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3 years ago

8

Which set of elements has 4 valence electrons?

1 answer:

pickupchik [31]3 years ago

4 0

Answer:

carbon group

All the carbon group atoms, having four valence electrons, form covalent bonds with nonmetal atoms; carbon and silicon cannot lose or gain electrons to form free ions, whereas germanium, tin, and lead do form metallic ions but only with two positive charges.

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Give the formula of a reagent which will form a

Sloan [31]

Answer:

The group reagent is H2S in the presence of NH4Cl .

Explanation:

Mn is fourth group radical in qualitative analysis ;

the group reagent is H2S in the presence of NH4Cl .

then Mn precipitates as buff coloured sulphide , which is soluble in HCl .

MnS + 2HCl ---------> MnCl2 + H2S

on heating the solution with NaOH with bromine water, manganesedioxide gets precipitated.

MnCl2 + 2NaOH --------> Mn(OH)2 + 2NaCl

Mn(OH)2 + O -------> MnO2 + H2O

whereas NiS is insoluble in HCl. the nickel chloride gives a scarlet red precipitate with dimethy gly oxime.

5 0

3 years ago

What happens to a solution when you add an acid to

Airida [17]

Toooooooooooooo whatttttt?????

7 0

3 years ago

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Calculate the osmotic pressure of 5.0g of sucrose ssolution in 1L. Answer should be in Torr

Pani-rosa [81]

Answer: The osmotic pressure of 5.0g of sucrose solution in 1 L is 271.32 torr.

Explanation:

Given: Mass = 5.0 g

Volume = 1 L

Molar mass of sucrose = 342.3 g/mol

Moles are the mass of a substance divided by its molar mass. So, moles of sucrose are calculated as follows.

$Moles = \frac{mass}{molarmass}\\= \frac{5.0 g}{342.3 g/mol}\\= 0.0146 mol$

Hence, concentration of sucrose is calculated as follows.

$Concentration = \frac{moles}{Volume (in L)}\\= \frac{0.0146 mol}{1 L}\\= 0.0146 M$

Formula used to calculate osmotic pressure is as follows.

$\pi = CRT$

where,

$\pi$ = osmotic pressure

C = concentration

R = gas constant = 0.0821 L atm/mol K

T = temperature

Substitute the values into above formula as follows.

$\pi = CRT\\= 0.0146 \times 0.0821 L atm/mol K \times 298 K\\= 0.357 atm (1 atm = 760 torr)\\= 271.32 torr$

Thus, we can conclude that the osmotic pressure of 5.0g of sucrose solution in 1 L is 271.32 torr.

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3 years ago

Which is the main source of dissolved oxegyn in the ocean

kolezko [41]

Answer:phytoplankton

Explanation:

6 0

3 years ago

Which part of the mantle is still a solid but flows thick , heavy liquid? A.asthensosphere B.crust C.core D.lithosphere

enot [183]

I think its, A because its below the lithosphere and the lithosphere it between the crust and mantel. no liquids there.

4 0

3 years ago

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