how can you tell how many valence electrons an element has

The anion radius is 0.072 nm.  the cation has a charge of +2, the anion must have a charge of -2

The force of attraction between a divalent cation and an anion is proportional to the product of their charges and inversely proportional to the distance between them. The force can be expressed as F = k * q1 * q2 / r, where k is the Coulomb constant (8.99 x\(10^-9\) N \(m^2/C^2\)), q1 and q2 are the charges of the cation and anion, respectively, and r is the distance between the centers of the ions.

Since the cation has a charge of +2, the anion must have a charge of -2. Rearranging the equation and plugging in the known values, we can solve for the anion radius: r = sqrt(k * q1 * q2 / F) = sqrt(8.99 x \(10^9\) N \(m^2/C^2\) * 2 * 2 / (1.92 x \(10^-8\) N)) = 0.072 nm.

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Answer:

The correct answer is 1.66 atm ≅ 1.7 atm

Explanation:

Given:

T₁ = -13°C + 273 = 260 K (initial temperature)

T₂ = 15°C + 273 = 288 K (final temperature)

P₁ = 1.5 atm

P₂= ?

We use the mathematical expression of Gay Lussac's Law to calculate P₂, as follows:

P₁/T₁ = P₂/T₂

P₂= P₁/T₁ x T₂ = (1.5 atm)/(260 K) x 288 K = 1.66 atm ≅ 1.7 atm

Since the law says that the temperature of a gas is directly proportional to the pressure, when the temperature is increased, the pressure increases.

To determine the number of grams of sulfur dioxide formed when 10.0 mol of copper(I) sulfide reacts during the process of roasting, we need to use the balanced chemical equation and the molar masses of the compounds involved.

The balanced chemical equation for the reaction of copper(I) sulfide (Cu2S) with oxygen (O2) to form copper(I) oxide (Cu2O) and sulfur dioxide (SO2) is:

2 Cu2S + 3 O2 → 2 Cu2O + 2 SO2

From the balanced equation, we can see that for every 2 moles of Cu2S, 2 moles of SO2 are formed.

Therefore, using the stoichiometry of the reaction:

10.0 mol Cu2S * (2 mol SO2 / 2 mol Cu2S) = 10.0 mol SO2

Next, we can calculate the mass of sulfur dioxide using the molar mass of SO2, which is approximately 64.06 g/mol:

Mass of SO2 = 10.0 mol SO2 * 64.06 g/mol

= 640.6 g

Therefore, when 10.0 mol of copper(I) sulfide reacts during roasting, approximately 640.6 grams of sulfur dioxide are formed.

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Answer:

A. 1.73 m = 172 cm

B. 7,651.27 m = 7.65127 Km

Antibiotics are effective on bacterial cells. This means they would not work on which two infections from question 1? Common cold and influenza ("flu").

Antibiotics are a type of medication that will fight bacterial infections by killing the bacteria and preventing their growth. It will then affect living microorganisms.

It will then not be effective in viral infections since viruses are not living beings, which will not do anything to them and what will generate is that in the individual who is taking the antibiotics, the bacteria generate antibiotic resistance making it more difficult to eradicate them when it is generated by a bacterial infection.

Therefore, we can confirm that in a common cold and influenza the use of antibiotics is not going to be effective because they are caused by viral agents that will not be eradicated.

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As the reaction between the two gases proceeds, the volume of the container will decrease due to the formation of a new gas, XY, which takes up less space than the two gases combined.

In a closed system, the decrease in volume is accompanied by an increase in pressure, as the molecules of XY have less space to move around in than the molecules of X and Y.

This is because the increased pressure will cause the molecules to move faster, thereby increasing the kinetic energy of the system. This increase in temperature will cause the reaction to speed up, leading to more molecules of XY being formed. As the reaction continues, the pressure, temperature, and volume will continue to change in a dynamic equilibrium until all the reactants are used up.

