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gregori [183]
3 years ago
8

If we have any substance it can be concluded that a chemical change has happened if​

Chemistry
1 answer:
Nadusha1986 [10]3 years ago
7 0

Answer:

You cannot reverse the effects.

Explanation:

In physical changes you can usually reverse the effects for example if ice melts you can just refreeze it. But it's impossible to reverse a chemical change such as a rusted bike.

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Which structures main function is to produce food (sugar) in a plant
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Chloroplasts is the answer
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3 years ago
Predict the ground-state electron configuration of the following ions. Write your answers in abbreviated form, that is, beginnin
abruzzese [7]

These are three questions and three complete answers

Answer:

a) Cr²⁺: [Ar] 4s² 3d²

b) Cu²⁺: [Ar] 4s² 3d⁷

c) Co³⁺: [Ar] 4s² 3d⁴

Explanation:

<u>a) Cr²⁺</u>

  • Z = 24
  • Number of protons: 24
  • Number of elecrons of the neutral atom: 24
  • Charge of the ions: + 2
  • Number of electrons of the ion: 24 - charge = 24 - 2 = 22.
  • Electron configuration:

       Fill the orbitals in increasing order of energy. Using Aufbau's rules the order is: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ .....

       Hence, for 22 electrons you get:

       1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d²

  • Abbreviated notation: since the last complete level is the number 3s² 3p⁶, you use the noble gas of the period 3, which is Ar, and the configuration is:

       

        [Ar] 4s² 3d²

<u>b) Cu²⁺</u>

  • Z = 29
  • Number of protons: 29
  • Number of elecrons of the neutral atom: 29
  • Charge of the ion: + 2
  • Number of electrons of the ion: 29 - charge = 29 - 2 = 27.
  • Electron configuration:

       Fill the orbitals in increasing order of energy. Using Aufbau's rules the order is: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ .....

       Hence, for 27 electrons you get:

       1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁷

  • Abbreviated notation: since the last complete level is the number 3s² 3p⁶, you use the noble gas of the period 3, which is Ar, and the configuration is:

       

        [Ar] 4s² 3d⁷

<u>c) Co³⁺</u>

  • Z = 27
  • Number of protons: 27
  • Number of elecrons of the neutral atom: 27
  • Charge of the ion: + 3
  • Number of electrons of the ion: 27 - charge = 27 - 3 = 24.
  • Electron configuration:

       Fill the orbitals in increasing order of energy. Using Aufbau's rules the order is: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ .....

       Hence, for 24 electrons you get:

       1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁴

  • Abbreviated notation: since the last complete level is the number 3s² 3p⁶, you use the noble gas of the period 3, which is Ar, and the configuration is:

       

        [Ar] 4s² 3d⁴

6 0
3 years ago
A sample of ammonia (NH3) gas is completely decomposed to nitrogen and hydrogen gases over heated iron wool. If the total pressu
DochEvi [55]

Answer:

539.3mmHg of H₂

179.7mmHg of N₂

Explanation:

Ammonia, NH₃, reacts completely producing N₂ and H₂ thus:

2 NH₃ → N₂ + 3H₂

<em>That means there are produced 4 moles of gases and 3 are of H₂ and 1 of N₂</em>

Total pressure (Sum of pressures of N₂ and H₂) is 719mmHg. 3 parts are of H₂ and 1 of H₂

Thus, partial pressures of the products after reaction are:

719mmHg ₓ (3 H₂ / 4) = 539.3mmHg of H₂

719mmHg ₓ (1 N₂ / 4) = 179.7mmHg of N₂

8 0
3 years ago
Magnesium (24.30 g) reacts with hydrogen chloride (X g) to produce hydrogen gas (2.04 g) and magnesium chloride (96.90 g). How m
makvit [3.9K]

Answer:

74.64\ \text{g}

Explanation:

Reactants

Magnesium = 24.3 g

Hydrogen chloride= x g

Products

Hydrogen gas = 2.04 g

Magnesium chloride = 96.9 g

As the mass of the reactions is conserved we have

Mass of reactants = Mass of products

24.3+x=2.04+96.9\\\Rightarrow x=2.04+96.9-24.3\\\Rightarrow x=74.64\ \text{g}

Mass of hydrogen chloride is 74.64\ \text{g}.

7 0
3 years ago
The force that one surface exerts on another when the 2 rub against each other is called
Sav [38]
The friction force
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5 0
3 years ago
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