The valence electrons of a krypton (Kr) atom in the ground state are located in the


A. first energy level (shell).

B. second energy level (shell).

C. third energy level (shell).

D. fourth energy level (shell).

When an electron moves from n = 2 to n = 1, it emits a photon of ultraviolet light.

During transition from n=2 to n=1 in a hydrogen atom, the electron emits energy in the form of photon. We know that when electron absorb energy, it moves from lower level to higher level and vice versa.

So we can conclude that when an electron moves from n = 2 to n = 1, it emits a photon of ultraviolet light.

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Answer: the evaporation of the solute increases the vapor pressure. The increased vapor pressure prevents the solute from elevating the boiling point or depressing the freezing point of the solvent.

Explanation:

According to forces of attraction, colligative properties are different when volatile solute is used as evaporation of  solute increases  vapor pressure.  Increased vapor pressure prevents  solute from elevating  boiling point or depressing  freezing point of the solvent.

Forces of attraction  is a force by which atoms in a molecule  combine. it is basically an attractive force in nature.  It can act between an ion  and an atom as well.It varies for different  states  of matter that is solids, liquids and gases.

The forces of attraction are maximum in solids as  the molecules present in solid are tightly held while it is minimum in gases  as the molecules are far apart . The forces of attraction in liquids is intermediate of solids and gases.

The physical properties such as melting point, boiling point, density  are all dependent on forces of attraction which exists in the substances.

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Answer:

Uiiikjhb+2

Explanation:

I’m gonna swinggggggf

Answer:I believe you mean Mg(HCO3)2. Since I have never heard of the element MA. but if you are calculating using mg(HCO3)2 your molar mass/ molecular mass will be  146.3387

Explanation:

An example of heterogeneous equilibrium is:

Heterogeneous equilibrium refers to an equilibrium state in a chemical reaction where the reactants and products exist in different physical states or phases. It occurs when substances in different phases, such as solids, liquids, and gases, are involved in a chemical reaction.

Considering the given equations:

The equation I: FeO(s) + CO(g) ⇌ Fe(s) + CO₂(g) represents a heterogeneous equilibrium.

This is because the reactants and products involve different phases (solid and gas). FeO is a solid (s), CO is a gas (g), Fe is a solid (s), and CO₂ is a gas (g). The reaction involves the conversion of a solid and a gas to another solid and a gas, and the equilibrium is established between these different phases.

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Answer:

A. just took the test!!!

Explanation:

According to the forces of attraction, the  situation best models the formation amorphous solid because the particles do not have a regular structure.

Forces of attraction  is a force by which atoms in a molecule  combine. it is basically an attractive force in nature.  It can act between an ion  and an atom as well.It varies for different  states  of matter that is solids, liquids and gases.

The forces of attraction are maximum in solids as  the molecules present in solid are tightly held while it is minimum in gases as the molecules are far apart . The forces of attraction in liquids is intermediate of solids and gases.

The physical properties such as melting point, boiling point, density  are all dependent on forces of attraction which exists in the substances.

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Answer:

A.S1 only

Explanation:

A compound is one of the pure substances (other being element) that forms when two or more atoms of an element are chemically combined. According to this question, a solid S1 is heated and it breaks up into gas G and another solid S2 as follows:

S1 (s) ➡ G (g) + S2 (s)

Based on the information in the questio, the solids S1, S2 and the gas G are all pure substances. However, since solid S1 broke down into two other pure substances, it means solid S1 is originally a chemical combination of both products, which denotes a COMPOUND. Note that Gas G and Solid S2 are most likely elements.

The physical property that is characteristic of all of the elements in the group located in the rightmost column of the periodic table is the gaseous state at room temperature.

Physical properties may be defined as those properties of matter that do not involves any chemical manifestation or appearance within the element. These properties are measurable and state the alteration between momentary states. Some examples of physical properties are as follows:

The groups located in the rightmost column of the periodic table are known as the halogens and the noble gases. These elements are typically gaseous in phase at room temperature. Apart from this, halogens also have high electronegativities because these elements have seven electrons in their valence electrons.

Therefore, the gaseous state at room temperature is the physical property that is characteristic of all of the elements in the group located in the rightmost column of the periodic table.

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Answer:

C

Explanation:

sorry if im wrong!!

Answer:

c.CH4 < NH3 because the NH bond is more polar than the CH bond.