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Answer:

B

The chemical formula does not show how the atoms are connected to one another

Answer:

b

Explanation:

edge 2020

Based on the electrophoresis sample, it appears that DNA samples B and E are the most similar. Electrophoresis separates DNA fragments based on size and charge.

These similarities could mean that the DNA in these samples may have similar sequences or may come from related individuals or species. Regarding the presence of the baldness gene, it is not possible to determine from the electrophoresis which other DNA samples may also have the baldness gene. This is because the electrophoresis technique only separates DNA fragments based on size, and it cannot determine the sequence or identity of the DNA fragments.

Therefore, to determine which other DNA samples may have the baldness gene, additional genetic testing would be required, such as PCR or DNA sequencing, to detect the presence of the specific mutation associated with baldness. Overall, electrophoresis is a powerful technique used in molecular biology to separate and analyze DNA fragments. While the technique has its limitations, such as the inability to determine the identity of the separated fragments, it is still widely used to study DNA and other biomolecules.

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Answer:

1 billion

Explanation:

The computation of the number of atoms for C-14 is shown below:

Because it is mentioned

Half the isotope for carbon 14 is 5,730 years

Currently if there had been 4 billion it would equate to 2 billion

Now that the 2 billion would've been 1 billion in the next 5,730 years

And it'll become 3 half-life

Therefore the number of C-14 atoms is 1 billion

The final pressure of carbon dioxide in the soda bottle, assuming it had the full 2.00 L in which to expand, is 1.20 atm.

The equation for the decomposition of carbonic acid is: H2CO3 → H2O + CO2.

When 75.0 g of carbonic acid is sealed in a 2.00 L soda bottle at room temperature (298.15 K), the decomposition reaction will occur and the carbon dioxide (CO2) will expand to fill the available space in the bottle.

The final pressure of carbon dioxide (in atm), the ideal gas law equation:

PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the universal gas constant, and T is the temperature.

Since we know the initial amount of carbonic acid (75.0 g), the number of moles present: n = (75.0 g H2CO3) / (84.01 g/mol), giving us a value of 0.894 moles.

The volume of the bottle (2.00 L) and the temperature (298.15 K). Thus, we can plug these values into the ideal gas law equation to calculate the final pressure of carbon dioxide:

P = (0.894 mol CO2) (0.08206 L*atm/K*mol) (298.15 K) / (2.00 L), which gives us a pressure of 1.20 atm.

Therefore, the final pressure of carbon dioxide in the soda bottle, assuming it had the full 2.00 L in which to expand, is 1.20 atm.

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Answer:

Gas Pressure

Explanation:

Gas pressure is caused by the force exerted by gas molecules colliding with the surfaces of objects (Figure 5.2. 1). Although the force of each collision is very small, any surface of appreciable area experiences a large number of collisions in a short time, which can result in a high pressure.

Answer:

Collisions

Explanation:

It says that it was the answer.

The following descriptions and/or equations best represent the enthalpy change of a system: C. The heat absorbed or released during a phase change or chemical reaction at constant pressure; E. ΔH = ΔE + PΔV; F. H = E + PV.

Enthalpy (H) is a thermodynamic property that represents the total heat content of a system. It takes into account both the internal energy (E) of the system and the work done by or on the system in the form of pressure-volume work (PV).

Option C states that enthalpy change occurs during a phase change or chemical reaction at constant pressure. This is because at constant pressure, the heat absorbed or released by the system is equal to the change in enthalpy.

Option E, ΔH = ΔE + PΔV, represents the equation for calculating the change in enthalpy, where ΔE is the change in internal energy and PΔV is the pressure-volume work done.

Option F, H = E + PV, directly defines enthalpy (H) as the sum of internal energy (E) and pressure-volume work (PV).

These options highlight the relationship between enthalpy, internal energy, and work in the context of phase changes, chemical reactions, and constant pressure conditions.

