Please help with my chemistry homework

We have that, the skin has pigment that protects from the sun(Melanin) but excess exposure can still cause serious damage.

Generally, Sunlight exposures can be a double edge sword as it provides one of the essential vitamins needed by the body to thrive(vitamin D), anon the other hand it still holds Heat energy which exess exposure to can cause ones  burns and destruction

Therefore

We say that over heating by sunlight can damage lots of things from skin, set fires. The skin has pigment that protects from the sun(Melanin) but excess exposure can still cause serious damage.

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Answer:

one valence electron

Lithium has a single electron in the second principal energy level and so we say that lithium has one valence electron. Beryllium has two valence electrons.

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Answer:

one

Explanation:

because lithium is the third element with a total of 3 electrons.

Answer:

Strontium

Explanation:

strontium will be less reactive because reactivity decreases down the group

Explanation:

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arrow_backSources of Information on Modern Indian History

Summary

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References

A primary source of information for historians is the official records of the British administration. The British kept written records of every key instruction, meeting, transaction, investigation, plan, policy decision and agreement. They attached record rooms with all the important administrative institutions.

The British built specialized institutions like museums and archives to preserve important documents.

Historians gather important information about the provincial administrative system from the reports, memos, notings and letters preserved in the 19th century in the archives and record rooms across India.

For effective administration, the British carried out a number of surveys in the early 19th century.

By the end of the 19th century, censuses of all the Indian provinces were being carried out every ten years. This helped to collect information on the religion, caste and occupation of the people. These surveys have helped historians to collect information about modern India.

Personal diaries of personalities like Jawaharlal Nehru and Sardar Vallabhbhai Patel, newspapers, popular books like The Discovery of India and Glimpses of World History, autobiographies of personalities like Mahatma Gandhi, and accounts of travellers and pilgrims give a deep insight into the lives of the common people.

Answer:Stable nuclei with atomic numbers up to about 20 have an neutron:proton ratio of about 1:1 (solid line). Figure 1: permission from Wikipedia. The deviation from the N:Z=1 line on the belt of stability originates from a non-unity N:Z ratio necessary for total stability of nuclei

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Answer: Copper

Explanation: A material's ability to form thin sheets under pressure by hammering or rolling is called Malleability.Metallic bond is a term used to describe the collective sharing of a sea of valence electrons between several positively charged metal ions.Metallic bonding is a type of chemical bonding that arises from the electrostatic attractive force between conduction electrons (in the form of an electron cloud of delocalized electrons) and positively charged metal ions.A strong metallic bond will be the result of more delocalized electrons, which causes the effective nuclear charge on electrons on the cation to increase, in effect making the size of the cation smaller. Metallic bonds are strong and require a great deal of energy to break, and therefore metals have high melting and boiling points

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Yes,  there actually two kinds of outer atom positions in octahedral geometry.

The octahedral geometry has to do with an arrangement of six groups around the central atom in a compound. We know that for the complexes that do have the octahedral geometry, we have a square that has all the atoms that are in the plane of the square as equivalent.

Now, above and below the plane, we have two axial bonds that tend to be longer than the rest of the bonds that are in the plane of the square and these longer bonds re quite less strong than the bonds that are in the plane of the square.

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The use of cold ethanol instead of hot ethanol in recrystallization would hinder the dissolution process, result in slower crystal formation, and compromise the purity of the final product. Therefore, it is essential to follow the appropriate recrystallization procedure using hot ethanol to obtain the desired results.

The process of recrystallization involves dissolving a solid in a suitable solvent and then allowing it to crystallize out under controlled conditions. The choice of solvent and temperature is crucial in achieving successful recrystallization. In the given scenario, if cold ethanol is used instead of hot ethanol, the process of recrystallization may not work effectively for several reasons.

Firstly, ethanol has a lower solubility for many compounds at lower temperatures. Cold ethanol may not be able to dissolve the compound completely, leading to incomplete or inefficient recrystallization. The purpose of recrystallization is to obtain pure crystals, free from impurities. If the compound is not dissolved adequately, impurities may remain trapped, resulting in impure crystals.

