All categories

2 years ago

X-ray photons with a wavelength of 0.135 nm . express the energy numerically in kilojoules per mole.

Chemistry

2 answers:

Novay_Z [31]2 years ago

8 0

Answer:

884.9×10^3 KJ mol-1

Explanation:

From E= hf

E= Energy of the photon

h= Plank's constant

f= frequency of the radiation

But f= c/λ

c= speed of light

λ= wavelength

Hence

E= hc/λ

E= 6.63×10^-34 × 3×10^8/135×10^-12

E= 147×10^-17 × 6.02×10^23

E= 884.9×10^3 KJ mol-1

STALIN [3.7K]2 years ago

7 0

Using E=hν where h is Planck's constant and v is the frequency of the photon. In the question above,the wavelenght is given so we can find the frequency of the photon using c=λν. c is a constant =3*10^8 so frequency is equal to
(3*10^8)/0.135*10^-9. Then use ur frequency in the eqn above using h 6.626*10^-34

You might be interested in

If a 0.4856 gram sample of khp is dissolved in sufficient water to prepare 250 ml of solution, and 25 ml of the solution require

dangina [55]

Mass of potassium hydrogen pthalate KHP is 0.4856 g, its molar mass is 204.22 g/mol, number of moles of KHP can be calculated as follows:

$n=\frac{m}{M}$

Here, m is mass and M is molar mass, putting the values,

$n=\frac{0.4856 g}{204.22 g/mol}=0.00237 mol$

This will be number of moles of NaOH at equivalent point.

Detailed calculations:

Molarity is defined as number of moles in 1 L of solution, for 250 mL of solution, molarity will be:

$M=\frac{0.00237 mol}{250 \times 10^{-3}L}=0.009511 M$

For 25 mL, apply dilution law as follows:

$M_{1}V_{1}=M_{2}V_{2}$

Putting the values,

$0.009511\times 250=M_{2}\times 25 mL$

On rearranging,

$M_{2}=\frac{0.009511\times 250}{25}=0.09511 M$

Convert molarity into number of moles,

$n=M\times V=0.09511 mol/L\times 25\times 10^{-3}L=0.00237 mol$

At equivalent point, number of moles of KHP will be equal to NaOH, thus, number of moles of NaOH will be 0.00237 mol.

Calculation for molarity:

Volume of NaOH is 18.75 mL, thus, molarity can be calculated as follows:

$M=\frac{n}{V}$

Putting the values,

$M=\frac{0.00237 mol}{18.75\times 10^{-3}L}=0.1264 M$

Therefore, molarity of NaOH is 0.1264 M

7 0

2 years ago

A curium-245 nucleus is hit with a neutron and changes as shown by the equation. Complete the equation by filling in the missing

Lera25 [3.4K]

Try this option:

$^{245}_{96}Cm+^1_0n=^{103}_{42}Mo+^{245+1-103-3*1}_{96+0-42-3*0}(X)+3^1_0n;$

$^{245}_{96}Cm+^1_0n=> ^{103}_{42}Mo+^{140}_{54}(X)+3^1_0n;$

$^{245}_{96}Cm+^1_0n=> ^{103}_{42}Mo+^{140}_{54}Xe+3^1_0n;$

Answer:

$^{140}_{54}Xe$

8 0

2 years ago

Read 2 more answers

Pesticide concentrations in the Rhine River between Germany and France between 1969 and 1975 averaged 0.55 mg/L of hexachloroben

sertanlavr [38]

Answer:

1.93×10⁻³ mmoles/L of C₆Cl₆; 1.58×10⁻⁴ mmoles/L of C₁₂H₈Cl₆O; 3.51×10⁻³ mmoles/L of C₆H₆Cl₆

Explanation:

We have to find out the molar mass of each pesticide to calculate the moles, and then the milimoles

C₆Cl₆ → 12. 6 + 35.45 .6 = 284.7 g/m

C₁₂H₈Cl₆O → 12 . 12 + 8.1 + 35.45 .6 + 16 = 380.7 g/m

C₆H₆Cl₆ → 12.6 + 6.1 + 35.45 .6 = 290,7 g/m

Let's convert mg to g (/1000)

0.55 mg / 1000 = 5.5×10⁻⁴ g

0.060 mg / 1000 = 6×10⁻⁵ g

1.02 mg / 1000 = 1.02×10⁻³ g

Now we can know the moles (mass / molar mass)

5.5×10⁻⁴ g / 284.7 g/m = 1.93×10⁻⁶ moles of C₆Cl₆

6×10⁻⁵ g / 380.7 g/m = 1.58×10⁻⁷ moles of C₁₂H₈Cl₆O

1.02×10⁻³ g / 290,7 g/m = 3.51×10⁻⁶ moles of C₆H₆Cl₆

Milimoles = Mol . 1000

1.93×10⁻⁶ . 1000 = 1.93×10⁻³ mmoles of C₆Cl₆

1.58×10⁻⁷ . 1000 = 1.58×10⁻⁴ mmoles of C₁₂H₈Cl₆O

3.51×10⁻⁶ . 1000 = 3.51×10⁻³ mmoles of C₆H₆Cl₆

6 0

2 years ago

The table lists the chemical formulas or symbols of a few common substances. Which two substances are compounds? A) aluminum and

katrin [286]

D is the correct answer

every other option contains an element

7 0

2 years ago

Read 2 more answers

The reaction of 0.779 g K with O2 forms 1.417 g potassium superoxide, a substance used in self-contained breathing devices. Dete

zhannawk [14.2K]

First we need to find the number of moles of both K and O reacted
K - 0.779 g / 39 g/mol
= 0.02 mol
the mass of O₂ reacted = 1.417 g - 0.779 g = 0.638 g
O₂ moles = 0.638 g / 32 g/mol
= 0.02 mol
the number of both K and O₂ moles reacted are equal
therefore stoichiometry of K to O₂ reacted are 1:1
then the formula of potassium superoxide is KO₂

3 0

2 years ago