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Mandarinka [93]
2 years ago
5

Which element has the electron configuration 1s2 2s2 2p6 3s2 3p6 4s2 3d11 4p4?

Chemistry
1 answer:
pickupchik [31]2 years ago
4 0
<span>Selenium (se) 
........
.....</span>
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What is the mass of 2.542 × 1026 atoms of F?
stiks02 [169]

Answer:

7.98 × 10^3grams.

Explanation:

To find the mass of fluorine in the number of atoms provided, we first divide the number of atoms by Avagadros number (6.02 × 10^23atoms) to get the number of moles in the fluorine atom. That is;

number of moles (n) = number of atoms (nA) ÷ 6.02 × 10^23 atoms

n = 2.542 × 10^26 ÷ 6.02 × 10^23

n = 0.42 × 10^ (26-23)

n = 0.42 × 10^3

n = 4.2 × 10^2moles

Using mole = mass ÷ molar mass

Molar/atomic mass of fluorine (F) = 19g/mol

mass = molar mass × mole

Mass (g) = 19 × 4.2 × 10^2

Mass = 79.8 × 10^2

Mass = 7.98 × 10^3grams.

8 0
3 years ago
2 CuCl2 + 4 KI → 2 CuI + 4 KCl + I2
Margaret [11]

Answer: 6.75 moles

Explanation:

This is a simple stoichiometry proboe. that I would set up like this:

(13.5 moles CuCI2) (1 mol I2 / 2 moles CuCi2)

That means you all you have to do for this problem is divide by 2 and cancel out the unit moles CuCI2, which leaves you with 6.75 moles I2.

Hope this helps :)

7 0
3 years ago
A chemistry student is given 600. mL of a clear aqueous solution at 37.° C. He is told an unknown amount of a certain compound X
barxatty [35]

Answer:

  • <u>Yes, it is 14. g of compound X in 100 ml of solution.</u>

Explanation:

The relevant fact here is:

  • the whole amount of solute disolved at 21°C is the same amount of precipitate after washing and drying the remaining liquid solution: the amount of solute before cooling the solution to 21°C is not needed, since it is soluble at 37°C but not soluble at 21°C.

That means that the precipitate that was thrown away, before evaporating the remaining liquid solution under vacuum, does not count; you must only use the amount of solute that was dissolved after cooling the solution to 21°C.

Then, the amount of solute dissolved in the 600 ml solution at 21°C is the weighed precipitate: 0.084 kg = 84 g.

With that, the solubility can be calculated from the followiing proportion:

  • 84. g solute / 600 ml solution = y / 100 ml solution

      ⇒ y = 84. g solute × 100 ml solution / 600 ml solution = 14. g.

The correct number of significant figures is 2, since the mass 0.084 kg contains two significant figures.

<u>The answer is 14. g of solute per 100 ml of solution.</u>

7 0
2 years ago
In animals. energy is produced by the:
CaHeK987 [17]
It’s c mitochondria
5 0
2 years ago
2) What group of elements are most likely to react with<br><br> helium? Explain why.
Luba_88 [7]

Answer:

Helium does not react with any element

Please find the explanation below

Explanation:

Helium (He) is an element in group 8A of the periodic table, which is a group of element referred to as NOBLE GASES. Other elements in this group are Xenon (Xe), Krypton (Kr), Neon (Ne) etc.

One major characteristics of Helium and other Noble gases that makes them so UNREACTIVE is that they have a full electronic configuration i.e. they have a full electron shell and do not share electrons with any element, which is the basis of REACTING. For this reason, Helium will not react with any element.

7 0
2 years ago
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