What protects the earth from the sun's rays​

An example of disruptive selection because both extremes are favored to survive is a Selection for the homozygous dominant (AA).

The CCRS-delta 32 gene provided immunity to a deadly disease of bacterial origin, bubonic plague. People who are homozygous for the CCR5-della 32 gene variant are completely immune, while heterozygotes only have partial immunity and homozygous recessive have none is a Selection against the heterozygote and one homozygote.

Sickle cell disease - homozygous dominant contract malaria, homozygous recessive die young from sickle cell, heterozygotes immune to malaria is Selection for the heterozygote.

This type of selection will result in the extinction of the species as all genotypes are at a selective disadvantage is a Selection against all genotypes.

Huntington's disease is a single-gene disorder caused by a malfunctioning gene on chromosome 4. It is an autosomal dominant disease, which means that only one copy of the gene needs to be defective is a Selection against the heterozygote.

Homozygotes are organisms that have the same copy of alleles for a given trait. For example, if the allele for height is H and h where H is the allele for tallness while h is for short.

The genotype of the homozygotes will be HH or hh

Heterozygotes are organisms that have different copies of alleles for a given trait. For example, if the allele for height is H and h where H is the allele for tallness while h is for short.

The genotype of the heterozygotes will be Hh.

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The volume of the standardized base used in the titration was 23.43 mL.

When performing titration, the volume of the standardized base titrant used in the burette is read first (this value doesn't have to be 0, as it depends on the titrator filling the burette). In this case, this value is 2.75 mL.

During the titration, the titrant level in the burette goes down, and when the endpoint is reached, this level can be read. In this experiment, the final volume is 26.18 mL.

The volume used in the titration is obtained by subtracting the starting value from the final volume:

26.18 mL - 2.75 mL = 23.43 mL

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At 40°C 12.25 g potassium sulfate would be precipitated

Saturated solutions are those in which the maximum amount of solute has been dissolved. The solute precipitates out of the solution as more solute is added.

Solubility of potassium sulfate is shown as:

Solubility of potassium sulfate at 40 °C will be 15 g/100 g

It can be understand that at 40 °C 15 g of potassium sulfate would get completely dissolved in 100 of water.

46.0 g of potassium sulfate to 225 g water

Amount of potassium sulfate will get dissolve in 225 g of water at 40 °C will be:

15 g/100g ×225 g = 33.75 g

Amount of potassium sulfate precipitated by the solution can be determined by as follow:

= 39.0 g-33.75 g = 5.25 g

At 40 °C 5.25 g of potassium sulfate will get precipitate out from the solution which means that solution is saturated.

It is given that, the amount of potassium sulfate which is added :
46 g - 33.75 g = 12.25 g.

Therefore, at 40°C 12.25 g potassium sulfate would be precipitated.

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The molecular formula of diazomethane is CH₂N₂, and the main reason for its instability is precisely the fact that it can very easily evolve nitrogen, as nitrogen's triple bond is one of the strongest covalent bonds in nature, and the energy released in its formation is more than enough to compensate the energy lost in the breaking of C-N bonds. The Lewis structure of diazomethane with the formal charges is attached below.

To obtain the molecular formula of diazomethane, we can imagine that we have 100 g of it. Now we can calculate the number of moles (n) for each of the elements, using their respective masses (m) and molar masses (M = 12 g/mol for carbon, 1 g/mol for hydrogen, and 14 g/mol for nitrogen):

n = m/M

n(C) = 28.57 g / 12 g/mol

n(C) = 2.38 mol

n(H) = 4.80 g / 1 g/mol

n(H) = 4.80 mol

n(N) = 66.64 g / 14 g/mol

n(N) = 4.76 mol

We now divide each of these numbers with the smallest of them (2.38) to calculate the molar ratio of the elements:

carbon: 2.38 / 2.38 = 1

hydrogen: 4.80 / 2.38 = 2

nitrogen: 4.76 / 2.38 = 2

Now we use these numbers to get the empirical formula of diazomethane: CH₂N₂.

The molar mass of the empirical formula is:

12 g/mol + 2 * 1 g/mol + 2 * 14 g/mol = 42 g/mol

Since this value is equal to the molar mass given to us, that means that CH₂N₂ is also the molecular formula of diazomethane.

