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Lilit [14]
3 years ago
6

Which electron configuration represents a selenium atom in an excited state?(1) 2-7-18-6(2) 2-7-18-7(3) 2-8-18-6(4) 2-8-18-7

Chemistry
1 answer:
rosijanka [135]3 years ago
5 0
(2) 2 - 7 - 18 - 7 does, because the electron from the L shell jumped to the N shell, which requires energy.

The rest of them are either different types of atoms (different elements) or are not the excited state (ground state)
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Lipase is a protein that helps the body break down fats in foods. Lipase is best classified as which type of protein? an enzyme
AlexFokin [52]

Answer:

Lipase is an enzyme the body uses to break down fats in food so they can be absorbed in the intestines.

Explanation:

i hope this will help you :)

7 0
4 years ago
There are two physical properties of minerals that both result in smooth, flat surfaces with specific angles between them. The f
stich3 [128]

Answer:

3. crystal habit and cleavage.

Explanation:

Crystal habit is a distinctive characteristic which is shown in its general shape,  crystallographic forms, how developed each form is.

Cleavage is the ability of a mineral to break in smooth planes parallel to zones of weak bonding. Cleavage in three directions at right angles (90o). Cubic cleavage. Cleavage in three directions not at right angles (120o and 60o).

3 0
3 years ago
Use the equation n2 + 3h2=2nh3 if 8.0g N2 react, how many grams of NH3 will be produced
Eduardwww [97]

the balanced equation for the formation of ammonia is

N₂ + 3H₂ ---> 2NH₃

molar ratio of N₂ to NH₃ is 1:2

mass of N₂ reacted is 8.0 g

therefore number of N₂ moles reacted is - 8.0 g / 28 g/mol = 0.286 mol

according to the molar ratio,

1 mol of N₂ will react to give 2 mol of NH₃, assuming nitrogen is the limiting reactant

therefore 0.286 mol of N₂ should give - 2 x 0.286 mol = 0.572 mol of NH₃

therefore mass of NH₃ formed is - 0.572 mol x 17 g/mol = 9.72 g

a mass of 9.72 mol of NH₃ is formed

6 0
3 years ago
HC2H3O2 (aq) + H2O (l) ⇔ C2H3O2- (aq) + H3O+ (aq) Ka = 1.8 x 10-5
marin [14]

The concentration of [H3O⁺]=2.86 x 10⁻⁶ M

<h3>Further explanation</h3>

In general, the weak acid ionization reaction  

HA (aq) ---> H⁺ (aq) + A⁻ (aq)  

Ka's value  

\large {\boxed {\bold {Ka \: = \: \frac {[H ^ +] [A ^ -]} {[HA]}}}}

Reaction

HC₂H₃O₂ (aq) + H₂O (l) ⇔  (aq) + H₃O⁺ (aq) Ka = 1.8 x 10⁻⁵

\tt Ka=\dfrac{[C_2H_3O^{2-}[H_3O^+]]}{[HC_2H_3O_2]}}\\\\1.8\times 10^{-5}=\dfrac{0.22\times [H_3O^+]}{0.035}

[H₃O⁺]=2.86 x 10⁻⁶ M

5 0
3 years ago
Please Need help asap
ruslelena [56]

Answer:

A

Explanation:

The number of protons and neutrons of an element is the same. the electrons are the only thing that can differ.  The atomic number equal the protons and neutrons.

4 0
3 years ago
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