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3 years ago

What is the valence number of an element that has 3 electron in its outermost shell?

1 answer:

5 0

Lithium has 3 electrons --- 2 in the first shell, and 1 in the second shell (so one valence electron). Beryllim has 4 electrons --- 2 in the first shell, and 2 in the second shell (so two valence electrons). Boron has 5 electrons --- 2 in the first shell, and 3 in the second shell (so three valence electrons).Jul 27, 2019
Hope that helps and may I get brainliest?

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Based on the standard free energies of formation, which of the following reactions represent a feasible way to synthesize the pr

yuradex [85]

Explanation:

According the equation of Gibb's free energy -

∆G = ∆H -T∆S

∆G = is the change in gibb's free energy

∆H = is the change in enthalpy

T = temperature

∆S = is the change in entropy .

And , the sign of the ΔG , determines whether the reaction is Spontaneous or non Spontaneous or at equilibrium ,

i.e. ,

• ΔG < 0 , the reaction is Spontaneous

• ΔG > 0 , the reaction is non Spontaneous

• ΔG = 0 , the reaction is at equilibrium

N₂(g) + H₂(g) → N₂H₄ (g) ; ΔG⁰f = 159.3 kJ/mol

ΔG > 0 , the reaction is non Spontaneous , the reaction is not feasible in the forward direction

2Na(s) + O₂(g) → Na₂O₂ (s) ; ΔG⁰ f = − 447.7kJ/mol

ΔG < 0 , the reaction is Spontaneous , the reaction is feasible in the forward direction .

C(s) + 2S(s) → CS₂ (g) ; ΔG⁰f = 67.1 kJ/mol

ΔG > 0 , the reaction is non Spontaneous , the reaction is not feasible in the forward direction

Ca(s) + 12 O₂ (g) → CaO (s) ; ΔG⁰f = −604.0 kJ/mol

ΔG < 0 , the reaction is Spontaneous , the reaction is feasible in the forward direction .

8 0

3 years ago

Help please lol I’m stuggling

Mazyrski [523]

Answer:

balenced

Explanation:

6 0

3 years ago

Write the half-reactions as they occur at each electrode and the net cell reaction for this electrochemical cell containing indi

AlexFokin [52]

Explanation:

The given cell reaction is as follows.

$In(s)| In^{3+}(aq) || Cd^{2+}(aq) | Cd(s)$

Hence, reactions taking place at the cathode and anode are as follows.

At anode ; Oxidation-half reaction : $In(s) \rightarrow In^{3+}(aq) + 3e^{-}$ ...... (1)

At cathode; Reduction-half reaction : $Cd^{2+}(aq) + 2e^{-} \rightarrow Cd(s)$ ....... (2)

Hence, balance the half reactions by multiplying equation (1) by 2 and equation (2) by 3.

Therefore, net cell reaction is as follows.

$2In(s) \rightarrow 2In^{3+}(aq) + 6e^{-}$

$3Cd^{2+}(aq) + 6e^{-} \rightarrow 3Cd(s)$

Net reaction: $2In(s) + 3Cd^{2+}(aq) \rightarrow 2In^{3+}(aq) + 3Cd(s)$

Thus, we can conclude that the overall cell reaction is as follows.

$2In(s) + 3Cd^{2+}(aq) \rightarrow 2In^{3+}(aq) + 3Cd(s)$

4 0

3 years ago

Classify each of the following properties as physical or chemical: A. Ice melts in the sun. B. Copper is a shiny metal. C. Paper

vampirchik [111]

Answer:

The answer to your question is below

Explanation:

Physical properties are the properties in which there is no change in the nature of the substance but there is a change in the physical state.

Chemical properties are the properties in which the substance changes its nature. A new substance is formed.

A. Ice melts in the sun. Physical p.

B. Copper is a shiny metal. Physical p.

C. Paper can burn. Chemical p.

D. A silver knife can tarnish. Physical p.

E. A magnet removes iron particles from a mixture. Physical p.

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3 years ago

In the equilibrium and concentration gizmo, you learned that you can predict the direction of a reaction by comparing the reacti

max2010maxim [7]

And the significant amount of volume can be differed by its solitude

4 0

3 years ago