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Elena-2011 [213]
3 years ago
10

¿Qué son los lantánidos y actínidos?

Chemistry
1 answer:
harkovskaia [24]3 years ago
6 0

Answer: En estos grupos de los elementos de transición se encuentran las llamadas tierras raras, separadas del resto de elementos de la tabla, que pertenecen al grupo IIIB y se les conoce como lantánidos y actínidos.

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12.5 g of copper are reacted with an excess of chlorine gas, and 25.4 g of copper(II) chloride are
Alika [10]

Answer:

Percent yield = 94.5%

Theoretical yield =  26.89 g

Explanation:

Given data:

Mass of copper = 12.5 g

Mass of copper chloride produced = 25.4 g

Theoretical yield = ?

Percent yield = ?

Solution:

Cu + Cl₂  →  CuCl₂

Number of moles of Copper:

Number of moles = mass/ molar mass

Number of moles = 12.5 g/ 63.55 g/mol

Number of moles = 0.2 mol

Now we will compare the moles of copper with copper chloride.

          Cu          :           CuCl₂

           1             :              1

          0.2          :            0.2

Theoretical yield:

Mass of copper chloride:

Mass = Number of moles × molar mass

Mass = 0.2 mol × 134.45 g/mol

Mass = 26.89 g

Percent yield:

Percent yield = Actual yield / theoretical yield  × 100

Percent yield = 25.4 g/26.89 g × 100

Percent yield = 94.5%

8 0
4 years ago
Calculate the equilibrium constant for each of the reactions at 25 ∘C. 2Fe3+(aq)+3Sn(s)→2Fe(s)+3Sn2+(aq)
iragen [17]
We take activities of Solids and liquids equal 1. The reason is there concentrations not at all change amount of reactant at equilibrium in the reaction. Hence we don't consider concentrations of pure solids and liquids while writing equilibrium constant. So for above reaction, equilibrium constant (K) = [Sn^2 +] ^3 x 1 / [Fe^3+]^2 x 1. Ping me if you have any doubts.
7 0
3 years ago
Consider a hexagonal close-packed unit cell as shown here.
Alenkinab [10]
Sorry, but I can't help unless you post a diagram or picture. If you can't, what about a written description?
7 0
4 years ago
What is the difference between diffusion and osmoses<br><br>​
Citrus2011 [14]

Answer:

Diffusion means that particles travel from a higher concentration to a lower concentration region before balance is achieved. The semi-permeable membrane is present in osmosis, so that only solvent molecules can travel freely to equalize the levels.

5 0
3 years ago
How is the separation of dna like a zipper
Sedbober [7]

The two strands must be separated like the two sides of a zipper, by breaking the weak hydrogen bonds that link the paired bases.

<u>Explanation:</u>

  • A double helix structure formed by two polypeptide chains is separated like the two sides of a zipper. A zipper is formed by breaking the weak hydrogen bonds that link the paired bases. During replication, an enzyme "Helicase" travels down the DNA and splits the chain and it forms 2 separate strands.
  • The two DNA strand which has the same sequence must be separated like the two sides of a zipper by breaking weak hydrogen bases. During base pair-rule, the strand are unzipped and each strands is copied.

     

3 0
3 years ago
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