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4 years ago

Selenium has six valence electrons. What is the valence of selenium?

1 answer:

3 0

The six electrons in the outermost shell allow selenium to have a variety of valence numbers.

The valence of selenium depends on which compound it is in. Selenium is very similar to sulfur. It may have a valence of 6.
EXAMPLE:

selenium hexafluoride SeF6, selenium trioxide SeO3

May have 4;

example

selenium tetrafluoride SeF4, selenium dioxide SeO2

MAy have 2;

example

selenium difluoride SeF2, selenium dichloride SeCl2

and may have -2;

example

hydrogen selenide H2Se

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Explain in terms of particles in the atoms of an element why statement c is false?

const2013 [10]

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3 years ago

Using the equation pH = -log [H+], determine the pH of a solution with a hydrogen ion concentration, or [H+], of 1x10-5. HINT: l

kipiarov [429]

Answer:

the answer is pH of 7 I don't no Hydrochloric hijinx work

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3 years ago

Calculate the density in g/l of co2 gas at 27 Celsius and 0.500 atm pressure

lesya692 [45]

Answer:

The density of CO₂ gas at 27 Celsius and 0.500 atm is 0.89 $\frac{grams}{L}$

Explanation:

An ideal gas is a theoretical gas that is considered to be composed of randomly moving point particles that do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.

The pressure, P, the temperature, T, and the volume, V, of an ideal gas, are related by a simple formula called the ideal gas law:

P*V = n*R*T Equation (A)

where P is the gas pressure, V is the volume that occupies, T is its temperature, R is the ideal gas constant, and n is the number of moles of the gas.

Density allows you to measure the amount of mass in a given volume of a substance. So density is defined as the quotient between the mass of a body and the volume it occupies:

$density=\frac{mass}{volume}$

Being the molar mass of a substance the mass contained in one mole of said substance, the number of moles can be expressed as:

$n=\frac{mass}{molar mass}$ Equation (B)

Replacing in Equation (A):

P*V= $\frac{mass}{molar mass}$ *R*T

Solving to get the definition of density expressed in the equation, you get:

$density=\frac{mass}{V} =\frac{P*molar mass}{R*T}$

Being:

P=0.500 atm
Molar mass CO₂= 44 g/mole

R= 0.082 $\frac{atm*L}{mole*K}$

T= 27 C= 300 K (being 0 C=273 K)

and replacing:

$density=\frac{mass}{V} =\frac{0.500 atm*44 \frac{g}{mole} }{0.082 \frac{atm*L}{mole*K} *300 K}$

you get:

density= 0.89 $\frac{grams}{L}$

The density of CO₂ gas at 27 Celsius and 0.500 atm is 0.89 $\frac{grams}{L}$

3 0

4 years ago

The reaction 2 a → b c has a kc of 0.2. the reaction is commenced with initial concentrations [a] = 0.2 m, [b] = 0.2 m and [c] =

LuckyWell [14K]

Kc = [b]*[c]/([a]^2) = (0.2 M)^2/(0.2 M)^2 = 1.0
To achieve equilibrium, Kc must be equal to 0.2, therefore Kc must decrease, so the concentrations of b and c must decrease and the concentration of a must increase, meaning the reaction will proceed toward the formation of a.

7 0

3 years ago

Balance the equation for this reaction in an acidic solution MnO-4 to NO-3+Mn+2

marin [14]

Answer

MnO₄ + 2H⁺ +3NO₂⁻ →3NO₃⁻ + Mn²⁺ +H₂O

Explanation

This is a redox reaction (oxidation-reduction reaction) which involves the transfer of electrons between two species. i.e

Mn + 6e⁻→Mn²⁺ (reduction)

3N³⁺- 6e⁻→3Mn⁵⁺(oxidation)

4 0

4 years ago

Read 2 more answers