UV-B light is harmful to the human body and can cause irreparable cell damage. How much energy per photon is associated with UV-B rays with a wavelength of 305 nm?

Answers

Answer 1

The energy of the waves is 6.5 * 10^-19 J.

What is the energy?

The energy of the wave could be obtained from the wavelength of the wave by by the use of the formula shown below;

E = hc/λ

h = Plank's constant

c = speed of light

λ = wavelength

Now we have;

h = 6.6 * 10^-34 Js

c = 3 * 10^8 m/s

λ =  305 * 10^-9

E =  6.6 * 10^-34 Js * 3 * 10^8 m/s/ 305 * 10^-9

E = 6.5 * 10^-19 J

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Related Questions

Which substances are subject to avogadro law?​

Answers

Answer:

Avogadro's law (sometimes referred to as Avogadro's hypothesis or Avogadro's principle) is an experimental gas law relating the volume of a gas to the amount of substance of gas present.[1] The law is a specific case of the ideal gas law. A modern statement is:

Avogadro's law states that "equal volumes of all gases, at the same temperature and pressure, have the same number of molecules."[1]

For a given mass of an ideal gas, the volume and amount (moles) of the gas are directly proportional if the temperature and pressure are constant.

The law is named after Amedeo Avogadro who, in 1812,[2][3] hypothesized that two given samples of an ideal gas, of the same volume and at the same temperature and pressure, contain the same number of molecules. As an example, equal volumes of molecular hydrogen and nitrogen contain the same number of molecules when they are at the same temperature and pressure, and observe ideal gas behavior. In practice, real gases show small deviations from the ideal behavior and the law holds only approximately, but is still a useful approximation for scientists.

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Which chemical reaction involves the fewest oxygen atoms?

A. 2AgNO3 + K2SO4 → Ag2SO4 + 2KNO3

B. 4Fe + 6H2O + 302 4Fe(OH)3

C. 6CO2 + 6H20 - C6H12O6 + 602

D. C2H4 + 302 - 2CO2 + 2H2O​

Answers

Answer:

4Fe + 6H2O + 3O2 -------> 4Fe(OH)3

Explanation:

The chemical reaction involves the fewest oxygen atoms is 4Fe + 6H2O + 302 4Fe(OH)3. Therefore, option B is correct.

What is chemical reaction ?

The chemical reaction, the transformation of one or more chemicals (the reactants) into one or more distinct compounds (the products). Chemical elements or chemical compounds make up substances.

When atoms establish or break chemical bonds, chemical processes take place. Reactants are the substances that begin a chemical reaction, while products are the compounds that are created as a result of the reaction.

We can learn about a substance's qualities by studying chemical reactions. We can learn about a substance's chemical characteristics by looking at how it interacts with other substances. These characteristics can be utilized to recognize an unidentified sample.

Thus, option B is correct.

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barium chloride + sodium phosphate 
Answer with double displacement

Answers

Answer:

Barium chloride + Sodium phosphate    →   barium phosphate + sodium chloride

Explanation:

Double replacement:

It is the reaction in which two compound exchange their ions and form new compounds.

AB + CD → AC +BD

Chemical equation:

BaCl₂ + Na₃PO₄         →     Ba₃(PO₄)₂ + NaCl

Balanced chemical equation:

3BaCl₂ + 2Na₃PO₄         →     Ba₃(PO₄)₂ + 6NaCl

The cation and anion of both reactants are exchanged with each other.

Ba²⁺ react with PO₄³⁻ and form Ba₃(PO₄)₂ while Cl⁻ react with Na⁺ and form sodium chloride.  

Molecular equation:

Barium chloride + Sodium phosphate    →   barium phosphate + sodium chloride

If the specific heat of water is 4.184 J/g∙°C, how much heat is required to increase the temperature of 1.500g of water from 23 °C to 39 °C? (show your work) Units count

Answers

Answer:

Q = 100.42 J

Explanation:

Given data:

Mass of water = 1.500 g

Specific heat capacity of water = 4.184 J/g.°C

Heat required = ?