Explanation:

Answer:

177.3 meters per second

Explanation:

Assuming that both gases are at the same temperature, we can use Graham's law to calculate the ratio of the average speeds of N2 and He molecules:

(ratio of speeds) = sqrt(molar mass of He/molar mass of N2)

The molar mass of N2 is 28.02 g/mol, and the molar mass of He is 4.00 g/mol. Therefore:

(ratio of speeds) = sqrt(4.00/28.02) = 0.379

We know that the average speed of N2 molecules is 468 m/s. Therefore:

(average speed of He molecules) = (ratio of speeds) x (average speed of N2 molecules) = 0.379 x 468 m/s = 177.3 m/s

Therefore, the average speed of He molecules at the same temperature is approximately 177.3 meters per second.

Answer: answer what..

Answer:

evan..

Explanation:

Answer:

First, we need to convert 0.750 g of lidocaine into milligrams (mg):

0.750 g = 750 mg

Next, we can calculate the total volume of the solution needed to administer 750 mg of lidocaine. Since each 150 mL of the solution contains 500 mg of lidocaine, we can set up the following proportion:

(750 mg) / (500 mg) = (x mL) / (150 mL)

Cross-multiplying:

500x = 750 * 150

500x = 112,500

x = 112,500 / 500

x = 225 mL

Now, we know that it will take 225 mL of the solution to administer 750 mg of lidocaine.

To find the time it takes to infuse 225 mL at a rate of 300 mL/hr, we can set up another proportion:

(225 mL) / (300 mL/hr) = (y min) / (60 min)

Cross-multiplying:

300y = 225 * 60

300y = 13,500

y = 13,500 / 300

y = 45 min

Therefore, it will take 45 minutes to administer 0.750 g (or 750 mg) of lidocaine at a rate of infusion of 300 mL/hr.

It will take approximately 75 minutes for 0.750 g of lidocaine to be administered through the IV at a rate of 300 mL/hr.

To calculate the time it takes to administer 0.750 g of lidocaine, we need to use the information provided.

Given:

Each 150 mL of the solution contains 500 mg of lidocaine.

The rate of infusion is set at 300 mL/hr.

First, we need to determine the amount of lidocaine administered per mL of the solution:

500 mg of lidocaine per 150 mL of solution = 500 mg / 150 mL ≈ 3.33 mg/mL

Next, we can convert the amount of lidocaine to be administered (0.750 g) to milligrams:

0.750 g * 1000 mg/g = 750 mg

Now, we can calculate the total volume of the solution needed to administer 750 mg of lidocaine:

750 mg / 3.33 mg/mL ≈ 225.23 mL

Finally, we can find the time it takes to administer 225.23 mL of the solution at a rate of 300 mL/hr.:

Time (in hours) = Volume (mL) / Rate (mL/hr.)

Time (in hours) = 225.23 mL / 300 mL/hr ≈ 0.75077 hr.

Converting hours to minutes:

Time (in minutes) ≈ 0.75077 hr * 60 min/hr ≈ 45.05 min

Therefore, it will take approximately 75 minutes for 0.750 g of lidocaine to be administered.

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Answer:

option a

Explanation:

The group number of an element is equal to the number of electrons the outermost shell (or highest energy level) contains

The lowest energy level of sodium contains electrons.

An electron is defined as a subatomic particle which is charged negatively either bound to an atom or not it means free. The nucleus of an atom is made up of electron, proton and neutron.The main function of electron is that they play the role of negatively- charged component of an atom. The electron is a basic particle and electron is not made of anything.

The nature of electron is free it means they are present freely in nature and consist of an atom.The main function of electron is that they play the role of negatively- charged component of an atom.

The electrons are primary source of current conducting and electrons number as well as atomic number of an element is always same or equal. There is no size of electron but the mass of electron is 9×10^-31.

Therefore,The lowest energy level of sodium contains electrons.

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Mg 2+(aq) + 2NO2 -(aq)  ⇒ Mg(NO2)2 (aq)

What is enthalpy?

In a thermodynamic system, energy is measured by enthalpy. Enthalpy is a measure of a system's overall heat content and is equal to the system's internal energy plus the sum of its volume and pressure.

The amount of heat released or absorbed during a reaction that takes place under constant pressure is referred to as the enthalpy change. The sign for it is H, which can be read as "delta H." If the system's enthalpy drops relative to the reaction, the reaction is preferred. A balanced chemical equation is followed by and on the same line as the enthalpy change for the reaction.

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answer:

high temperatures

hydrogen gas

Answer:

C and D

Explanation:

just did this on edg :)

Answer:

\(15molH\)

Explanation:

Hello,

In this case, given that one mole of glucose, contains six moles of oxygen (subscript), we can also see it contains twelve moles of hydrogen (subscript), therefore, the moles of hydrogen in the sample are computed by:

\(0.75molO*\frac{1molC_6H_{12}O_6}{6molO}*\frac{12molH}{1molC_6H_{12}O_6}\\ \\=1.5molH\)

Best regards.

