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Ratling [72]
3 years ago
5

How many valence electrons are in the outermost energy level of each of the following elements? A. Helium B. Lithium C. Nitrogen

D. Magnesium
Chemistry
1 answer:
aleksklad [387]3 years ago
8 0
<span>A. Helium </span>atomic number 2
hope it helps
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You are running a rather large scale reaction where you prepare the grignard reagent phenylmagnesium bromide by reacting 210.14
almond37 [142]

Answer:

We would expect to form 7.35 moles of grignard reagent.

Explanation:

<u>Step 1: </u>Data given

Mass of magnesium = 210.14 grams

Volume bromobenzene = 772 mL

Density of bromobenzene = 1.495 g/mL

Molar mass of Mg = 24.3 g/mol

Molar mass of bromobenzene = 157.01 g/mol

<u>Step 2</u>: The balanced equation

C6H5Br + Mg ⇒ C6H5MgBr

<u>Step 3:</u> Calculate mass of bromobenzene

Mass bromobenzene = density bromobenzene * volume

Mass bromobenzene = 1.495 g/mL * 772 mL

Mass bromobenzene = 1154.14 grams

<u>Step 4</u>: Calculate number of moles bromobenzene

Moles bromobenzene = mass bromobenzene / molar mass bromobenzene

Moles bromobenzene = 1154.14g / 157.01 g/mol

Moles bromobenzene = 7.35 moles

<u>Step 5:</u> Calculate moles of Mg

Moles Mg = 210.14 grams /24.3 g/mol

Moles Mg = 8.65 moles

<u>Step 6:</u> The limiting reactant

The mole ratio is 1:1 So the bromobenzene has the smallest amount of moles, so it's the limiting reactant. It will be completely consumed ( 7.35 moles). Magnesium is in excess, There will react 7.35 moles. There will remain 8.65 - 7.35 = 1.30 moles

<u>Step 7:</u> Calculate moles of phenylmagnesium bromide

For 1 mole of bromobenzene, we need 1 mole of Mg to produce 1 mole of phenylmagnesium bromide

For 7.35 moles bromobenzene, we have 7.35 moles phenylmagnesium bromide

We would expect to form 7.35 moles of grignard reagent.

5 0
3 years ago
(1) Complete the word equation for the complete combustion of methane in
Deffense [45]

Cooled in ice to help the water vapour condense. Tube 2 – contains lime water, goes cloudy to show the presence of carbon dioxide. Word equation: (hydrocarbon + oxygen → carbon dioxide + water) Methane + oxygen → carbon dioxide + water.

6 0
2 years ago
Which type of rock is most likely to form because of high heat and pressure?
expeople1 [14]

Answer:

Metamorphic Rock

Explanation:

Metamorphic rocks are formed because of high heat and pressure . Metamorphic rocks form from heat and pressure changing the original or parent rock into a completely new rock. The parent rock can be either sedimentary, igneous, or even another metamorphic rock

6 0
3 years ago
Read 2 more answers
In at least 4 complete sentences, describe the similarities and differences between Avogadro's Law and Charles' Law.
viktelen [127]

answer

Avogadro's law states that, at constant temperature and pressure, the volume of a gas is directly proportional to the number of moles present. In other words, equal volumes of gases at the same pressure and temperature contain the same number of molecules - this is true regardless of their physical properties or chemical nature.

This number of molecules is

6.022

⋅

10

23

and is known as Avogadro's number,

N

A

.

Matematically, Avogadro's law can be written like this

V

n

=

c

o

n

s

t

, or, better yet,

V

1

n

1

=

V

2

n

2

.

Avogadro's law, as well as Boyle's law and Charles' law, are special cases of the ideal gas law,

P

V

=

n

R

T

. If temperature and pressure are kept constant, and knowing that

R

is of course constant, then

P

V

=

n

R

T

→

P

V

n

=

R

T

→

V

n

=

R

T

P

=

c

o

n

s

t

, which represents Avogadro's law.

The ideal gas law can also be written to incorporate

N

A

, since the number of moles are actually the number of molecules divided by Avogadro's number

P

V

=

N

N

A

⋅

R

T

, where

N

represents the number of molecules.

7 0
2 years ago
What is the structure of epithelial cells?
EleoNora [17]
Your answer is C for sure
5 0
3 years ago
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