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3 years ago

A student submits the following work on the mass number, but he has made a few mistakes. Select all of his mistakes.

Chemistry

2 answers:

MatroZZZ [7]3 years ago

8 0

Answer:

1. Calculating the mass number for an atom requires that we know the atomic number and the number of protons in the atom's nucleus.

2. The mass number then gives us the average weight of atoms of a given element.

3. However, as long as the number of protons equals the number of neutrons, the values balance out and we always obtain a whole number for the mass number.

Explanation:

MatroZZZ [7]3 years ago

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A binding protein binds to a ligand L with a Kd of 400 nM. What is the concentration of ligand when Y is (a) 0.25, (b) 0.6, (c)

Mrac [35]

Answer:

(a) 133.33nm

(b) 600nm

Explanation:

The concentration of Y can be determined by using the formula:

$Y = \dfrac{[L]}{k_d+[L]}$

where;

[L] = concentration of the binding ligand.

kd = 400 nm

Thus:

When Y = 0.25; we get :

$0.25 = \dfrac{[L]}{400+[L]}$

0.25 (400 + [L]) = [L]

100 + 0.25[L] = [L]

100 = [L] - 0.25 [L]

100 = 0.75 [L]

[L] = 100/0.75

[L] = 133.33 nm

At, Y = 0.6

$0.6 = \dfrac{[L]}{400+[L]}$

0.6 (400 + [L]) = [L]

240 + 0.6[L] = [L]

240 = [L] - 0.6 [L]

240 = 0.4 [L]

[L] = 240/0.4

[L] = 600 nm

At, Y = 0.95

$0.95 = \dfrac{[L]}{400+[L]}$

0.95 (400 + [L]) = [L]

380 + 0.95[L] = [L]

380 = [L] - 0.95 [L]

380 = 0.05 [L]

[L] = 380/0.05

[L] = 7600 nm

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3 years ago

Critical practices to control the amount of solid waste include __________.

erica [24]

Reduce, reuse, recycle, compost. I think hope its helpful.

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3 years ago

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1. Write the complete electron configuration for each atom on the blank line. Lithium Fluorine Carbon Argon Sulfur Nickel Rubidi

suter [353]

Answer:

Explanation:

Answer 1:

Lithium : 1s2 2s1 Fluorine: 1s2 2s2 2p5 Carbon: 1s2 2s2 2p2

Argon : 1s2 2s2 2p6 3s2 3p6 Sulphur: 1s2 2s2 2p6 3s2 3p4

Nickel: 1s2 2s2 2p6 3s2 3p6 3d8 4s2 Rubidium: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 5s1 Xenon: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6

Answer 2: A. Fluorine B. Calcium

C. It is Tellurium if this was the exact electronic configuration 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p4 you intend to write, if not, no element has such electonic configuration.

D. Bromine but the correct electronic configuration is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p5

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3 years ago

Onsider the following reaction at equilibrium:

11111nata11111 [884]

Explanation:

Any change in the equilibrium is studied on the basis of Le-Chatelier's principle.

This principle states that if there is any change in the variables of the reaction, the equilibrium will shift in the direction to minimize the effect.

For the given equation:

$C(s)+H_2O(l)\leftrightharpoons CO(g)+H_2(g)$

A. C is added to the reaction mixture.

If the concentration of reactant specie is increased , according to the Le-Chatlier's principle , the equilibrium will shift in the direction where decrease in concentration of reactant specie occurs. So, on increasing C ,equilibrium will shift in right direction.

B. $H_2O$ is condensed and removed from the reaction mixture.

If the concentration of reactant specie is decreased , according to the Le-Chatlier's principle , the equilibrium will shift in the direction where increase in concentration of reactant specie occurs. So, on removing water vapor ,the equilibrium will shift in left direction.

C. CO is added to the reaction mixture.

If the concentration of product specie is increased , according to the Le-Chatlier's principle , the equilibrium will shift in the direction where decrease in concentration of product specie occurs. So, on increasing CO, the equilibrium will shift in left direction.

D. $H_2$ is removed from the reaction mixture.

If the concentration of product specie is decreased , according to the Le-Chatlier's principle , the equilibrium will shift in the direction where increase in concentration of product specie occurs. So, on removing hydrogen , the equilibrium will shift in right direction.

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3 years ago

A gas mixture containing oxygen, nitrogen, and carbon dioxide has a total pressure of 42.9 kPa. What is the partial pressure of

Lady bird [3.3K]

The total Pressure equals the sum of all pressures contained

Since total pressure and the pressure of nitrogen and oxygen is given, finding the pressure of carbon dioxide is given by: 

Pressure of Carbon dioxide = 42.9- 6.6- 23.0 
=13.3kPa

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3 years ago

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