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malfutka [58]
3 years ago
14

Use the periodic table to answer the following question. What is the predicted order of first ionization energies from highest t

o lowest for beryllium, calcium, magnesium, and strontium? A. Be > Ca > Mg > Sr B. Be > Mg > Ca > Sr C. Ca > Sr > Be > Mg D. Sr > Ca > Mg > Be
Chemistry
2 answers:
emmainna [20.7K]3 years ago
7 0

Answer:

The order is determined as: Be > Mg > Ca > Sr (option B)

Explanation:

The electrons are attracted to the nucleus and it is necessary to provide energy to start them. The ionization energy I is then the energy needed to start an electron to a gaseous atom, isolated and in a fundamental state. The electrons of the last layer are always lost, which are the weakest attracted to the nucleus.

The elements beryllium, calcium, magnesium and strontium, if you place them in the periodic table, are in the same group. In the same group, the size of the atoms increases as they descend in the periodic table. In this way, electrons are found in layers increasingly distant from the nucleus, being less and less attracted to it. This facilitates its extraction from the atom. Finally, the ionization energy decreases as it descends in a group.  Following this criterion, the order is determined as: Be > Mg > Ca > Sr (option B)

Degger [83]3 years ago
6 0

B. Be > Mg > Ca > Sr

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Answer:

0.35 atm

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" At a certain temperature the vapor pressure of pure thiophene (C₄H₄S) is measured to be 0.60 atm. Suppose a solution is prepared by mixing 137. g of thiophene and 111. g of heptane (C₇H₁₆). Calculate the partial pressure of thiophene vapor above this solution. Be sure your answer has the correct number of significant digits. Note for advanced students: you may assume the solution is ideal."

Keep in mind that if the values in your question are different, your answer will be different too. <em>However the methodology will remain the same.</em>

First we <u>calculate the moles of thiophene and heptane</u>, using their molar mass:

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  • 111 g heptane ÷ 100 g/mol = 1.11 moles heptane

Total number of moles = 1.63 + 1.11 = 2.74 moles

The<u> mole fraction of thiophene</u> is:

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Partial pressure = Mole Fraction * Vapor pressure of Pure Thiophene

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san4es73 [151]

Answer:

-1

Explanation:

The relation between Kp and Kc is given below:

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Where,  

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R is gas constant

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For the first equilibrium reaction:

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<u>Δn = (2)-(2+1) = -1  </u>

Thus, Kp is:

K_p=  K_c\times (RT)^{-1}

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