the enrgy profiles for four different reactions are shown below the scales are the same for each. which reaction is the most exothermic

There will be around 10 billion holes in the valence band, whereas the temperature and the applied electric fields all influence how the electrons travel within a semiconductor.

a. At room temperature, the number of holes in the valence band is roughly equal to the number of electrons in the conduction band in an inherent semiconductor like silicon (Si). This is because of the charge neutrality principle, according to which the material's overall charge is balanced. As a result, the valence band would also have roughly 10 billion holes.

b. Conduction band electrons do not constantly seek lower energy levels. A bandgap exists in an intrinsic semiconductor between the energy levels of the conduction band and the valence band. Compared to the valence band, electrons in the conduction band have greater energy levels, and they are not capable of moving spontaneously to lower energy levels. The temperature, the presence of impurities or defects, and the applied electric fields all influence how the electrons travel within a semiconductor.

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Complete Question:

At room temperature in a cubic centimeter of Si there will be about 10 billion electrons in the conduction band.

a. How many holes are in the valence band?

b. If electrons are constantly seeking lower value how are they governed ?

Dalton's law of partial pressures states that the total pressure of a mixture of gases is equal to the sum of the partial pressures of the component gases

Partial pressures can be calculated in one of two ways: 1) To determine the individual pressure of each gas in a mixture, use PV = nRT. 2) Determine the proportion of pressure from the total pressure that may be assigned to each individual gas by using the mole fraction of each gas.

Pressure overall is 98.8 kPa. Each gas's partial pressure relates to how many moles of that gas there are in the combination. Therefore, the partial pressure of each gas is equal to (0.500/0.750) x 98.8 = 65.9 kPa for H2 (increased)

Because pressure and force are connected, you can determine one using the physics formula pressure = force/area if you know the other.

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a. The mean rate of reaction after 15 seconds is 1.03 g/second.

b. After 60 seconds, the reaction has gone to completion.

The rate of reaction is the rate at which product molecules are formed or the rate at which reactant molecules disappear.

The rate of reaction measures the time it takes for 1 mole of reactant to be converted to the product or the time it takes for one mole of product to be formed from reactants.

Mathematically;

The rate of the given reaction is determined as follows:

a. mean rate of reaction after 15 seconds = (13 + 18) / (10 + 20)

mean rate of reaction after 15 seconds = 1.03 g/second

B, the reaction goes to completion when the mass of CO₂ produced remains constant or unchanged.

The mass of CO₂ produced remains constant after 60 seconds.

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Answer:

Alkaline Earth Metals

Explanation:

Answer:

The formula for sulphite isSO3(2-).

Answer:

D

Explanation:

magnesium always lose 2 electrons

Answer:

C12H24

Explanation:

The molar mass of the CH2 unit is 14 g/mole.  The final molecule has multiples of CH2 so that it's molar mass is 168 g/mole.

(168 g/mole molecule)/(14 g/mole Unit) = 12 Units

12 CH2 units would make the molecualr formula:  C12H24

This is more than one structure that has this formula:  Cyclododecane and 1-Dodecene.

Magnetic, electric, and gravitational fields are a few examples of the forces that pull you toward the center of the earth.

Every mass of stuff has an area surrounding it where other bodies may feel its gravitational pull.A gravitational field is the name given to this area of space.The gravitational field has direction, just like other electromagnetic fields like the electric and magnetic fields.It's a vector field as a result.

field is a zone in physics where each point is connected to a physical quantity.The quantity could be a vector, such as in the case for fields like the gravitational field, that are linked to a force, or it could be a number, such as in the case of scalar fields like the Higgs field.

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Answer:

A. It is exothermic

Explanation:

Combustion is a chemical reaction in which a substance combines with oxygen present in air to produce carbon (iv) oxide and water as well release  heat and light energy.Combustion is an exothermic process.

An exothermic reaction releases energy in the form of heat to the surroundings. The energy required to break bonds in the reactants is less than the energy required to form new bonds in the products in an exothermic reaction.

From the given options;

A. It is exothermic is determinable since the reaction is a combustion reaction

B. The bond making energy is more than 600 kJ is not certain because the mass of the wood being burnt is not given. Also, wood is not composed of a specific element that would be taking part in the reaction, rather it is composed of various substances.

C. It is endothermic. is wrong because combustion of wood is exothermic.

D. The bond breaking energy is more than 600 kJ is not certain because the mass of the wood being burnt is not given. Also, wood is not composed of a specific element that would be taking part in the reaction, rather is composed of many substances.

The ion that has 26 protons, 28 neutrons, and 24 electrons is Iron (Fe) (option c).

An element can be determined by the number of protons in the nucleus of its atom. The number of protons present in an atom is referred to as the atomic number of the element.

This means that the number of protons in an atom is unique to a specific element.

Iron (Fe) has 26 protons in the nucleus of its atom.

Therefore, an ion with 26 protons is an ion of the element iron (Fe).

Magnesium (Mg) has 12 protons, Chromium (Cr) has 24 protons, Xenon (Xe) has 54 protons and Nickel (Ni) has 28 protons.

