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A solution contains 0.10 M Pb2+ and 0.10 M Cu2.. Which cation will precipitate first when a solution of NazS is slowly added to the mixture? Refer to the information sheet for solubility constants. P A) Pb2+ B) Cu2+ C) impossible to tell D) both cations

Answers

Answer 1

Answer:

Answer:

b) Cu2+

Explanation:

information sheet for solubility constants:

Ksp PbS = 3.4 E-28

Ksp CuS = 6.0 E-37

PbS ↔ Pb2+ + S2-

∴ Ksp = 3.4 E-28 = [ Pb2+ ] * [ S2- ]

∴ [ Pb2+ ] = 0.10 M

⇒ [ S2- ] = 3.4 E-28 / 0.10 = 3.4 E-27 M

CuS ↔ Cu2+ + S2-

∴ Ksp = 6.0 E-37 = [ Cu2+ ] * [ S2- ]

∴ [ Cu2+ ] = 0.10 M

⇒ [ S2- ] = 6.0 E-37 / 0.10 = 6.0 E-36 M

we have:

(1) [ S2- ] PbS >> [ S2- ] CuS

(2) Ksp PbS >> Ksp CuS

from (1) and (2) it can determined, that separation can be carried out and also the cation that precipitates first is the Cu2+

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What is the daughter nucleus produced when 63 Zn undergoes electron capture? Replace each question mark with the appropriate integer or symbol.

Answers

Answer: The daughter nuclei is $_(29)^(63)\textrm{Cu}$

Explanation:

Electron capture is defined as the process in which an electron is drawn to the nucleus where it combines with a proton to form a neutron and a neutrino particle.

$_Z^A\textrm{X}+e^-\rightarrow _(Z-1)^A\textrm{Y}+\gamma e$

The chemical equation for the reaction of electron capture of Zinc-63 nucleus follows:

$_(30)^(63)\textrm{Zn}+e^-\rightarrow _(29)^(63)\textrm{Cu}+\gamma e$

The parent nuclei in the above reaction is Zinc-63 and the daughter nuclei produced in the above reaction is copper-63 nucleus.

Hence, the daughter nuclei is $_(29)^(63)\textrm{Cu}$

Final answer:

When Zinc-63 undergoes electron capture, it results in the creation of a Copper-63 daughter nucleus. This is due to the atomic number decreasing by one (from 30 to 29) during electron capture, but the mass number remaining unchanged.

Explanation:

Electron capture is a process where a proton-rich nucleus absorbs an inner shell electron, which results in a conversion of a proton into a neutron, and the emission of an electron neutrino. In doing so, the atomic number decreases by one, while the mass number stays the same. Therefore, in the case of 63 Zn (zinc-63), the atomic number is 30 prior to electron capture. After electron capture, the atomic number will decrease by one to become 29, leading to the production of 63 Cu (copper-63).

Remember that the atomic number (bottom number), also known as the proton number, determines the element. Therefore, in our example, Zn changes to Cu. The fact that the mass number (top number) remains the same is due to the total number of protons and neutrons (nucleons) being conserved.

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A 15.0 g piece of copper wire is heated, and the temperature of the wire changes from 12.0oC to 79.0oC. The amount of heat absorbed is 775 cal. What is the specific heat of copper?

Answers

Answer:

The specific heat of the copper is 0.771 cal/ grams °C

Explanation:

Step 1: Data given

Mass of the piece of copper = 15.0 grams

The temperature of the wire changes from 12.0 °C to 79.0 °C

The amount of heat absorbed is 775 cal

Step 2: Calculate the specific heat of copper

Q = m*c*ΔT

⇒with Q = the heat absorbed = 775 cal

⇒with m = the mass of the copper = 15.0 grams

⇒with c = the specific heat of copper = TO BE DETERMINED

⇒with ΔT = The change in temperature = 79.0 °C - 12.0 °C = 67.0 °C

775 cal = 15.0 grams * c * 67.0 °C

c = 0.771 cal/gm °C

The specific heat of the copper is 0.771 cal/ grams °C

James adds some magnetic marbles to a glass jar full of ordinary marbles, and then shakes up the jar.

Answers

Answer: Magnetic marbles will tend to attract each other

A gas has a volume of 300 mL and a pressure of 2 atm. What volume will the gas occupy when the pressure isincreased to 7 atm (total)?

Answers

Answer:

The answer is 85.71 mL

Explanation:

The new volume can be found by using the formula for Boyle's law which is

$P_1V_1 = P_2V_2$

where

P1 is the initial pressure

P2 is the final pressure

V1 is the initial volume

V2 is the final volume

Since we are finding the new volume

$V_2 = (P_1V_1)/(P_2) \n$

We have

$V_2 = (300 * 2)/(7) = (600)/(7) \n = 85.714285...$

We have the final answer as

85.71 mL

Hope this helps you

The resolution calculated for the tlc separation of a two-component mixture is determined to be equal to 2.0. does the represent good separation or not? explain

Answers

Answer: No, it does not represent a good separation.

Explanation: Resolution is the measure of extent of separation between two components and the base-line separation. It is calculated using the formula

$R_s=2* ((Rt_1-Rt_2))/((W_1+W_2))$

Where, $R_s$ = resolution

$(Rt_1-Rt_2)$ = Difference between the retention times of two components.

$W_1+W_2$ = Spot widths of two components.

The perfect resolution is considered as 100.

Here, we are given that the two components in a mixture both have a resolution at 2.0 that means both the peaks are overlapping each other and thus the components cannot be determined accurately.

Thus, this does not represent a good separation as as the two components are spotted closely.

Final answer:

A resolution of 2.0 in TLC separation indicates good separation, as values of 1.0 or higher are generally acceptable. It demonstrates that the mixture's components have been well resolved on the chromatogram, and each component can be distinctly identified.

Explanation:

A resolution of 2.0 in TLC separation indicates good separation of a two-component mixture. In chromatography, resolution measures how well two components in a mixture are separated based on their differences in migration rates on the chromatogram. A resolution value of 1.0 or above is generally acceptable, with higher values indicating better separation. In your case, a resolution of 2.0 suggests that the two components have been well resolved, with each peak being distinctly separated from the other, allowing for easier identification and quantification.

Additionally, the effectiveness of separation can often be improved by repeating the separation process. This iterative approach is based on the Le Chatelier's principle, which involves upsetting the phase distribution equilibrium to achieve a higher purity product. Such methods are also touched upon when discussing column chromatography and repetitive extraction protocols in automated systems.

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g For a given arrangement of ions, the lattice energy increases as ionic radius ________ and as ionic charge ________.

Answers

For a given arrangement of ions, the lattice energy increases as ionic radius decreases and as ionic charge increases.

What is ion?

An atom or molecule is said to be an ion if one or more of whose valence electrons have been acquired or lost, providing it a net negative or positive electrical charge.

Faraday knew that metals disintegrated together into solution place at a single electrode and that a second metal was placed first from solution at the opposite electrode, as such matter had to be trying to move underneath the impact of an electrical current even though he was unable to identify the particles trying to move between the electrodes. For a given arrangement of ions, the lattice energy increases as ionic radius decreases and as ionic charge increases.

Therefore, for a given arrangement of ions, the lattice energy increases as ionic radius decreases and as ionic charge increases.

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Answer:

as the charge of the ions increases, the lattice energy increases. as the size of the ions increases, the lattice energy decreases.

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