Secondly, the rate of crystal formation is significantly slower at lower temperatures. By using hot ethanol, the solvent's increased kinetic energy allows for faster dissolution and subsequent recrystallization. Cold ethanol would not provide the same level of energy, leading to slower crystallization kinetics. This slower process increases the chances of impurities being trapped within the crystal lattice, diminishing the purity of the final product.

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The correct option is $26785.To calculate the total cost per equivalent unit using the weighted average method, we need to consider the costs incurred in both the beginning work in process and the units added during the period.

First, let's calculate the equivalent units of production for both conversion and materials:

Conversion costs:

Beginning work in process: 400 units × 20% complete = 80 equivalent units

Units added during the period: 2,000 units × 40% complete = 800 equivalent units

Total equivalent units for conversion = 80 + 800 = 880 equivalent units

Material costs:

Beginning work in process: 400 units × 30% complete = 120 equivalent units

Units added during the period: 2,000 units × 50% complete = 1,000 equivalent units

Total equivalent units for materials = 120 + 1,000 = 1,120 equivalent units

Next, let's calculate the total costs incurred:

Conversion costs:

Beginning work in process cost: $14,880

Costs added during the period: $409,200

Total conversion costs = $14,880 + $409,200 = $424,080

Material costs:

Beginning work in process cost: $9,900

Costs added during the period: $180,080

Total material costs = $9,900 + $180,080 = $189,980

Now, we can calculate the total cost per equivalent unit:

Total cost per equivalent unit = (Total conversion costs + Total material costs) / (Total equivalent units for conversion + Total equivalent units for materials)

Total cost per equivalent unit = ($424,080 + $189,980) / (880 + 1,120)

Total cost per equivalent unit ≈ $267.85

Therefore, the correct option is $26785.

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Explanation:

No because the person on the bike is going faster then the person on foot.

The correct options are: The boiling point is the temperature at which the vapor pressure equals the external pressure and Boiling occurs when the vapor pressure of the liquid is sufficient for bubbles of vapor to form in the interior of the liquid.

The first option is a fundamental concept in thermodynamics and describes the point at which a liquid changes into a gas. At the boiling point, the vapor pressure of the liquid becomes equal to the external pressure, causing the liquid to boil and turn into a gas. The boiling point is a unique property of a substance and can be used to identify and characterize it.

The second option is a description of the process by which boiling occurs. Boiling occurs when the vapor pressure of the liquid exceeds the external pressure and bubbles of vapor form in the interior of the liquid. These bubbles then rise to the surface and escape into the atmosphere. The temperature at which boiling occurs is the boiling point.

The other options are incorrect. A substance with strong intermolecular forces will have a high boiling point, not a low one. The boiling point of a substance increases as the external pressure decreases, not increases. Finally, while evaporation is a related process, it is not the same as boiling, which involves the entire volume of the liquid changing to a gas.

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Answer:

the volume of 4.59 mole of co2 gas at stp is 103L

The substance in the image above would be classified as a mixture of elements (option E).

A compound is a substance formed by chemical bonding of two or more elements in definite proportions by weight.

On the other hand, a mixture is made when two or more substances are combined, but they are not combined chemically.

According to this question, an image is shown with two different substances or elements as distinguished by coloration (white and purple). These elements are combined but not chemically bonded, hence, is a mixture.

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C₇H₅O²⁻ is basic; I⁻ is neutral ; NO₃⁻ is neutral; F⁻ is basic.

(a). C₇H₅O²⁻ is basic because the anion can act as a base by accepting a proton (H+) from water, forming benzoic acid and hydroxide ion:

C₇H₅O²⁻ + H₂O ⇌ C₇H₆O₂ (benzoic acid) + OH⁻

(b). I⁻ is neutral. The anion does not have the ability to accept or donate protons.

(c). NO₃⁻ is neutral. The anion does not have the ability to accept or donate protons.