The volume of O₂ produced when 8.52 g of Na₂O₂ is added to excess water is approximately 1.17 liters at STP.

When it comes to the ideal gas law, the underlying assumption is that the gas is in a state of thermodynamic equilibrium. This means that its molecules are not interacting with each other except through perfectly elastic collisions.

Equation:

We can use stoichiometry to determine the volume of oxygen gas produced from the reaction of 8.52 g of Na₂O₂.

First, we need to convert the mass of Na₂O₂ to moles using its molar mass:

8.52 g Na₂O₂ × (1 mol Na₂O₂ / 77.98 g Na₂O₂) = 0.1093 mol Na₂O₂

According to the balanced chemical equation, 1 mole of Na₂O₂ produces 1/2 mole of O₂:

2 Na₂O₂ + 2 H₂O → 4 NaOH + O₂

1 mol Na₂O₂ produces 1/2 mol O₂

So, the number of moles of O₂ produced is:

0.1093 mol Na₂O₂ × (1/2 mol O₂ / 1 mol Na₂O₂) = 0.05465 mol O₂

Finally, we can use the ideal gas law to determine the volume of O₂ produced at standard temperature and pressure (STP), which is defined as 0°C (273 K) and 1 atmosphere (1 atm) of pressure:

PV = nRT

At STP, the pressure and temperature are known, so we can rearrange the equation to solve for V:

V = nRT / P

Plugging the values, we get:

V = (0.05465 mol) × (0.08206 L atm mol⁻¹ K⁻¹) × (273 K) / (1 atm)

V ≈ 1.17 L

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Answer:

C

Explanation:

I hope this is correct and have a great day

The ionization of the following acids can be represented as:

Tetraoxosulphate (VI) Acid (\(H_{2}SO_{4}\)) ionizes as H+ and SO4^2- ions.

Trioxonitrate (V) Acid (\(HNO_{3}\)) ionizes as H+ and \(NO_{3-}\) ions.

Ethanoic Acid (\(CH_{3}COOH\)) ionizes as H+ and \(CH_{3}COO^{-}\) ions.

Tetraoxosulphate (VI) Acid, also known as sulfuric acid (\(H_{2}SO_{4}\)), ionizes as follows:

\(H_{2}SO_{4}\) → \(H+\) + \(SO_{4}^{2-}\)

In this reaction, sulfuric acid donates two hydrogen ions (H+) to the solution, forming sulfate ions (\(SO_{4}^{2-}\)).

Trioxonitrate (V) Acid, commonly known as nitric acid (\(HNO_{3}\)), ionizes as follows:

\(HNO_{3}\) → \(H+_{}\) + \(NO_{3-}\)

Nitric acid dissociates to release one hydrogen ion (\(H+\)) and a nitrate ion  (\(NO_{3-}\)).

Ethanoic Acid, also known as acetic acid (\(CH_{3}COOH\)), ionizes as follows:

\(CH_{3}COOH\) → H+ + \(CH_{3}COO^{-}\)

Acetic acid donates a hydrogen ion (H+) to the solution, forming an acetate ion (\(CH_{3}COO^{-}\)).

In all cases, the acids dissociate in water, producing hydrogen ions (H+) as positively charged ions and their corresponding anions. The hydrogen ions are responsible for the acidic properties of these substances, while the anions contribute to the overall charge balance in the solution. The ionization of acids allows them to conduct electricity in aqueous solutions and react with other substances.

The question was incomplete. find the full content below:

Indicate the ionization of the following acids,

Tetraoxosulphate (VI) Acid

Trioxonitrate (V) Acid

Ethanoic Acid.​

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Mechanical disintegration means breaking into small pieces (option A).

Digestion is the process occuring in the gastrointestinal tract, by which food is converted into substances that can be utilized by the body.

Digestion can, however, be mechanical/physical or chemical/enzymatical. The mechanical digestion involves the breaking down of food into smaller pieces by teeth.

Therefore, according to this question, there is no passage, however, the meaning of mechanical disintegration can be easily detected in biology.

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There are 0.161 moles of copper atoms in a 25.7 g sample of CuSO4.

To determine the number of moles of copper atoms in a sample of CuSO4, we first need to know the molar mass of CuSO4.