Initial temperature = 23°C

Final temperature = 39°C

Solution:

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

ΔT = 39°C - 23°C

ΔT = 16°C

Q = 1.500 g× 4.184 J/g.°C  ×16°C

Q = 100.42 J

Based on the information that is given, which atom is the table ?

Answers

Answer:

The one with the greatest mass would be the one that has the most things in the nucleus, protons and nutrons

Explanation:

Every cell in an organism has the same number of chromosomes, except:
A.)Skin cells
B.)Neurons
C.)White blood cells
D.)Reproductive cells

Answers

Answer: omg this is so old! :D but its D!

Explanation:

The cells that has been composed of the indifferent number chromosomes as compared to other cells have been reproductive cells. Thus, option D is correct.

Cells have been the smallest and the unit of life. The cells have been composed of the pairs of chromosomes in higher organisms. There has been the presence of 46 chromosomes i.e. 23 pairs of chromosome. However, the chromosomes in the cell have been diploid i.e. in set of 2.

The reproductive cells have been resulted in the formation of the new cells. So they have been consisted of the cells with the half the number of chromosomes and are haploid in nature.

Thus, the cells that have different number of chromosomes as compared to the other cells have been reproductive cells. Thus, option D is correct.

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Which atom would be expected to have a half-filled 6s subshell

Answers

Answer: I think the answer is Cesium (Cs)

Explanation:

A half-filled 6s subshell would be 6s^1

Calculate the molar mass of menthol, C10H20O

Answers

Answer:

C10H200

Explanation:

The molecular formula C10H20O (molar mass : 156.27 g/mol) may refer to: Citronellol. Decanal.

The molar mass of menthol ([tex]\rm C_10H_{20}O[/tex]) is 156.3 g/mol.

To calculate the molar mass of menthol ([tex]\rm C_10H_{20}O[/tex]), we need to determine the sum of the atomic masses of all the individual atoms in the compound.

The atomic masses of the elements are as follows:

C (carbon) = 12.01 g/mol

H (hydrogen) = 1.01 g/mol

O (oxygen) = 16.00 g/mol

Now, let's calculate the molar mass of menthol:

Molar mass of menthol = (10 * molar mass of C) + (20 * molar mass of H) + (1 * molar mass of O)

                      = (10 * 12.01 g/mol) + (20 * 1.01 g/mol) + (1 * 16.00 g/mol)

                      = 120.1 g/mol + 20.2 g/mol + 16.0 g/mol

                      = 156.3 g/mol

Therefore, the molar mass of menthol ([tex]\rm C_10H_{20}O[/tex]) is 156.3 g/mol.

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You are given 10ml (M) 20 Naoh solution in a conical flask and asked to titrate with (M) 20 Hcl and (M) 20 H2so4 separately. calculate the moles of Hcl and H2so4 required to neutralize the Naoh solution

Answers

Answer:

[tex]n_{HCl}=0.2molHCl\\n_{H_2SO_4}=0.1molH_2SO_4[/tex]

Explanation:

Hello!

In this case, since the reactions between NaOH and the acids are:

[tex]NaOH+HCl\rightarrow NaCl+H_2O\\\\2NaOH+H_2SO_4\rightarrow Na_2SO_4+2H_2O[/tex]

Whereas we can see the 1:1 and 2:1 mole ratios between NaOH and HCl and H2SO4 respectively. In such a way, at the equivalence point we realize that:

[tex]n_{HCl}=n_{NaOH}=V_{NaOH}M_{NaOH}=0.01L*20mol/L=0.2molHCl\\\\2n_{H_2SO_4}=n_{NaOH}\\\\n_{H_2SO_4}=\frac{1}{2} V_{NaOH}M_{NaOH}=\frac{0.01L*20mol/L}{2} =0.1molH_2SO_4[/tex]

Best regards!

What must be known for the rate constant to be calculated from the rate law?