Once chewed and swallowed, the food will be digested and absorbed nutrients, while the rest of the food will be excreted through the body's feces. This digestion process can take about 24-72 hours.

The process of digestion of food in humans can be divided into two types, namely mechanical digestion and chemical (enzymatic) digestion. Mechanical digestion is the process of changing food from a large or coarse form to a smaller or finer form. The process takes place in the mouth with the help of teeth and tongue. The mechanical digestion process also occurs in the stomach with the help of peristaltic motion of the stomach wall, so that food is like being stirred. While the chemical digestion process is the process of converting food substances from complex forms into simpler forms with the help of digestive enzymes.

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The atomic number of rubidium is 37, it means that its electron configuration is as follows:

Rubidium is an alkali metal. Its ion is formed when it loses an electron. It means that the rubidium ion has 36 electrons instead of 37, and its configuration is as follows:

Answer: Physical - Color, density, boiling/melting point, magnetism, texture, and odor

Chemical - reactivity, combustibility, color change, and temperature change

Explanation:

Physical properties are changes to a substance that can be reversed and refer to its state at the time. Chemical properties are properties that are observable during or after a chemical reaction and cannot be reversed since the reaction has changed the state of the substance.

Answer:

D. 32.

Explanation:

Remember the formula of atomic mass:

If you go to see the periodic table, you can note that the atomic mass of cobalt is 58.9 amu rounded to 59 amu. Let's solve for '# neutrons' and replace the atomic mass (59) and the atomic number (27) (remember that the number of protons is the same that the atomic number), like this:

The answer would be that the number of neutrons to make a cobalt atom most stable is D. 32.

The correct answer is that a) covalent bonds need to form between molecules. The process of polymerization to polybutene doesn't require any of the other given transformations.

The polymerization process of 1-butene to polybutene includes the homolytic cleavage of the double bond and the formation of new covalent bonds between the radical formed and another molecule of 1-butene. This means that there is no need for oxidation (option b), formation of additional double bonds (option c, although the resulting molecule could also undergo polymerization, but it would not result in the formation of polybutene), or exchange of hydrogen atoms between the molecules (option d).

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Answer: A. Covalent bonds would need to form between the molecules.

Explanation: Got 100 on edmentum

Answer:

freezing points hope it helps u

Distillation is a process used to separate a mixture of liquids based on different freezing points. Therefore, option C is correct.

Distillation is the process of turning a liquid into a vapor, which is then condensed back into a liquid state. The simplest illustration of it is when steam from a kettle condenses into drops of distilled water that are left on a cold surface.

In general, distillation is the process of vaporizing a liquid to its boiling point, then condensing it back into a liquid to separate it from impurities or other solutes.

Among the many industrial uses of distillation are the production of alcoholic drinks, water purification, and oil refining. Distillation is a physical procedure that removes desired pure compounds from an initial source using heat and other techniques.

Thus, option C is correct.

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Option C is correct. reduce reactant concentrations. shorten the time the reaction is allowed to proceed.

The reaction rate normally increases as the temperature rises. With rising temperature, the average kinetic energy of the reactant molecules rises. The minimum energy needed for an effective collision will therefore be present in a higher percentage of molecules. With rising temperatures, molecules' kinetic energy rises. The possibility of a reaction rises as molecules move more quickly and collide more frequently. This speeds up the reaction. The average kinetic energy of the individual particles of the system increases with increasing temperature. Particles move faster and collide more often per unit time as the average kinetic energy increases, and they have more energy when they collide. Both of these factors speed up the reaction.

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The number of moles added to increase the volume of the gas from 8.51 L to 15.5 L is 8.67 moles.

The initial volume of the gas is 8.15 L and final volume of gas is 15.5 L and the initial moles are 9.51 moles.

As per the Ideal gas equation,

PV = nRT

where,

P is pressure,

V is volume of gas,

n is the number of moles of gas,

R is the gas constant,

T is the temperature of the gas.

Rearranging the equation,

V/n = RT/P

The left side is constant, so, it is valid to see,

V₁/n₁ = V₂/n₂

V₁ is initial volume,

n₁ is the initial moles,

V₂ is the final volume,

n₂ is the final moles.