The molar mass of CuSO4 can be calculated by adding the atomic masses of copper, sulfur, and four oxygen atoms:

1 x Cu = 63.55 g/mol

1 x S = 32.06 g/mol

4 x O = 15.99 g/mol x 4 = 63.96 g/mol

Molar mass of CuSO4 = 63.55 g/mol + 32.06 g/mol + 63.96 g/mol = 159.57 g/mol

Now that we know the molar mass of CuSO4, we can use it to calculate the number of moles of copper atoms in a 25.7 g sample:

moles of Cu atoms = mass of CuSO4 / molar mass of CuSO4

moles of Cu atoms = 25.7 g / 159.57 g/mol

moles of Cu atoms = 0.161 moles

Therefore, there are 0.161 moles of copper atoms in a 25.7 g sample of CuSO4.

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Answer:

Normal boiling point is a standard boiling point at sea level highet that is 100 c°

but the temperature at which water boils may vary with different factors like increasing pressure in pressure cooker.

And it decreases with increase in height.

Explanation:

The boiling point of a liquid is the temperature at which its vapor pressure is equal to the pressure of the gas above it. The normal boiling point of a liquid is the temperature at which its vapor pressure is equal to one atmosphere (760 torr).

Normal boiling point is a standard unit  and the highest is 100 c°  at sea level but the temperature at which water boils and the temperature may vary with respect to different factors.  

The boiling point is defined as the temperature at which the liquid vapor pressure is equal to the external pressure surrounding the liquid.

The boiling point of a liquid depend on atmospheric pressure.

When external pressure is reduced, the boiling point will be lowered. For example at sea level the boiling point of water is 100 C  but when we go to 6,600 feet the boiling point become 93.4 C

The standard boiling point is defines  as the temperature of boiling under 1 bar of pressure.

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Explanation:

Sodium and oxygen react to produce sodium oxide. The balanced equation of the reaction is:

4 Na + O₂ ----> 2 Na₂O

First we can convert the 45.35 g of Na₂O into moles using its molar mass.

molar mass of Na = 22.99 g/mol

molar mass of O = 16.00 g/mol

molar mass of Na₂O = 2 * 22.99 g/mol + 1 * 16.00 g/mol

molar mass of Na₂O = 61.98 g/mol

moles of Na₂O = 45.35 g * 1 mol/(61.98 g)

moles of Na₂O = 0.7317 moles

4 Na + O₂ ----> 2 Na₂O

According to the coefficients of the reaction, 4 moles of Na will react with 1 mol of O₂ to produce 2 moles of Na₂O. Then the molar ratio between O₂ and Na₂O is 1 to 2. We can use that relationship to find the answer to our problem.

1 mol of O₂ : 2 moles of Na₂O

moles of O₂ = 0.7317 moles of Na₂O * 1 mol of O₂/(2 moles of Na₂O)

moles of O₂ = 0.3659 mol

Answer: 0.3659 moles of oxygen are needed to produce 45.35 g of sodium oxide.

Answer:

The pulling atom is oxidized while the pulled atom is reduced. Grade 9 Chemistry

Explanation:

Answer:

\(T_{eq}=28.9\°C\)

Explanation:

Hello!

In this case, since it is observed that hot cadmium is placed in cold water, we can infer that the heat released due to the cooling of cadmium is gained by the water and therefore we can write:

\(Q_{Cd}+Q_{W}=0\)

Thus, we insert mass, specific heat and temperatures to obtain:

\(m_{Cd}C_{Cd}(T_{eq}-T_{Cd})+m_{W}C_{W}(T_{eq}-T_{W})=0\)

In such a way, since the specific heat of cadmium and water are respectively 0.232 and 4.184 J/(g °C), we can solve for the equilibrium temperature (the final one) as shown below:

\(T_{eq}=\frac{m_{Cd}C_{Cd}T_{Cd}+m_{W}C_{W}T_{W}}{m_{Cd}C_{Cd}+m_{W}C_{W}}\)

Now, we plug in to obtain:

\(T_{eq}=\frac{37.60g*0.232\frac{J}{g\°C}*100.00\°C+25.00g*4.184\frac{J}{g\°C}*23.0\°C}{37.60g*0.232\frac{J}{g\°C}+25.00g*4.184\frac{J}{g\°C}}\\\\T_{eq}=28.9\°C\)

NOTE: since the density of water is 1g/cc, we infer that 25.00 cc equals 25.00 g.

Best regards!

Answer: B, 57.1%

Explanation: 400 divided by 700 = .571 (roughly), which is 57.1%

Answer:

x/2

Explanation:

X = 2 molecules of H2

For 2 molecules of H2, there's only 1 molecule of O2. Meaning, there's twice the amount of H2, so O2 = x/2 molecules.

I hope I'm understanding this question right.

Answer:

Molarity = 1.28

Explanation:

\(m= n/v\)

M = molar concentration

n = moles of solute

v = liters of solution

Molarity = moles of solute / litres of solution.

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