A. The temperature at the beginning if the reaction
B. The reaction rate at known product concentrations
C. The reaction rate at known reaction concentrations
D. The activation energy the reaction must overcome​

Answers

Answer:

C. The reaction rate at known reaction concentrations

Explanation:

The rate of a reaction is the measure of the speed of a chemical reaction. To find the rate constant of a reaction, the concentration of the reactants must be known.

Reaction rate is directly proportional to the concentration of the reactants. The quantitative relationship between the rate of a reaction and the concentrations of reactants is expressed as the rate law. From this we can deduce the rate constant.

Answer:

C. ApE x Approved

Explanation:

Trust

What volume of 0.26 M H2SO4 can be prepared by diluting 125 mL of 5.1 M H2SO4?

______L

Answers

Answer:

2451.9 ml

Explanation:

M1V1 = M2 V2

M1 = 5.1M

V1 = 125ml

M2=0.26M

V2= ?

V2= M1 V1/M2

V2 = 5.1*125/0.26

V2 = 2451.9 ml

the burning of fossil fuels produces what kind of energy​

Answers

Answer:

When fossil fuels are burned carbon and hydrogen react with oxygen in air to carbon dioxide (CO2) and water (H2O). During this reaction heat is released which further amplifies the reaction. Electricity is generated by transforming mechanical energy (heat) to electrical energy in a turbine or generator.

Explanation:

What does it mean for a gene to be active?

Answers

Answer: You should be able to find the answer on the internet

When a gene is active, the coding sequence is copied in a process called transcription, producing an RNA copy of the gene's information

What volume of 0.220 M HBr solution (in mL) is required to obtain 0.060 moles of HBr?​

Answers

Answer:

273 mL.

Explanation:

From the question given above, the following data were obtained:

Molarity of HBr = 0.220 M

Mole of HBr = 0.060 mole

Volume =?

Molarity is simply defined as the mole of solute per unit litre of the solution. Mathematically, it is expressed as:

Molarity = mole /Volume

With the above formula, we can obtain the volume required as illustrated below:

Molarity of HBr = 0.220 M

Mole of HBr = 0.060 mole

Volume =?

Molarity = mole /Volume

0.220 = 0.060 / Volume

Cross multiply

0.220 × Volume = 0.060

Divide both side by 0.220

Volume = 0.060 / 0.220

Volume = 0.273 L

Finally, we shall convert 0.273 L to millilitres (mL). This can be obtained as follow:

1 L = 1000 mL

Therefore,

0.273 L = 0.273 L × 1000 mL / 1 L

0.273 L = 273 mL

Thus, 0.273 L is equivalent to 273 mL.

From the calculations made above, 273 mL of HBr is required.

The volume of 0.220 M HBr solution (in mL) required to obtain 0.060 moles of HBr is 272.7mL

From the question,

We are to determine the volume of 0.220M HBr solution that is required to obtain 0.060 moles of HBr.

To determine this, we will use the formula connecting number of moles, concentration and volume

From the formula,

Number of moles = Concentration × Volume

Then,

[tex]Volume = \frac{Number \ of \ moles}{Concentration}[/tex]

From the question,

Concentration of the HBr solution = 0.220 M

Required number of moles of HBr = 0.060 moles

∴ [tex]Volume \ of \ HBr \ required = \frac{0.060}{0.220}[/tex]

Volume of HBr required = 0.272727 L

Now, we will convert this to milliliter (mL)

(NOTE: 1L = 1000 mL)

∴ 0.272727 L = 0.272727 × 1000 mL

= 272.727 mL

272.7 mL

Hence, the volume of 0.220 M HBr solution (in mL) required to obtain 0.060 moles of HBr is 272.7mL

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How many aluminums are in the chemical formula of 2AI²(S0³)³?​

Answers

Answer:

4

General Formulas and Concepts:

Chemistry

Identifying Moles/Atoms and Compounds

Explanation:

Step 1: Define

Al₂(SO₃)₃ - Aluminum Sulfide

2Al₂(SO₃)₃

Step 2: Identify

In Aluminum Sulfide, we have 2 Al's for every 3 SO₃²⁻'s.

So far, we have 2 Al's in total.