So, we can write this by putting the values,

8.51/(9.5) = 15.5/n₂

n₂ = 18.17

The number of moles added = n₁ - n₂

Added moles = 8.67 moles

The moles added are 8.67 moles.

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The second element in group 2 has an atomic number of 12.

We can describe atomic number as the number of protons that are present in the nucleus of an atom. The number of protons is equal to the number of electrons, hence the atomic number is the number of protons or the number of electrons in an atom.

Beryllium has an atomic number of 4 because the element Beryllium has 4 protons.

In the periodic table, you will find that the second element in group 2 is Magenium. The atomic number of Magnesium is 12 because Magnesium has 12 protons in the nucleus of its atom.

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Answer:

Option B is the right answer.

Based on the dissociation of each of the given salts, we can calculate that there are b. 51.5 g of chloride ions per liter of the solution.

Each mol of calcium chloride (CaCl₂) dissociates to give 2 moles of chloride ions. The number of moles of chloride ions that comes from calcium chloride is:

2 * 0.200 mol = 0.400 mol

Each mol of magnesium chloride (MgCl₂) dissociates to give 2 moles of chloride ions. The number of moles of chloride ions that comes from magnesium chloride is:

2 * 0.150 mol = 0.300 mol

Each mol of sodium chloride (NaCl) dissociates to give 1 mol of chloride ions. The number of moles of chloride ions that comes from sodium chloride is thus 0.750 mol

The total number of moles (n) of chloride ions in the solution is:

n = 0.400 mol + 0.300 mol + 0.750 mol

n = 1.450 mol

Now, we can use the molar mass of the chloride ion (M = 35.5 g/mol) to calculate the mass (m) of chloride ions in 1 liter of solution:

n = m/M ⇒ m = n*M

m = 1.450 mol * 35.5 g/mol

m = 51.475 g

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Answer

%Yield = 87.2%

Explanation

Given:

mass of NH3 reacted = 73 g

mass of H2O produced = 101 g

We know:

molar mass of NH3 = 17,031 g/mol

molar mass of water = 18.01528 g/mol

Required: % Yield

Solution:

The formula used to calculate the percentage yield is:

%Yield = (actual yield/theoretical yield) x 100

The actual yield of H2O produced = 101 g

Now lets calculate the theoretical yield first.

First find the number of moles of NH3, and use stoichiometry to find the theoretical mass of water.

n = m/M n is the moles, m is the mass and M is the molar mass.

n = 73/17,031 g/mol

n = 4.29 mol

Using the stoichiometry, there molar ratio between NH3 and H2O is 4:6

Therefore the moles of H2O = 4.29 x (6/4)

n of H2O = 6.43 mol

The theoretical mass can then be calculated:

m = n x M

m = 6.43 mol x 18.01528 g/mol

m = 115.83 g

%Yield = (101 g/115.83)*100

%Yield = 87.2%

By using the balanced reaction equation of ethane combustion, we can calculate that 12.8 L of carbon dioxide will be produced.

To calculate the answer to this, we need to write the balanced reaction equation:

2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O

Based on this, we can see that 2 moles of ethane produce 4 moles of carbon dioxide. Now, we need to calculate the number of moles (n) of ethane using its mass (m = 8.00 g) and its molar mass (M = 30.07 g/mol):

n = m/M

n = 8.00 g / 30.07 g/mol

n = 0.266 mol

Based on this, we can conclude that 2 * 0.266 mol = 0.532 mol of carbon dioxide was produced. Assuming that carbon dioxide acts as an ideal gas, we can use the ideal gas equation to calculate its volume:

PV = nRT ⇒ V = nRT/P

V - the volume of the gas

n - number of moles of gas (0.523 mol)

R - universal gas constant (0.08206 L*atm/K*mol)

T - temperature in Kelvins (25 °C = 298.15 K)

P - pressure (1.00 atm)

Now we plug all the known values into the equation:

V = 0.523 mol * 0.08206 L*atm/K*mol * 298.15 K / 1.00 atm

V = 12.8 L

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The molarity of the chemical X is 11.65 M.

