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solniwko [45]
3 years ago
12

The electron configuration of an element is 1s2 2s2. How many valence electrons does the element have?

Chemistry
1 answer:
faust18 [17]3 years ago
7 0

Answer:

Two valence electrons

Explanation:

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Describe the differences between bonding in an ionic compound and bonding in a covalent molecule.
Fudgin [204]

a covalent bond and an ionic bond. An ionic bond if formed from the transfer of electrons from the outer shell of atoms. ... An example of this is NaCl, where the sodium atom becomes Na+ due to the loss of electrons, and the chlorine atom becomes the negatively charged chloride (Cl-).

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3 years ago
ompare your TLC analysis with the results of the column chromatography. More polar molecules move more slowly through silica tha
Assoli18 [71]

Biphenyl will have a higher R value than the Methyl Orange.

Explanation:

Biphenyl is a aromatic hydrocarbon and it is a nonpolar molecule.

Methyl Orange is a organic compound with a -SO₃⁻Na⁺ polar functional group which will induce a high polarity in the compound.

You may find the chemical structures of both molecules in the attached picture.

Column chromatography, which use as stationary phase silica gel, is a good technique for separation of the Methyl Orange from Biphenyl.

Being a non-polar molecule,  Biphenyl will have a higher R value than the Methyl Orange.

To separate them you use a appropriate solvent as eluent, as exemple chloroform, and Biphenyl will elute first from the column and after that, as a separate phase, Methyl Orange will elute thus separating them.

Learn more about:

chromatography

brainly.com/question/10296715

#learnwithBrainly

7 0
3 years ago
Safety is a concern around electronic equipment of all types. What particular safety hazard may exist A. Laser light B. High vol
omeli [17]
All of the above. If you are going to narrow it down, it would be high voltage and radioactivity.
7 0
3 years ago
The solubility product of PbI2 is 7.9x10^-9. What is the molar solubility of PbI2 in distilled water?
Agata [3.3K]

<u>Answer:</u> The molar solubility of PbI_2 is 1.25\times 10^{-3}mol/L

<u>Explanation:</u>

Solubility is defined as the maximum amount of solute that can be dissolved in a solvent at equilibrium.

Solubility product is defined as the product of concentration of ions present in a solution each raised to the power its stoichiometric ratio.

The balanced equilibrium reaction for the ionization of calcium fluoride follows:

PbI_2\rightleftharpoons Pb^{2+}+2I^-

                s       2s

The expression for solubility constant for this reaction will be:

K_{sp}=[Pb^{2+}][I^-]^2

We are given:

K_{sp}=7.9\times 10^{-9}

Putting values in above equation, we get:

7.9\times 10^{-9}=(s)\times (2s)^2\\\\7.9\times 10^{-9}=4s^3\\\\s=1.25\times 10^{-3}mol/L

Hence, the molar solubility of PbI_2 is 1.25\times 10^{-3}mol/L

3 0
3 years ago
Rewrite 2000 to have 2 sig figs.
aliina [53]
20. Would be the right answer
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4 years ago
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