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One question that can be solved by scientific investigation is:

To answer this question, you would need data on CO₂ levels from different areas around the town including measurements taken over a period of time. It will be important to consider the intake of the surrounding plantations or green spaces to assess the overall carbon balance.

So, by analyzing these data, we can evaluate the impact of the town's efforts on climate change most specifically in terms of CO₂ levels and the oxygen to CO₂ ratio.

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Therefore, the pH and the equilibrium concentration of S²⁻ in a 6.89x10⁻² M hydrosulfuric acid solution are pH = 7.78 and [S²⁻] = 2.31x10⁻¹¹ M.

Hydrosulfuric acid (H₂S) is a weak acid that dissociates in water to produce hydrogen ions (H⁺) and bisulfide ions (HS⁻). H₂S(aq) + H₂O(l) ⇌ H₃O⁺(aq) + HS⁻(aq)

The bisulfide ions (HS⁻) in turn reacts with water to produce hydronium ions (H₃O⁺) and sulfide ions (S²⁻).

HS⁻(aq) + H₂O(l) ⇌ H₃O⁺(aq) + S²⁻(aq) Ka1

= 1.0x10⁻⁷,

Ka2 = 1.0x10⁻¹⁹

To calculate the pH and the equilibrium concentration of S²⁻ in a 6.89x10⁻² M H₂S(aq) solution, we must first determine if H₂S(aq) is a strong or weak acid.

It has Ka1 = 1.0x10⁻⁷, which is a very small value; thus, we can conclude that H₂S(aq) is a weak acid.

To calculate the equilibrium concentration of S²⁻ in a 6.89x10⁻² M H₂S(aq) solution, we need to use the Ka2 value (Ka2 = 1.0x10⁻¹⁹) and a chemical equilibrium table.

[H₂S] = 6.89x10⁻² M[H₃O⁺] [HS⁻] [S²⁻]

Initial 0 0 0Change -x +x +x

Equilibrium (6.89x10⁻² - x) x xKa2 = [H₃O⁺][S²⁻]/[HS⁻]1.0x10⁻¹⁹

= x² / (6.89x10⁻² - x)

Simplifying: 1.0x10⁻¹⁹ = x² / (6.89x10⁻²)

Thus: x = √[(1.0x10⁻¹⁹)(6.89x10⁻²)]

x = 2.31x10⁻¹¹ M

Thus, [S²⁻] = 2.31x10⁻¹¹ M

To calculate the pH of the solution, we can use the Ka1 value and the following chemical equilibrium table.

[H₂S] = 6.89x10⁻² M[H₃O⁺] [HS⁻] [S²⁻]

Initial 0 0 0

Change -x +x +x

Equilibrium (6.89x10⁻² - x) x x

Ka1 = [H₃O⁺][HS⁻]/[H₂S]1.0x10⁻⁷

= x(6.89x10⁻² - x) / (6.89x10⁻²)

Simplifying: 1.0x10⁻⁷ = x(6.89x10⁻² - x) / (6.89x10⁻²)

Thus: x = 1.66x10⁻⁸ M[H₃O⁺]

= 1.66x10⁻⁸ M

Then, pH = -log[H₃O⁺]

= -log(1.66x10⁻⁸)

= 7.78 (rounded to two decimal places)

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Answer:

Iodine

Explanation:

Iodine is in group 17 on the periodic table (first picture attached). The second picture shows you in the top left-hand corner of Iodine's little square, there is the number 53. This is the atomic number, it is also the number of protons and electrons in an element.

Hope this helped :)

Answer:

Modification Step

Explanation:

The entire reason why test-marketing exists is to make sure that the product will be well received by the public. Once the test marketing concludes, the data from the test is analyzed. Then the company decides whether or not they will make changes on how the product looks, feels, performs, or even rebranding the product, all to make sure that the final consumer will like the product enough to want to purchase and continuously use the product. Which will in term increase profits for the company.

The new rate of the modified reaction will be 44mmmM/s which can be calculated by the rate of disappearance.