(d). F⁻ is basic. The anion can act as a base by accepting a proton (H+) from water, forming hydrofluoric acid and hydroxide ion:

F- + H₂O ⇌ HF (hydrofluoric acid) + OH⁻

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Answer:

Explanation:

Here, we want to get the number of moles of NO gas that can be formed

To answer this, we need to be sure of the limiting reagent

The limiting reagent is the one that is responsible for the number of moles of product formed

From the shown balanced equation of reaction, 3 moles of silver produced 1 mole of the gas

Thus, 0.1 mol of powdered silver will produce:

For the nitric acid, we need to get the number of moles that reacted

To get this, we have to multiply the volume (in L) that reacted by the molarity

Mathematically, we have that as:

From the equation of reaction, 4 moles of the nitrate gave 1 mole of the gas

Thus, we have it that 0.06 moles will give:

From what we see, the number of moles produced by the nitrate is less than what was produced by the solid

Thus, the nitrate is the limiting reagent and the number of moles of the gas produced is 0.015 mol

Hydrogens are removed from polyprotic acids through a stepwise dissociation process. Each hydrogen ion (H+) removed one at a time, resulting in formation of successive conjugate bases.

Strength of acid decreases with each removal of a hydrogen ion. The Ka (acid dissociation constant) of a polyprotic acid represents the equilibrium constant for the dissociation of the first hydrogen ion. The Ka value is related to the acidity of the acid. As the Ka value increases, the acid is stronger and more likely to donate its hydrogen ion. In the case of polyprotic acids, the Ka value decreases with each successive dissociation of a hydrogen ion. This is because the dissociation of subsequent hydrogen ions becomes progressively more difficult as the acid loses its positive charge and the electron density on the remaining oxygen atoms decreases.

The Kb (base dissociation constant) values are related to the Kb values of the conjugate bases of the polyprotic acids. The relationship between Ka and Kb is defined by the equation Ka x Kb = Kw, where Kw is the ion product of water. Knowing the Kb value of the conjugate base, one can determine the Ka value of the corresponding acid by using this equation. The relationship between Ka and Kb values reflects the principle of equilibrium. In an acid-base reaction, the equilibrium constant for the forward reaction (Ka) is inversely proportional to the equilibrium constant for the reverse reaction (Kb). Therefore, if the Kb value of a conjugate base is known, one can calculate the Ka value of the acid by using the equation Ka = Kw / Kb.

Overall, the relationship between Ka, Kb, and the stepwise dissociation of polyprotic acids provides insights into the acidity of the acid, the strength of its conjugate base, and the equilibrium between the acid and its conjugate base.

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Answer:

sentence 2, sentence 2, sentence 1

Explanation:

it was right for me on edge 2020

Answer:

1. Fred visited Nick after his graduation.

2. After Nick's graduation, Fred visited him.

1. Marie told Sarah that she makes great spaghetti.

2. Marie told Sarah, "You make great spaghetti."

1. John broke the fence with his bike.

2. John's bike hit a fence and it broke.

The molecule ammonium lauryl sulfate is a detergent because of its hydrophobic tail and a hydrophilic head which are responsible for its cleansing action.

Though not shown, I presume that the property labelled as C must have to do with the cleasing action of the molecule ammonium lauryl sulfate.

The substance has a hydrophobic tail and a hydrophilic head which enables it to form miscles and these are the responsible for the cleansing action of the ammonium lauryl sulfate molecule.

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fire in a circle

Explanation:

bc

Burning coal cause acid precipitation to enter the air.

Acid rain is defined as all kinds of rain with a pH below 5.6. Rain is naturally acidic (pH slightly below 6) because carbon dioxide (CO2) in the air which dissolves with rainwater has the form a weak acid . This type of acid in rain is very useful because it helps dissolve the minerals in the soil which are needed by plants and animals.

Acid rain is caused by Sulfur which is an impurity in fossil fuels as well as nitrogen in the air which reacts with oxygen to form sulfur dioxide and nitrogen oxides. These substances diffuse into the atmosphere and react with water to form sulfuric acid and nitric acid which are easily soluble so that they fall with the rainwater. This acidic rainwater will increase the acidity of the soil and surface water which will prove harmful to fish and plant life. Efforts to overcome this are currently being intensively implemented.

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Answer: A mole is a chemical unit to measure mass of substance.