BUT, since we have a 2 coefficient in 2Al₂(SO₃)₃, we need to multiply by 2.

Therefore, we have 4 Al's in total.

I need these done please

Answers

Answer:

A, it is metal oxide

A is metal oxide jdjdjdh

30) Which of the following two atoms are isotopes?

Answers

Answer:

The correct is the letter B

Please help me I need these answers

Answers

1 is true

2 is d 7

3 is

            1             e

            2             b

            3             d

            4             a

            5             c

Determine whether each observation describes a chemical or a physical property. 1. When a piece of sodium metal is placed in a test tube with water, the sodium zees and bubbles of gas are formed. 2. When table salt is added to water in a test tube, the table salt dissolves. . 3. When a glass marble is heated and then quickly cooled, it shatters. *​

Answers

1.Sodium metal reacts rapidly with water to form a colorless solution of sodium hydroxide ... strip is placed in a test tube containing 5 mL of hydrochloric acid, HCl. Both liquids ... If it fizzes and bubbles

2.When salt is mixed with water, the salt dissolves because the covalent bonds of water are stronger than the ionic bonds in the salt molecules.

3.When platinum is heated, then cooled to its original state, we say this is a physical change. 19. ... Scratches glass. Sour taste ... A bar of lead is more easily bent than is a bar of aluminum of the same size.

Which gas law is represented by the following equation: P1/T1 = P2/T2
O none of these
Avogadro's law
Charles's law
Gay-Lussac's law
Boyle's law

Answers

Answer:

none of these

Explanation:

The expression:

      P1/T1 = P2/T2 is a derivative of the combined gas law.

From the combination of the Boyle's and Charles's law, if the volume is taken to be constant, the pressure of the given mass of gas is directly proportional to the absolute temperature.

This is how the expression

      P1/T1 = P2/T2 was obtained.

Consider a copper-zinc corrosion couple. If the current density at the copper cathode is 0.05 A/cm2, calculate the weight loss of zinc per hour if the copper cathode area is 100 cm2 and the zinc anode area is 1 cm2 . Group of answer choices 0.061 g/h 6.1 g/h 61 g/h

Answers

Answer: the weight loss of zinc per hour is 6.1 g/h

Option c) 6.1 g/h is the correct answer.

Explanation:

Given that

copper cathode area is =  100 cm²

zinc anode area = 1 cm²

current density at the copper cathode = 0.05 A/cm²

The corrosion current can be converted to a rate of metal loss from its surface by using Faraday's law

W = ItM / nF

W is weight loss of metal , I is current ,

I = iCu × ACu = 0.05 A/cm² x 100 cm² = 5.0 A

M is atomic weight of metal

Atomic mass of Zn = 65.38 g/mol

n = number of electron

F = Faraday’s constant = 96,500 C/mol

so we substitute

W loss of Zn = (5 A) × (3600/h) (65.38 g/mol) / [2 × (96,500 C/mol) ]

= 1176840 / 193000

= 6.098 ≈ 6.1 g/h

Therefore the weight loss of zinc per hour is 6.1 g/h

Option c) 6.1 g/h is the correct answer.

HELP if water vapor condense on a cold surface is the initial and final energy thermal, phase, or chemical?

Answers

My answer to this great question would be thermal

why dont fish fly bcs they have tiny wings

Answers

Answer:

okay....

Explanation:

technically, fish do not have wings. they are called fins and they are used for the purpose of transportation, just as legs are for humans.

~Ren

they can’t fly because what they have aren’t even wings, they can swim underwater tho but not fly

Can someone explain how to do this?

Answers

Balanced equation :

3H₂+N₂⇒2NH₃

Further explanation

Equalization of chemical reaction equations can be done using variables. Steps in equalizing the reaction equation:

1. gives a coefficient on substances involved in the equation of reaction such as a, b, or c etc.