For this response, the rate of disappearance was calculated. The concentration will drop as it is consumed. After 54 minutes, the concentration dropped to 1.58 molar.

What is the reaction's speed?

Units are a way to express the reaction rate. HCl is characterized by a change in polarity of the compound per unit of time or per change in time. We have 1.85 Molar moving to 1.58 Molar in 54 minutes. Ten times as much negative three molar HCl would be produced each minute. People should subtract the initial polarity from the end one to do it correctly.

Because of the drug's concentration, we experience a negative rate of reaction. The fact that the rate is negative indicates that we are consuming.

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Answer:

Here is every answer for analog and digital (in order)

Analog:

Digital (in order):

Explanation:

I did mine in bullet points, hopefully this helped!

Analog:

Signal Shape: Smooth and continuous

Numerical Values for Signal Estimations: Analog signals speak to one ceaseless variable as the result of another ceaseless time-based variable.

Amount of Information that can be transmitted: analog circuits can conduct as it were reasonably low-speed information communications.

Energy necessities: light, sound, temperature, position, and pressure Privacy and security : not encrypted

Clarity of Signal: clamor influences clarity and quality, commotion is amplified,

Digital:

Signal shape: stepping, square, and discrete

Numerical Values for Signal Measurements: digital communication methods transmit a complete measured value, in other words both a numeric value and a unit of measurement

Amount of data that can be transmitted: First of all, it is theoretically possible to transmit digital signals directly.

Energy requirements: voltage, accoustic pressure.

Privacy and security: encrypted

Clarity of signal: noise is lower in amplitude, electronics can ignore the noise, quality of signal is maintained, signal is high

Analog signal could be a continuous signal which speaks to physical estimations.

Digital signals are discrete time signals created by computerized balance.

Example :Human voice in discuss, analog electronic gadgets. Computers, CDs, DVDs, and other advanced electronic gadgets.

The percent purity of your experimental sample is 97.3 %

The percentage purity % = impure value/pure value × 100 %.

Actual value of molar extinction coefficient = impure value = 8171 L/mol-cm, pure value = literature value = 8400 L/mol-cm.

Substituting the values of the variables into the equation, we have

% purity = 8171 L/mol-cm/8400 L/mol-cm ×  100 %

% purity = 0.9727 × 100 %

% purity =  97.27 %

% purity ≅  97.3 %

The percent purity of your experimental sample is 97.3 %

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Answer:

True.

Explanation:

To describe the problem of trying to locate a subatomic particle that behaves  like a wave, Werner Heisenberg formulated what is now known as the Heisenberg  uncertainty principle: it is impossible to know simultaneously both the momentum p  (defined as mass times velocity) and the position of a particle with certainty.

Making measurement of the momentum of a particle more precise means that the position must become correspondingly less  precise. Similarly, if the position of the particle is known  more precisely, its momentum measurement must become less precise.

a sponge because it lets in some of the dirt and mess but it doesn't let in all of it as in a shovel doesn't really take in anything

A sponge has selective permeability, while a shovel does not. Selective permeability refers to the ability of a material or membrane to allow certain substances to pass through while restricting the passage of others.

In the case of a sponge, it has a porous structure with small openings that can absorb and hold liquids, while allowing water to pass through. This selective permeability enables a sponge to soak up and retain liquids while filtering out larger particles.

A shovel is typically made of solid materials like metal or plastic, which do not possess selective permeability. A shovel's main purpose is to scoop and transport materials such as soil, sand, or snow, but it does not have the ability to selectively allow substances to pass through its structure.

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336.69 g ≈337 g

337 g is the theoretical yield.

2 Cs + Cl2 ---> 2 CsCl

Two moles gives two moles

Convert moles into mass:

molar mass of cs = 132.91 g/mol

molar mass of cl = 35.453 g/mol

molar mass of 2CsCl

= 2 * 168.36

= 336.72

Now,

2 Cs + Cl2           --->     2 CsCl

cl2 =70.906                  2 * 168.36

70.906                         336.72

If 70.906g of chlorine produces 336.72 g of 2CsCl,

70.9 g of chlorine produces how much 2CsCl?

