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Vaselesa [24]
2 years ago
14

In order for matter or energy to be conserved, one must have a ____ system.

Chemistry
2 answers:
Oliga [24]2 years ago
7 0

Answer:

B. closed

Explanation:

In an open system both matter and energy is exchanged with the surroundings. Thus option A is incorrect.  

In a closed system, matter is not transferred but energy is exchanged. Option B is correct.

Isolated system does not allow the exchange of matter or energy.

Options C and D are incorrect as there are no systems in thermodynamics called unique and stationary.  

Leya [2.2K]2 years ago
6 0
Closed system.  If the system is not closed, matter or energy can escape from the system.  an example of this is if you react magnesium and hydrochloric acid in a open system.  The H₂ gas is going to escape making it look like some of the mass disappeared .  in that same reaction some in an open system will also loose heat to the surrounding which will make it look like less heat was produced.
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What kind of energy does a rubber band have when stretched
ICE Princess25 [194]
Elastic potential energy
4 0
3 years ago
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Using the Bohr model, determine the energy in joules of the photon produced when an electron in a Li2+ ion moves from the orbit
djverab [1.8K]

Answer:

1.64x10⁻¹⁸ J

Explanation:

By the Bohr model, the electrons surround the nucleus of the atom in shells or levels of energy. Each one has it's energy, and the electron doesn't fall to the nucleus because it can reach another level of energy, and then return to its level.

When the electrons go to another level, it absorbs energy, and then, when return, this energy is released, as a photon (generally as luminous energy). The value of the energy can be calculated by:

E = hc/λ

Where h is the Planck constant (6.626x10⁻³⁴ J.s), c is the light speed (3.00x10⁸ m/s), and λ is the wavelength of the photon.

The wavelength can be calculated by:

1/λ = R*(1/nf² - 1/ni²)

Where R is the Rydberg constant (1.097x10⁷ m⁻¹), nf is the final orbit, and ni the initial orbit. So:

1/λ = 1.097x10⁷ *(1/1² - 1/2²)

1/λ = 8.227x10⁶

λ = 1.215x10⁻⁷ m

So, the energy is:

E = (6.626x10⁻³⁴ * 3.00x10⁸)/(1.215x10⁻⁷)

E = 1.64x10⁻¹⁸ J

3 0
3 years ago
Isotopes of the same element have different numbers of<br> protons<br> electrons<br> neutrons
MrRa [10]

Answer:

Protons and electrons

Explanation:

They have a different number of neutrons giving them a different atomic weight while having the same charge

6 0
3 years ago
You have 100 mL of a solution of benzoic acid in water; the amount of benzoic acid in the solution is estimated to be about 0.30
dimaraw [331]

Answer:

0.00370 g

Explanation:

From the given information:

To determine the amount of acid remaining using the formula:\dfrac{(final \ mass \ of \ solute)_{water}}{(initial \ mass \ of \ solute )_{water}} = (\dfrac{v_2}{v_1+v_2\times k_d})^n

where;

v_1 = volume of organic solvent = 20-mL

n = numbers of extractions = 4

v_2 = actual volume of water = 100-mL

k_d = distribution coefficient = 10

∴

\dfrac{(final \ mass \ of \ solute)_{water}}{0.30  \ g} = (\dfrac{100 \ ml}{100 \ ml +20 \ ml \times 10})^4

\dfrac{(final \ mass \ of \ solute)_{water}}{0.30  \ g} = (\dfrac{100 \ ml}{100 \ ml +200 \ ml})^4

\dfrac{(final \ mass \ of \ solute)_{water}}{0.30  \ g} = (\dfrac{1}{3})^4

\dfrac{(final \ mass \ of \ solute)_{water}}{0.30  \ g} = 0.012345

Thus, the final amount of acid left in the water = 0.012345 * 0.30

= 0.00370 g

3 0
3 years ago
The discrete group of atoms that are held together by sharing valence electrons
Pepsi [2]

Answer:

Molecule

Explanation:

Molecule is defined as the discrete group of atoms that are held together by sharing valence electrons.

This is because two or more atoms is known as a molecule and for electron sharing to occur then there must be a minimum of two atoms which is also known as a molecule present in the sharing process.

5 0
3 years ago
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