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What is the wavelength of a photon with an energy of 3.50 x 10^-19 J ?

Leokris [45]

Answer:

λ = 5.68×10⁻⁷ m

Explanation:

Given data:

Energy of photon = 3.50 ×10⁻¹⁹ J

Wavelength of photon = ?

Solution:

E = hc/λ

h = planck's constant = 6.63×10⁻³⁴ Js

c = 3×10⁸ m/s

Now we will put the values in formula.

3.50 ×10⁻¹⁹ J = 6.63×10⁻³⁴ Js × 3×10⁸ m/s/ λ

λ = 6.63×10⁻³⁴ Js × 3×10⁸ m/s / 3.50 ×10⁻¹⁹ J

λ = 19.89×10⁻²⁶ J.m / 3.50 ×10⁻¹⁹ J

λ = 5.68×10⁻⁷ m

8 0

3 years ago

A solution is made by mixing 33.0 ml of ethanol, C2H6O and 67.0 ml of water. Assuming ideal behavior, what is the vapor pressure

ivann1987 [24]

Grams ethanol = 33 ml times .789 gms/ml = 26.037 gms

Moles ethanol = 26.037 gms / 46 gms/mole = .57 moles 

Moles water = 67 ml or 67 grams/18 gms/mole = 3.22 moles 

total moles = .57 + 3.72 = 4.29 moles 

Mole fraction ethanol = .57 moles ethanol / 4.29 moles total = 0.13

Moles fraction water = 3.72 moles water / 4.29 moles total = 0.87

Partial pressure of ethanol = mole fraction ethanol (.13) _ times VP ethanol 43.9 torr) = 5.707 torr 

partial pressure water = mole fraction water .87) times VP water (l7.5 torr) = 15.23 torr 

Total vapor pressure over solution = 5.71 torr + 15.23 torr = 20.94 torr

7 0

3 years ago

The buffer solution is used to control the pH to insure that it does not become too high because excessively basic solutions cou

oksian1 [2.3K]

Answer:

pH = 12.7

Explanation:

First, we have to calculate the [Ca²⁺] in a solution of about 250 ppm CaCO₃.

$\frac{250mgCaCO_{3}}{L} .\frac{1gCaCO_{3}}{1000mgCaCO_{3}} .\frac{1molCa^{2+} }{100gCaCO_{3}} =2.5 \times 10^{-3} M$

Now, let's consider the dissolution of Ca(OH)₂ in water.

Ca(OH)₂(s) ⇄ Ca²⁺(aq) + 2 OH⁻(aq)

The solubility product Ksp is:

Ksp = [Ca²⁺] × [OH⁻]²

[OH⁻] = √(Ksp/[Ca²⁺]) = √(6.5 × 10⁻⁶/2.5 × 10⁻³) = 5.1 × 10⁻² M

Finally, we can calculate pOH and pH.

pOH = -log [OH⁻] = -log (5.1 × 10⁻²) = 1.3

pH + pOH = 14 ⇒ pH = 14 - pOH = 14 - 1.3 = 12.7

5 0

3 years ago

Share what you have learned about first aid to your family...... please help me with this.

Anon25 [30]

Answer:

$\huge\pink{ \mid{ \underline{ \overline{ \tt Answer :- }} \mid}}$

=> First Aid enables you to assist persons who become injured in the event of an accident or emergency situation until help arrives.

$\huge\blue{ \mid{ \underline{ \overline{ \tt Situations :- }} \mid}}$

=> If an accident happens in the workplace, in your home or in a public space, you can use the help of a first aid kit.

=> In situations such as when someone ingests a harmful substance, suffers from a heart attack, a seizure or stroke, is involved in a motor vehicle accident or is caught in a natural disaster, a person trained and knowledgeable in even the very basics of First Aid can be of extreme importance in assisting the injured person(s) until emergency responders arrive.

7 0

3 years ago

At night, low temperatures can cause rocks to: melt contract expand

vampirchik [111]

At night, low temperatures can cause rocks to CONTRACT.

3 0

3 years ago

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