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What is the freezing point of a solution of 7.15 g MgCl2 in 100 g of water? K f for water is 1.86°C/m. What is the freezing point of a solution of 7.15 g MgCl2 in 100 g of water? K f for water is 1.86°C/m. -0.140°C -2.80°C -1.40°C -4.18°C

Answers

Answer 1

Answer:

Answer:

THE NEW FREEZING POINT IS -4.196 °C

Explanation:

ΔTf = 1 Kf m

molarity of MgCl2:

Molar mass = (24 + 35.5 *2) g/mol

molar mass = 95 g/mol

7.15 g of MgCl2 in 100 g of water

7.15 g = 100 g

(7.15 * 100 / 1000) = 1000 g or 1 L or 1 dm3

= 0.715 g /dm3

Molarity in mol/dm3 = molarity in g/dm3 / molar mass

= 0.715 g /dm3 / 95 g/mol

m = 0.00752 mol/ dm3

So therefore:

ΔTf = i Kf m

1 = 3 (1 Mg and 2 Cl)

Kf = 1.86 °C/m

M = 0.752 moles

So we have:

ΔTf = 3 * 1.86 * 0.752

ΔTf = 4.196 °C

The new freezing point therefore will be 0 °C - 4.196 °C which is equals to - 4.196 °C

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Determine the end (final) value of n in a hydrogen atom transition, if the electron starts in and the atom emits a photon of light with a wavelength of 486 nm. Group of answer choices

Answers

Complete Question

Determine the end (final) value of n in a hydrogen atom transition, if the electron starts in n=4 and the atom emits a photon of light with a wavelength of 486 nm. Group of answer choices

Answer:

$n=2$

Explanation:

From the question we are told that:

Wavelength $\lambda=486nm=>486*10^(-9)$

Generally the equation for Atom Transition is mathematically given by

$(1)/(\lambda)=R_(\infty )((1)/(n_1^2)-(1)/(n_2^2))$

Where

Rydberg constant $R_(\infty)=1.097*10^7$

Therefore

$(1)/(486*10^(-9))=1.097*10^7*((1)/(n_1^2)-(1)/(4^2))$

$((1)/(n_1^2)-(1)/(4^2))=(1)/(486*10^(-9)*1.097*10^7)$

$n_1^2=3.98$

$n=1.99$

$n=2$

Final answer:

The final value of n in the hydrogen atom transition is 4.

Explanation:

The end value of n in a hydrogen atom transition can be determined using the equation En = Eo * Z^2 / n^2, where En is the energy of the excited state and Eo is the ionization energy. Since the electron starts in the ground state (n = 1) and emits a photon of light with a wavelength of 486 nm, we can use Equation 6.49 to solve for n. By substituting m = 1 and λ = 486 nm into Equation 6.49, we find that n is approximately 4. Therefore, the final value of n in the hydrogen atom transition is 4.

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What else is produced during the replacement reaction of silver nitrate and potassium sulfate? 2AgNO3 + K2SO4 Ag2SO4 + ________

Answers

Answer:

Explanation:

Answer:

Explanation:

Please ignore my answers because they are wrong.

Answers

Answer:

The wavelength of the radio wave is 3.003 m.

The energy of the radio wave is $6.6194* 10^(-26) J$ .

Explanation:

Frequency of the radio waves, ν = 99.9 MHz = $99.9* 10^6 Hz$

Wavelength and frequency are related to each other by realtion:

$\lambda =(c)/(\nu )$

$\lambda$ = Wavelength of the wave

c = speed of the light

ν = Frequency of the wave

$\lambda =(3* 10^8 m/s)/(99.9* 10^6 s^(-1))=3.003 m$

The wavelength of the radio wave is 3.003 m.

The energy of the electromagnetic wave is given by Planck's equation:

$E=h* \nu$

h = Planck's constant = $6.626* 10^(-34) Js$

The energy of the radio wave with 99.9 MHz frequency will be:

$E=6.626* 10^(-34) Js* 99.9* 10^6 s^(-1)$

$E = 6.6194* 10^(-26) J$

The energy of the radio wave is $6.6194* 10^(-26) J$ .

To what extend must a soln conc 40mg 4g NO3 pa cm3 be dilute to yield one of conc 16mg 4g NO3 pa cm3

Answers

Each ml should be dilute to 2.5 ml

To each ml of solution 1.5 ml of water should be added

An organic compound was extracted into dichloromethane and then the aqueous layer is shaken with saturated sodium chloride solution. What is the purpose of the sodium chloride? A. to decrease the solubility of the organic product in water B. to raise the density of the aqueous layer so that it will be the bottom layer C. to lower the boiling point of the water to cause the water D. to be immiscible with the methylene chloride

Answers

Answer: option A. to decrease the solubility of the organic product in water

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Please help 25 points :DPhases of Matter Activity
Now it is your turn to show what you know about phases of matter and thermal energy transfer! Your task is to create a presentation to explain the transformation of a substance as it changes phases. You may choose to write a story or create a comic strip. For your story or comic, you will create a main character and detail the adventure as your character is exposed to thermal energy, causing it to undergo phase changes from a solid, to a liquid, to a gas. You may create your own comic strip using drawings, presentation software, or this comic strip template.
Your presentation must include the following:
title and introduction of your character, including what substance the character is made of
source of thermal energy your character encountered (conduction, convection, and/or radiation)
a detailed description and/or diagram of the particle transformation from solid to liquid phase
a detailed description and/or diagram of the particle transformation from liquid to the gas phase
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Answers

Here is a comic strip created to explain the transformation of a substance as it changes phases.

How to make a comic strip?

Title: The Adventures of Mr. Ice Cube

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