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3 years ago

State three reasons why air is •Chassifield as a mixtureOne is through sublimation

Chemistry

1 answer:

ivolga24 [154]3 years ago

8 0

Answer:

Air is considered as a mixture because it is composed of various separate components. The air has no characteristic properties of its own. ur welcome :)

Explanation:

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You weigh a 24K gold chain and find that it weighs 400 grams. Determine home many moles of gold atoms you have

makkiz [27]

Answer:

2.03 moles of Gold

Explanation:

Gold is one of the most precious metal metal used in many applications and mainly as a jewellery. In terms of purity it is categorized in Karats. 24 Karat is considered the purest Gold (i.e. 100 % Gold) while other Karats (14, 18, 22 e.t.c) are alloys with other metals and gyms.

Data Given:

Mass of Gold = 400 g

A.Mass of Gold = 196.97 g.mol⁻¹

Calculate Moles of Gold as,

Moles = Mass ÷ M.Mass

Putting values,

Moles = 400 g ÷ 196.97 g.mol⁻¹

Moles = 2.03 moles of Gold

4 0

3 years ago

Which electron configuration represents the electrons of an atom in an excited state? * 2-3 2-7-1 2-8 2-8-1

Lemur [1.5K]

2-7-1

<h3>Further explanation </h3>

Electrons can move the shell up or down by releasing energy or absorbing energy

Excited electrons show higher electron transfer to the shell by absorbing energy

So it can be concluded that there are 2 conditions:

Ground state is the state of electrons filling shell with the lowest energy levels.

Excited state is the state of electrons which occupies a higher energy level

The state of excited electrons can be seen from the presence of electrons which do not fill the skin completely but fill the skin afterward

2-7-1

From its 8 electron configuration, filling 3 shells, 2 electrons in the firs shell, 7 electrons in the second shell and 1 electron in the third shell

the electrons in the third shell should fill the electrons in the second shell first according to Aufbau rule (lower energy shells)

$\tt 1s^22s^22p^4\rightarrow ground~state\\\\1s^22s^22p^33s^1\rightarrow excited~state$

8 0

3 years ago

Maggie has 4 binders with 30 stamps in each binder. She has 3 binders with 36 baseball cards in each binder. If she gives away 4

Sliva [168]

Answer:

The number of stamps and cards Maggie has left if she gives 45 stamps to a friend is 183

Explanation:

If Maggie gives 45 stamps to a friend, you must calculate the number of stamps and cards she has left.

You know Maggie has 4 folders with 30 stamps in each folder. So the number of stamps she owns is calculated as:

4 folders*30 stamps in each folder= 120 stamps

If Maggie gives 45 stamps to a friend, then the number of stamps she has left will be calculated as the difference (the subtraction) between the stamps she owned and the ones she gives away:

120 stamps - 45 stamps= 75 stamps

On the other hand, she has 3 binders with 36 baseball cards in each binder. So the number of cards she owns is calculated as:

3 binders * 36 baseball cards in each binders= 108 baseball cards

The number of stamps and cards you have left is calculated as:

75 stamps + 108 baseball cards= 183

<em><u>The number of stamps and cards Maggie has left if she gives 45 stamps to a friend is 183</u></em>

4 0

3 years ago

A) Calculate the osmotic pressure difference between seawater and fresh water. For simplicity, assume thatall the dissolved salt

never [62]

Answer:

a) Δπ = 1.264 atm

b) W = 128 joules

c) ΔH >> W ( a factor greater than 17,000 )

Explanation:

a) The osmotic pressure, π , is determined by :

π = nRT/V, where n= moles of solute

R= 0.0821 Latm/kmol

T = 300 K

calling π(sw) osmotic pressure for for sea water and π (fw) for fresh water,

salinity of sea water = 3.5 g / 1L water (assuming only NaCl for the salts)

salinity of fresh water = 0.5 parts per thousand (range: 0- 0.5 ppt)

πsw = (3.5 g/58.44 g/mol) (0.0821 Latm/Kmol) (300 K ) /1 L = 1.475 atm

πfw = (0.5 g/58.44 g/mol) (0.0821 Latm/Kmol) (300 K ) /1 L = 0.211 atm

d water = 1 g/cm³

Δ π = (1.475 - 0.211) = 1.264 atm

b) W = Δπ V = 1.426 atm x 1L = 1.43 L-atm

1 L-atm = 101.33 j

W = 101.33 j/ Latm x 1.43 Latm = 128 joules

c) ΔH = Q₁ + nΔH vap, where

Q₁ = heat required to bring the solution from 300 K to boiling, 373 K

ΔH vap = heat of vaporization

Q = mCΔT = 1000 g x 4.186 j x 73 K = 305.6 j = 0.3056 kj

ΔH vap = (1000 g/ 18 g/mol ) 40.7 kj/mol = 2,261 kj

ΔH = 0.3056 kj + 2,261 kj = 2,261.3 kj

Note = Q << ΔH vap and we could have neglected it.

This result shows why nobody talks about evaporation of sea water to produce fresh water ΔH >> W

6 0

3 years ago

When a 235 92U nucleus is bombarded by neutrons (10n) it undergoes a fission reaction, resulting in the formation of two new nuc

user100 [1]

Answer:

$^{139}_{56}Ba$

Explanation:

The fission reaction taking place given in the question is:

$^{235}_{92}U+^{1}_{0}n\rightarrow ^{A}_{Z}Ba+^{94}_{36}Kr+3^{1}_{0}n$

The mass is conserved in the reaction.

So,

235 + 1 = A + 94 + 3×1

A = 139 g/mol

Also, number o protons remain same. So,

92 = Z + 36

Z = 56

The isotopic symbol is $^{139}_{56}Ba$

5 0

3 years ago

State three reasons why air is •Chassifield as a mixtureOne is through sublimation​

State three reasons why air is •Chassifield as a mixtureOne is through sublimation