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Vinvika [58]
3 years ago
14

How to know how many valence electrons are in an element

Chemistry
1 answer:
Alenkinab [10]3 years ago
7 0

Answer:

Hope it helped

Explanation:

For neutral atoms, the number of valence electrons is equal to the atom's main group number. The main group number for an element can be found from its column on the periodic table. For example, carbon is in group 4 and has 4 valence electrons. Oxygen is in group 6 and has 6 valence electrons.

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.500 mol of br2 and .500 mol of cl2 are placed in a .500L flask and allowed to reach equilibrium. at equilibrium the flask was f
Tasya [4]

Answer : The value of K_c for the given reaction is, 0.36

Explanation :

Equilibrium constant : It is defined as the equilibrium constant. It is defined as the ratio of concentration of products to the concentration of reactants.

The equilibrium expression for the reaction is determined by multiplying the concentrations of products and divided by the concentrations of the reactants and each concentration is raised to the power that is equal to the coefficient in the balanced reaction.

As we know that the concentrations of pure solids and liquids are constant that is they do not change. Thus, they are not included in the equilibrium expression.

The given equilibrium reaction is,

Br_2(aq)+Cl_2(aq)\rightleftharpoons 2BrCl(aq)

The expression of K_c will be,

K_c=\frac{[BrCl]^2}{[Br_2][Cl_2]}

First we have to calculate the concentration of Br_2,Cl_2\text{ and }BrCl.

\text{Concentration of }Br_2=\frac{Moles}{Volume}=\frac{0.500mol}{0.500L}=1M

\text{Concentration of }Cl_2=\frac{Moles}{Volume}=\frac{0.500mol}{0.500L}=1M

\text{Concentration of }BrCl=\frac{Moles}{Volume}=\frac{0.300mol}{0.500L}=0.6M

Now we have to calculate the value of K_c for the given reaction.

K_c=\frac{[BrCl]^2}{[Br_2][Cl_2]}

K_c=\frac{(0.6)^2}{(1)\times (1)}

K_c=0.36

Therefore, the value of K_c for the given reaction is, 0.36

6 0
3 years ago
Read 2 more answers
An atom that has 13 protons and 15 neutrons is isotope of the element A.) nickel B.) silicon C.) aluminum D.) phosphorus. Why?
joja [24]

An atom that has 13  protons and 15  neutrons  is isotope  of Aluminium (answer C)

<u><em>Explanation</em></u>

  • Isotope  is a form of the same element with   the equal number of protons but difference number  of neutrons  in  their nuclei.
  • In other words isotope has the same  atomic number but different mass  number.
  • Atomic  number of a element is determined by number of  protons of an element.

  • from the  periodic table   Aluminum in atomic number 13 therefore  it has 13 protons  <em>therefore an atom that  has 13  protons and 15 neutrons is   a isotope  of Aluminium. </em>
6 0
3 years ago
Read 2 more answers
Round to four significant figures 0.00238866
mixas84 [53]
0.0024 Is it rounded to four significant figures
6 0
3 years ago
Calculate the entropy change for the reaction: Fe2O3(s) +3C(s) -&gt; 2Fe(s) + 3CO(g)
Gelneren [198K]

Answer:

ΔS = +541.3Jmol⁻¹K⁻¹

Explanation:

Given parameters:

Standard Entropy of Fe₂O₃ = 90Jmol⁻¹K⁻¹

Standard Entropy of C = 5.7Jmol⁻¹K⁻¹

Standard Entropy of Fe = 27.2Jmol⁻¹K⁻¹

Standard Entropy of CO = 198Jmol⁻¹K⁻¹

To find the entropy change of the reaction, we first write a balanced reaction equation:

                              Fe₂O₃ +  3C →  2Fe + 3CO

To calculate the entropy change of the reaction we simply use the equation below:

      ΔS = ∑S_{products} - ∑S_{reactants}

Therefore:

     ΔS = [(2x27.2) + (3x198)] - [(90) + (3x5.7)] = 648.4 - 107.1

                          ΔS = +541.3Jmol⁻¹K⁻¹

5 0
3 years ago
Which of the following are evidence that chemical change has occurred
dolphi86 [110]

Answer:

gas given off

Explanation:

that's the answer

3 0
3 years ago
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