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Vadim26 [7]
3 years ago
5

What is the electron configuration of an element with atomic number 20? A. 1s2 2s2 2p6 3s2 3p5 B. 1s2 2s2 2p6 3s2 3p6 C. 1s2 2s2

2p6 3s2 D. 1s2 2s2 2p6 3s2 3p6 4s2 E. 1s2 2s2 2p6
Chemistry
2 answers:
Cerrena [4.2K]3 years ago
8 0

D.  The number of electrons equals the atomic number for a neutral element.  Each number after the letter refers to the number of electrons in that shell.  So for D, 2+2+6+2+6+2 = 20 electrons, which is equal to the atomic number.

Leni [432]3 years ago
6 0

D. 1s2 2s2 2p6 3s2 3p6 4s2

Hope this helps!

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How do you find the molecular formula from the empirical formula?
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Niven wants to calculate the mass of mgo that is produced by burning of 28.0g of mg. What is the first step in nivens calculatio
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Answer: -

The experiment Niven is doing is burning of Mg.

The first step would be finding the molar mass of MgO

Atomic mass of Mg = 24 g

Atomic mass of Oxygen = 16 g

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2 Mg + O2 -- > 2MgO

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In the "Méthode Champenoise," grape juice is fermented in a wine bottle to produce sparkling wine. The reaction is the following
prohojiy [21]

Answer:

The pressure inside the wine bottle at 21 °C is 4.8 · 10² atm

Explanation:

Hi there!

We know that 1 mol of CO₂ is produced per mol of produced ethanol.

If the final concentration of ethanol is 13%, let´s calculate how many moles of ethanol are present at that concentration.

A concentration of 13% means that in 100 ml of solution, 13 ml is dissolved ethanol. We have 754 ml of solution, then, the volume of ethanol will be:

754 ml solution · (13 ml ethanol/100 ml solution) = 98 ml ethanol

With the density, we can calculate the mass of ethanol present:

density = mass/ volume

0.79 g/ml = mass / 98 ml

mass = 0.79 g/ml · 98 ml

mass = 77 g

The molar mass of ethanol is 46.07 g/mol, then 77 g of ethanol is equal to:

77 g · (1 mol/46.07 g) = 1.7 mol

Then, the number of moles of CO₂ produced will be 1.7 mol.

Using the equation of the ideal gas law, we can calculate the pressure of CO₂:

P = nRT/V

Where:

P = pressure

n = number of moles

R = ideal gas constant

T = temperature

V = volume

The volume will be the headspace of the bottle (840 ml - 754 ml) 86 ml = 0.086 l.

The temperature in kelvin will be: 21 + 273 = 294 K

The gas constant is 0.082 l atm / K mol

Then:

P = (1.7 mol · 0.082 l atm/K mol · 294 K)/ 0.086 l

P = 4.8 · 10² atm

The pressure inside the wine bottle at 21 °C is 4.8 · 10² atm

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2 years ago
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