2. make an equation based on the similarity of the number of atoms where the number of atoms = coefficient × index between reactant and product

3. Select the coefficient of the substance with the most complex chemical formula equal to 1

Unbalanced⇒the number of atoms from both sides (reactants and products) is not the same

H₂+N₂⇒NH₃

H=2(left), H=3(right)

N=2(left), N=1(right)

Balanced ⇒ the number of atoms from both sides (reactants and products) is equal

3H₂+N₂⇒2NH₃

H=3x2=6(left), H=2x3=6(right)

N=2(left), N=2x1=2(right)

The law of conservation of mass can be demonstrated by a chemical reaction. Which of the
following models of a chemical reaction best represents the law of conservation of mass?

Answers

Answer : It’s C.

Cccccccccccccccccccccccccccccccccccccccc

The model of the chemical reaction that best represent the law of conservation of mass is the model with a balanced equation.

The correct answer to the question is the third option.

The law of conservation of matter states that matter can neither be created nor destroyed during a chemical reaction but can be transferred from one form to another.

The statement above, suggest that unbalanced equation simply means matter has been created or destroyed.

Therefore, the correct answer to the question given above will be the option in which the equation is balanced.

The option with a balanced equation is the third option.

See attachment photo.

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the mass of the empty graduated cylinder is 35.101 g. if 12.33 g of water is added to this cylinder, what is the total mass?

Answers

The total mass of the cylinder and the water is 47.431g.

How to calculate mass?

According to this question, the mass of an empty graduated cylinder is 35.101 g.

A graduated cylinder is known to be an item of glass laboratory equipment consisting of a tall, narrow cylinder with a scale, or graduations marked up its length, which is used to measure liquids and solutions fairly accurately, but not precisely.

If 12.33 g of water is added to this cylinder, the total mass of the cylinder and the water that was added can be calculated as follows:

Total mass = 12.33g (water) + 35.101g (empty cylinder) = 47.431g

Therefore, the total mass of the cylinder and the water is 47.431g.

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The stem and leaves of the plant in the diagram above are exhibiting which behavior?

Answers

Answer:

Try to go to quizzlet

Explanation:

Answer:

j

Explanation:

Part A
According to the following balanced reaction, how many moles of Ca(OH)2 will be formed from 4.33 moles of H₂O?

Answers

The number of moles of Ca(OH)2 formed is 4.33 moles.

Given,

number of moles of H₂O = 4.33

The balanced equation is :

CaO + H₂0 → Ca(OH)₂

From the balanced chemical reaction, we conclude that,

As 1 moles of H₂O  react with 1 mole of Ca(OH)₂

Then, 4.33 moles of H₂O will react with 4.33 moles of H₂O.

Thus, the number of moles of Ca(OH)₂ formed will be 4.33 moles.

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What is the anion in the chemical formula MnSe2?

Answers

Magnesium(IV)dioxide
Hope this helped

A 2.89 g sample of a metal chloride, MCl2, is dissolved in water and treated with excess aqueous silver nitrate. The silver chloride that formed weighed 6.41 g. Calculate the molar mass of M. Question 3 options: 70.9 g/mol 29 g/mol 58.0 g/mol 65 g/mol 72.4 g/mol

Answers

Answer:

58.0 g/mol

Explanation:

The reaction that takes place is:

MCl₂ + 2AgNO₃ → 2AgCl + M(NO₃)₂

First we calculate how many moles of silver chloride were produced, using its molar mass:

6.41 g AgCl ÷ 143.32 g/mol = 0.0447 mol AgCl

Then we convert AgCl moles into MCl₂ moles, using the stoichiometric ratio:

0.0447 mol AgCl * [tex]\frac{1molMCl_2}{2molAgCl}[/tex] = 0.0224 mol MCl₂

Now we calculate the molar mass of MCl₂, using the original mass of the sample:

2.86 g / 0.0224 mol = 127.68 g/mol

We can write the molar mass of MCl₂ as:

Molar Mass MCl₂ = Molar Mass of M + (Molar Mass of Cl)*2127.68 g/mol = Molar Mass of M + (35.45 g/mol)*2

Finally we calculate the molar mass of M:

Molar Mass of M = 57 g/mol

The closest option is 58.0 g/mol.

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