proved wrong later on my JJ Thomson.

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The amount of work that has been done by the man would be =1,102.5Nm

To calculate the amount of work that was done by the man, the formula that should be used would be given below as follows:

Work done = Force × distance

But force = mass × acceleration

mass = 75kg

acceleration = 9.8m/s²

Force = 75×9.8 =735N

Work done = 735× 1.5 = 1,102.5Nm

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The mass of a substance with given number of molecules can be calculated by first finding the number of moles in the substance as follows:

No. of moles = no of molecules ÷ Avogadro's number

Mass of these substances can be calculated by multiplying the number of moles by their molar mass as follows:

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Answer:

One of the properties of acids is their ability to donate protons (H+ ions) when dissolved in water

Explanation:

One of the properties of acids is their ability to donate protons (H+ ions) when dissolved in water. This property is referred to as acidity. Acids can also be described by the presence of positively charged hydrogen ions (H+) and a pH value below 7. Other properties of acids include their corrosive nature, sour taste, and ability to react with bases to form salts and water in a process called neutralization.

Answer:

In longhand notation the electron configuration is

1s² 2s² 2p6 3s¹

In Noble gas configuration

[ Ne ] 3s¹

Hope this helps you.

Answer:

2. 1s22s22p63s1

Explanation:

Answer

Part A - Physical change

a) a change of state

d) a change that can be measured without reference to other substances

Part B - Chemical change.

b) a change in reactivity.

c) results in a substance different from the original.

Explanation

Physical changes are changes affecting the form of a chemical substance, but not its chemical composition. Examples of physical change include changes in the size or shape of matter. Changes of state, for example, from solid to liquid or from liquid to gas, are also physical changes. Some of the processes that cause physical changes include cutting, bending, dissolving, freezing, boiling, and melting.

Chemical changes cause a substance to change into an entirely substance with a new chemical formula or chemical changes occur when a substance combines with another to form a new substance. Examples are burning of any substance, rusting of iron.

Part A - Physical change

a) a change of state

d) a change that can be measured without reference to other substances

Part B - Chemical change.

b) a change in reactivity.

c) results in a substance different from the original.

0.518 mol L⁻¹ NaCl concentration results when 244 mL of a 0.750 M NaCl solution is mixed with 437 mL of a 0.390M NaCl solution.

Moles of NaCl  in 244ml = 244* 10⁻³L * 0.750 mol L⁻¹

= 183 * 10⁻³ mol

Moles of NaCl in 437ml = 437*10⁻³L * 0.390 mol L⁻¹

=170.43* 10⁻³ mol

Since we must consider the volumes to be additive when these solutions are mixed, we have the following concentration with respect to  NaCl

Concentration =  ( 0.183+ 0.170)mol/ (244+437)*10⁻³L

= 0.353 mol/681*10⁻³

= 0.518 mol L⁻¹

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