Explanation:

A mole can be defined as 6.02214076 × 1023 of atoms, ions, molecules and others. A mole is the total amount of discrete entity within a substance present in the form of atoms, ions, and molecules. As atoms, ions, molecules are small entities within any substance so it is necessary to measure each of them and recognize them so the scientists development the concept of mole. It is the convenient unit of measurement because of the presence of greater number of molecules, atoms, and ions present in any substance.

Answer:

The mole is an SI unit used to measure the amount of any substance. One mole is exactly 6.02214076×10 23 particles.

Explanation:

The concept of the mole is important for scientists because it means that one mole of any element has exactly the same number of atoms as one mole of any other element. This information allows chemists to count atomic particles for even very complex chemistry formulas and reactions.

Answer:

For reactants : Water , Carbon Dioxide ,  Sunlight

But for products :  Oxygen , Glucose

Explanation:

A man earned a $7,500 commission by selling a coin-operated laundry business, which has six more years before the expiration of its present lease. To evaluate whether or not this sale was worth it, we must calculate the total amount of money that the laundry business will generate in the remaining six years of its current lease.

This can be calculated as follows: Monthly revenue from laundry business = $2,500Commission paid to man = $7,500Revenue generated in one year = Monthly revenue x 12 = $2,500 x 12 = $30,000Revenue generated in six years = Revenue generated in one year x 6 = $30,000 x 6 = $180,000Therefore, the laundry business will generate $180,000 in the remaining six years of its lease. Given that the man earned a $7,500 commission by selling the business, this sale was definitely worth it as the amount of money generated from the business in the remaining six years of its lease far exceeds the commission paid to the man.

The man earned a $7,500 commission by selling a coin-operated laundry business that still had six years remaining on its current lease. To determine whether this sale was worthwhile, we must first calculate the amount of money the laundry business will generate during the remaining six years of its current lease. We can do this by determining the laundry business's monthly revenue and multiplying it by 12 to get the yearly revenue.

After that, we can multiply the yearly revenue by 6 to obtain the total revenue for the next six years.Since the monthly revenue from the laundry business is $2,500, the yearly revenue is $30,000 (2,500 x 12 = 30,000). The business will earn $180,000 in the six years remaining on its lease (30,000 x 6 = 180,000).Given that the man received $7,500 in commission by selling the business, we can determine that this was a profitable sale since the total revenue generated from the business in the next six years far exceeded the commission paid to the man.

It is clear that selling the coin-operated laundry business was worth it since the total revenue generated in the remaining six years of the lease was $180,000, whereas the man earned only $7,500 in commission for selling the business. This demonstrates that this was a profitable sale and an excellent business decision.

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The man in question is a commission-based sales agent who earned $7,500 by selling a coin-operated laundry business. The laundry business is still leased for another six years before the lease expires.This information alone is insufficient to make any meaningful conclusions about the man in question.

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Answer:

Answer:- Density of the substance is 0.7

i believe

The formula for the volume of a rectangular solid is Volume = length * width * height, or V = lwh.

Converting to cm = \( \frac{660}{10} = 66 {cm}^{3 } \\ \)

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Answer:

11.009306 or 11.009

Explanation:

boron 11 has atomic mass of 11.009306

Answer:

it's volume also decrease

If a chemical reaction has a negative AH and a negative AS, then it will be spontaneous at low temperatures and non-spontaneous at high temperatures.

The spontaneity of a reaction is determined by the sign and magnitude of the change in Gibbs free energy (G). The equation for calculating Gibbs free energy is:

ΔG = ΔH - TΔS

where H is the change in enthalpy, T is the temperature in kelvins, and S is the change in entropy.

When G is negative, the reaction is spontaneous.

When G is positive, the reaction is non-spontaneous.

When G is zero, the reaction is at equilibrium. If a chemical reaction has a negative H and a negative S, then the formula for Gibbs free energy becomes:

G = H - TS = (-) - T(-) When T is low, -TS will be small, so G will be negative, and the reaction will be spontaneous.

When T is high, -TS will be large, so G will be positive and the reaction will be non-spontaneous.

Therefore, the answer is D

It will be spontaneous at low temperatures and non-spontaneous at high temperatures.

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