Thus, an ion which has 26 protons, 28 neutrons, and 24 electrons  is Fe (option c)

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Answer:

The two hydrogen atoms and one oxygen atom within water molecules (H2O) form polar covalent bonds. ... As a result of water's polarity, each water molecule attracts other water molecules because of the opposite charges between them, forming hydrogen bonds.

Explanation:

Not my work, but I hope this helps!

Answer:

the rate is faster, and the time of reaction is 28 seconds

Explanation:

i did the test

Answer:

The rate is faster, 28 seconds

Explanation:

The Montreal Protocol, London Protocol, and Beijing Protocol are international agreements aimed at reducing stratospheric chlorine emissions and protecting the ozone layer. Among these protocols, the least aggressive in terms of decreasing stratospheric chlorine emissions is the Montreal Protocol.

The Montreal Protocol, adopted in 1987, is a global treaty that regulates the production and consumption of ozone-depleting substances (ODS). It has been successful in phasing out the production of major ODS such as chlorofluorocarbons (CFCs) and halons. By reducing the use of these substances, the Montreal Protocol has effectively decreased stratospheric chlorine emissions and helped in the recovery of the ozone layer.

The London Protocol, adopted in 1990, is an amendment to the original Montreal Protocol. It focuses on the elimination of chemicals known as ozone-depleting substances (ODS). Although it has contributed to the reduction of stratospheric chlorine emissions, the London Protocol is not as aggressive as the Montreal Protocol in terms of its targets and timelines for phase-out.

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The expression can be factored as (4h + 11)(4h + 11).

What exactly is an expression?

In chemistry, an expression is a basically statement or equation that describes the relationship between different chemical quantities. It usually involves mathematical operations and chemical symbols that represent elements and compounds. Expressions are used to describe chemical reactions, predict their outcomes, and develop new theories and models of chemical behavior.

This is because 4h + 11 can be written as (2h + 5)(2h + 5) and since 4h + 11 appears twice in the expression, we can factor it out of the entire expression.

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Answer:

3 valence electrons

Explanation:

Because aluminum has three, that means three fluorines can bond. The make the formula AlF3, also known as aluminum trifluoride. Each of the fluorine atoms gets an electron to fill their shell, and the aluminum loses three, giving it a filled shell too (remember, aluminum has three extra electrons).

Answer:

Can be absorbed and transformed into heat

Explanation:

You can fill in the table for other elements and their respective isotopes by determining the appropriate number of protons, neutrons, and electrons based on the given isotope mass number and atomic number.

To accurately fill in the table with the correct number of subatomic particles for the elements given the isotope mass number, we need to consider the composition of atoms and their respective subatomic particles. Atoms are composed of protons, neutrons, and electrons.

The number of protons in an atom is equivalent to its atomic number, which uniquely identifies the element. The number of neutrons can be determined by subtracting the atomic number from the isotope mass number. Electrons in a neutral atom are equal to the number of protons.

Let's take an example using the isotope mass number:

Isotope: Carbon-14 (mass number = 14)

Element: Carbon (atomic number = 6)Based on the atomic number and isotope mass number, we can determine the number of subatomic particles as follows:

Protons: 6 (same as the atomic number)

Neutrons: 14 - 6 = 8

Electrons: 6 (same as the number of protons in a neutral atom)

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The symptoms you are describing are commonly associated with an acute febrile illness, typically caused by an infection.

The patient may experience chills and rigors, followed by a fever spike that can reach up to 40C/104F. Sweating often follows the fever. It is important to seek medical attention if these symptoms persist or worsen. This type of fever is often caused by a bacterial or viral infection and is usually accompanied by other symptoms such as headache, fatigue, body aches and pains, and nausea. If left untreated, this type of fever can lead to more serious health complications. It is important to seek medical attention if any of these symptoms are present.

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Answer:

D or A your choice

Explanation:

uhhh didnt u- nvm

A neutralization reaction is when an acid and a base react to form water and a salt and involves the combination of H+ ions and OH- ions to generate wate

Teniendo en cuenta la ley de Boyle, el volumen del oxigeno a 415 mmHg, si la temperatura permanece constante, es 7,69 L.

Al aumentar el volumen, las partículas (átomos o moléculas) del gas tardan más en llegar a las paredes del recipiente y por lo tanto chocan menos veces por unidad de tiempo contra ellas. Esto significa que la presión será menor porque ésta representa la frecuencia de choques del gas contra las paredes.

De esta manera se relaciona la presión y el volumen, determinando la ley de Boyle que dice:

“El volumen ocupado por una determinada masa gaseosa a temperatura constante, es inversamente proporcional a la presión”

La ley de Boyle se expresa matemáticamente como:

P×V=k

Teniendo un estado inicial 1 y final 2, se cumple:

P₁×V₁= P₂×V₂

En este caso, se sabe que:

Reemplazando en la expresión matemática para la Ley de Boyle:

760 mmHg× 4.2 L= 415 mmHg× V₂

Resolviendo:

(760 mmHg× 4.2 L)÷ 415 mmHg= V₂

7,69 L= V₂

Finalmente, el volumen del oxigeno a 415 mmHg, si la temperatura permanece constante, es 7,69 L.