70.906 g of Cl ≅ 336.72 g of 2CsCl

70.9 g of Cl ≅ X of 2CsCl

∴X = 70.9 × 336.72 / 70.906

X = 336.69 g

The theoretical yield of 2CsCl = 336.69 g

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Answer:

rest will do later mom is calling me plz understand promise will do it

Explanation:

Answer:

lol

Explanation:

its 5 points

Answer:

13.7 liters

Explanation:

I took the test and got it right

The total volume of the NaCl solution whose molarity is 0.04 M is 13.7 liters.

Molarity of any solution is define as the number of moles of solute present in per liter of the solution and it will be represented as:

M = n/V

Mass from moles will be calculated as:
n = W/M, where

W = given mass of NaCl = 32g

M = molar mass of NaCl = 58.44g/mol

mole = 32g / 58.44g/mol = 0.547 mol

Molarity of solution = 0.04 M

On putting values on the above equation, we get volume as:
V = 0.547 mol / 0.04mol/L

V = 13.67 L = 13.7L

Hence required value of volume is 13.7 L.

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The daughter cannot be claimed because she fails the gross income test

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Answer:

The answer is D

Explanation:

Dont think you need one

Answer:

The correct option is B The energy needed to change the temperature of a substance.

Explanation:

Specific heat capacity is the amount of energy required to raise the temperature of one unit mass of a substance by one degree Celsius or Kelvin. This means that it is the energy needed to change the temperature of a substance, which is option B.

Some key points about specific heat capacity include:

- It is a property of a substance and can vary depending on the material.

- It is typically measured in units of J/(g·°C) or J/(kg·K).

- The specific heat capacity of water is relatively high, meaning that it requires a lot of energy to heat up or cool down compared to other substances.

- Specific heat capacity is often used in calculations involving thermal energy transfer, such as calculating the amount of heat needed to heat up a substance.

Examples of how specific heat capacity is used include calculating the energy needed to heat up a pot of water on the stove or determining the amount of heat released by a reaction based on the specific heat capacity of the products and reactants.

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(a) The balanced chemical equation for the reaction can be given as:

CO (g) + H2O (g) → CO2 (g) + H2 (g)

(b) The internal energy change (∆U) for the given reaction of 1.40 g of carbon monoxide with excess water vapor to produce carbon dioxide and hydrogen gases in a bomb calorimeter is 0 J.

(a) The balanced equation for the given reaction of 1.40 g of carbon monoxide with excess water vapor to produce carbon dioxide and hydrogen gases in a bomb calorimeter is given below.

Carbon monoxide (CO) reacts with water (H2O) to produce carbon dioxide (CO2) and hydrogen (H2) gas.

CO (g) + H2O (g) → CO2 (g) + H2 (g)

(b) To calculate the internal energy change (∆U) for the given reaction of 1.40 g of carbon monoxide with excess water vapor to produce carbon dioxide and hydrogen gases in a bomb calorimeter, we can use the following equation:

∆U = -q

where q is the heat energy absorbed by the calorimeter.

The heat absorbed by the calorimeter (q) can be calculated using the following formula:

q = C∆T

where C is the total heat capacity (calorimeter constant) of the calorimeter assembly and ∆T is the change in temperature observed in the calorimeter assembly during the reaction.

The value of C is given as 150 J/°C. The initial temperature of the calorimeter assembly is not provided. So we assume the initial temperature to be same as the final temperature in the calorimeter assembly (30.2°C).

Hence, ∆T = 30.2 - 30.2 = 0°C.

The heat absorbed by the calorimeter (q) is thus given as:

q = C∆T= 150 J/°C × 0°C= 0 J

Substituting the value of q in the equation for ∆U, we get:

∆U = -q= -0 J= 0 J

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