To calculate the molarity (c) of the solution, we need the number of moles (n) of substance X and the volume (V) of the solution. We can assume that we have 100 mL = 0.1 L of the solution. Now we have the volume, and we can use it to calculate the mass (m) of the solution using its density (d = 1.18 g/mL):

d = m/V ⇒ m = d * V

m = 1.18 g/mL * 100 mL

m(solution) = 118 g

From this, we can obtain the mass of substance X using the mass percentage (%w = 36% = 0.36):

m(X) = %w * m(solution)

m(X) = 0.36 * 118 g

m(X) = 42.48 g

Now that we have the mass of X, we divide it by its molar mass (M = 36.46 g/mol) to obtain the number of moles:

n = m/M

n = 42.48 g / 36.46 g/mol = 1.165 mol

Finally, we calculate the molarity of the solution:

c = n/V

c = 1.165 mol / 0.1 L = 11.65 M

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First, let's write the balanced chemical reaction:

2 H2O2 ---MnO2--> 2 H2O + O2

This reaction is a b. Decomposition Reaction of hydrogen peroxide.

Step 1. Let's transform 2.11 mg of H2O2 into moles using the following equation mole = mass / molar mass

Step 2. We are going to use the equation proportion to calculate the quantity in moles of each compound.

Step 3. We are going to transform moles into grams of each compound using the following equation: mass = mole x molar mass

Step 1.

We need to transform 2.11 mg to g. We just need to divide by 1000,

So: 2.11 x 10^-3 g of H2O

mole = 2.11 x 10^-3/34.02

mole = 6.20 x 10^-5 moles

Step 2.

2 moles of H2O2 ---- 2 moles of H2O

6.20 x 10^-5 moles ---- x moles of H2O

x = 6.20 x 10^-5 moles of H2O

2 moles of H2O2 ---- 1 moles of O2

6.20 x 10^-5 moles ---- x moles of O2

x = 3.10 x 10^-5 moles of O2

Step 3.

molar mass of O2 : 32 g/mol

molar mass of H2O: 18 g/mol

mass of H2O = 6.20 x 10^-5 x 18 = 1.12 x 10^-3 g

mass of O2 = 3.10 x 10^-5 x 32 = 9.92 x 10^-4 g

Answer:

see the explanation

Explanation:

1. IV

2. VI

3. II

4. IV

5. II

6. VI

7. IV

8. III

9. II

10. I

11. I

12. V

13. VII

14. III

15. I

16. III

17. V

18. IV

19. V

20. III

21. IV

22. III

23. IV

24. VII

25. II

26. II

27. III

The heat released by metal and added to water is the same which is 1039.83 joule.

The equilibrium condition of the system depends on the heat released from both gold and water. The total heat received by the system will equal to total heat released by objects. It should follow

Q released = Q received

The heat can be defined by

Q = m . c . ΔT

where Q is heat, m is mass, c is the specific heat constant and ΔT is the change in temperature.

The given parameters are

m = 17.27 g = 0.01727 kf

T1 = 92 ⁰C

T2 = 25.1 ⁰C

c = 900 J/kg⁰C

By substituting the given parameters, we can calculate the heat

Q = m . c . ΔT

Q = 0.01727 . 900 . (92 - 25.1)

Q = 1039.83 joule

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In first place, the balanced reaction is:

Fe₂O₃ + 3 CO → 2 Fe + 3 CO₂

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

The molar mass of the compounds is:

Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:

The limiting reagent is one that is consumed first in its entirety, determining the amount of product in the reaction.

To determine the limiting reagent, it is possible to use a simple rule of three as follows: if by stoichiometry 84 grams of CO reacts with 159.7 grams of Fe₂O₃, 13.4 grams of CO reacts with how much mass of Fe₂O₃?

mass of Fe₂O₃= (13.4 grams of CO× 159.7 grams of Fe₂O₃)÷ 84 grams of CO

mass of Fe₂O₃= 25.476 grams

But 25.476 grams of Fe₂O₃ are not available, 11.7 grams are available. Since you have less mass than you need to react with 13.4 grams of CO, Fe₂O₃ will be the limiting reagent.

The theoretical yield is the maximum amount of product that could be formed from the given amounts of reagents.

Considering the limiting reagent, the following rule of three can be applied: if by reaction stoichiometry 159.7 grams of Fe₂O₃ form 111.7 grams of Fe, 11.7 grams of Fe₂O₃ form how much mass of Fe?

mass of Fe= (11.7 grams of Fe₂O₃×111.7 grams of Fe) ÷159.7 grams of Fe₂O₃

mass of Fe= 8.183 grams

Then, the theoretical yield of Fe is 8.183 grams.