Aprende más:

The first thing we are going to analyze to solve the problem is our data, knowing what we have and what we need.

From what we can see, the problem asks us for the final volume, that is, P₂ , we are going to use the Boyle-Mariotte formula and start to isolate the variable we need to be able to start solving the problem. issue.

P₁V₁=P₂V₂

Clearing >> V₂

\(\boldsymbol{V_{2}=\dfrac{P_{1}V_{1} }{P_{2}} }\)

Substituting our data.

\(\boldsymbol{V_{2}=\dfrac{P_{1}V_{1} }{P_{2}}=\dfrac{(7600 \not{mmHg})(4.2 \ l)}{415\not{mmHg}}=\dfrac{3192}{415}l=7.69 \ l }\)

So our final volume is 7.69 liters.

With this we can conclude that while the pressure decreased the volume increased.

Answer: Measure the density

Explanation: pretty sure the density could identify if it is a mixture or a pure substance

To calculate the pH of the resulting solution after titrating 2.0 ml of 0.10 M NH3 with 25 ml of 0.10 M HCl, a detailed calculation is needed.

Given the volumes and concentrations of NH3 and HCl, we can determine the number of moles for each compound. The balanced chemical equation for the reaction between NH3 and HCl is NH3 + HCl → NH4Cl. By using the formula C * V = n (where C is concentration, V is volume, and n is moles), we find that NH3 has 0.0002 moles and HCl has 0.0025 moles. Since the reaction is 1:1, all NH3 is consumed, resulting in 0.0002 moles of NH4Cl. Considering the concentration of NH4Cl and its hydrolysis, the pH of the resulting solution is 9.25.

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To calculate the grams of NaCl in a 100 g solution with water, when the solution is 19% NaCl by weight, we can use the formula:

Grams of NaCl = Total weight of solution (in grams) × Percentage of NaCl / 100

In this case, the total weight of the solution is 100 g and the percentage of NaCl is 19%. Plugging in these values:

Grams of NaCl = 100 g × 19 / 100 = 19 grams

Therefore, there are 19 grams of NaCl in the 100 g solution.

Regarding the chemical reaction equation, to balance it, we can use the coefficients to adjust the number of atoms on each side.

The equation is: ___SO2 + ___O2 -> ___SO3

The correct balanced equation is: 2SO2 + O2 -> 2SO3

The coefficients in this balanced equation indicate that we need 2 molecules of SO2, 1 molecule of O2, and 2 molecules of SO3 to balance the reaction.

B. To calculate the density of a substance, we use the formula:

Density = Mass / Volume

In this case, the mass of the gasoline is given as 20.2 kg and the volume is given as 23.7 liters.

Density = 20.2 kg / 23.7 L

Calculating this:

Density = 0.851 Kg/L

Rounding this value to the correct significant figures gives:

Density = 0.85 Kg/L

Therefore, the density of gasoline is approximately 0.85 kg/L.

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Answer:

1.) can represent either the relative number of molecules, or the relative number of moles  

2.)MULTIPLY all the SUBSCRIPTS in the molecule by the COEFFICIENT.

i dont know the last one

Explanation:

Answer:

~2.054M

Explanation:

In this question ,I am going to assume that the acid is monoprotic acid(contains only one hydrogen) which I'll represent by HA.

Chemical equation:

NaOH(aq) + HA(aq)----->NaA(aq) + H2O(l)

The mole ratio of NaOH:HA is 1:1

1.25M NaOH=1.25 Moles/L or 1.25 moles /1000ml of NaOH

(1.25 moles /1000ml) x (24.65ml)=0.0308125 moles NaOH

Mole ratio is 1:1

So, moles of HA are also 0.0308125 moles

volume of HA  =15ml

To find molarity of HA:

=(0.0308125 moles x 1000ml)/(15ml)

~2.054M of HA

~Hope it helps:)

The pressure that the gas exerts at the higher temperature would be 20.83 atm.

According to Gay-Lussac's law, the pressure that a gas will exert on its container is directly proportional to the temperature of the gas, provided that the volume remains constant throughout.

This law can be mathematically expressed as:

\(p_1/t_1 = p_2/t_2\)

Where:

In this case, the initial temperature is given as 18 \(^oC\), the initial pressure is given as 2.5 atm, and the final temperature is given as 150 \(^oC\), We are to find the final pressure.

\(p_2\) = \(p_1t_2/t_1\)

   = 2.5x150/18

   = 20.83 atm

In other words, the new pressure that the gas will exert at a temperature of 150 \(^oC\) would be 20.83 atm.

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Answer:

N2 + 3H2 → 2NH3. 14 moles a. If 6 mol of H2 are consumed, how many moles of NH3 are produced? ... a 3 mol H₂. 4. How many moles of nitrogen are needed to make 11 moles of NH3? Il mol NH₃ x Imol Na = 15.5

Answer:

Since 1982, STP is defined as a temperature of 273.15 K (0 °C, 32 °F) and an absolute pressure of exactly 105 Pa (100 kPa, 1 bar).

Explanation:

I hope I helped