The percent yield is the ratio of the actual return to the theoretical return expressed as a percentage.

The percent yield is calculated as the experimental yield divided by the theoretical yield multiplied by 100%:

percent yield= (actual yield÷ theoretical yield)×100%

In this case, you know:

Replacing in the definition of percent yield:

percent yield= (7 grams÷ 8.183 grams)×100%

Solving:

percent yield= 85.54%

Finally, the percent yield is 85.54%.

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The incorrect statement is, "reaction rate is the speed at which the reaction proceeds towards equilibrium".

The rate of the reaction is defined as the rate at which the reaction is taking place.

It is true that the rate of reaction is governed by the energy barrier between the reactant and the products.

Enzymes are special compounds which can accelerate the rate of reaction.

The rate of reaction is independent of the rate of temperature of the system. The rate of reaction depends on the concentration of the reactants.

Rate of the reaction is directly proportional to the increase in concentration of products.

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Answer: protons: 92

electrons: 92

1. neutrons: 234-92 = 142

2. Neutrons- 233-92 = 141

3. Neutrons 232-92= 140

Explanation:

        The difference between a kelvin (K), which is a division of the kelvin scale, and a degree on the Celsius scale is where zero is. The zero point on the Kelvin scale is at absolute zero, whereas the zero point on the Celsius scale is the freezing point of water. As a result, 0oK equals -273.15oC and 0oC equals 273.15 kelvins.

Answer : C.933.45K

         At 0 degrees Celsius, or 273 Kelvin, water freezes. Also, -273 degrees Celsius are the same as 0 Kelvin. Therefore, multiply the Celsius degree by 273 to convert it to Kelvin. And to convert from Kelvin to Celsius, just take 273 out.

Celsius to Kelvin conversion: Kelvin = Celsius + 273 1.5. The figure of 273 is also used instead of 273.15

Solution :

K = ° C + 273.15

K = 660.3 + 273.15

K = 933.45

Answer :660.3°C = 933.45k

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The Ka value of a protonated base is the acid ionization constant. Which can be calculated from the concentration of H+ ion and the conjugate base. The ka value of protonated urea of the given pH is 7.92 ×10⁻¹⁵.

pH of a solution is the measure of its H+ ion concentration. It is says how much acidic or basic the solution is. If the pH value is 7, then the solution is neutral and if it is less than 7 the solution is acidic. pH value greater than 7 indicates that the solution is basic.

pH of a solution mathematically is the negative logarithm of H+ ion concentration. Given that the pH of urea solution is 7.050. Thus its H+ ion concentration is calculated as follows;

-7.050 = log [H+]

[H+] = antilog (-7.050)

       = 8.9 × 10⁻⁸

Now when the protonated urea say it as HA is dissociated into its ions H+ and A-, then the ka value is written as;

[tex]Ka = \frac{[H+][A-]}{[HA]}[/tex]

Here, the [H+] and A- ion concentrations are equal and concentration of the solution HA is given 1 M.

Thus, Ka value of protonated urea can be calculated as follows:

Ka =  (8.9 × 10⁻⁸)² / (1-[ 8.9 × 10⁻⁸])

    = 7.92 ×10⁻¹⁵

Therefore, the acid ionization constant Ka of 1 M protonated urea with a pH of 7.050 is 7.92 ×10⁻¹⁵.

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Experimental pH indicates the pH obtained by directly measuring a specific sample with a pH meter.

The main difference between calculated and experimental pH is that calculated pH gives the pH obtained by solving the pH equation whereas experimental pH is measured directly with a pH meter. It is to indicate the value of a particular sample obtained.

Because microorganisms such as bacteria are sensitive to the concentration of hydrogen ions present in the environment, pH results will change over the course of an experiment. pH is affected by larger proteins, including enzymes. pH is a quantitative measure of the acidity or basicity of a solution while acidity is a qualitative measure of the acidic properties of a solution.

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Answer:

2.068

Explanation:

D = M/V

3.04 /1.47

= 2.068

An physical properly I believe

Explanation: characteristics such as melting point boiling point color ider colored stuff etc all have physical properties