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3 years ago

Which of the following is characterized by existing at a discrete energy level?

Chemistry

2 answers:

Bingel [31]3 years ago

8 0

Answer:

The correct option is: D) Subatomic Particle

Explanation:

Electrons are the negatively charged, stable sub-atomic particles that exist in <u>discrete energy levels, called the electron shells</u>, around the nucleus of an atom.

Each electronic shell consists of a fixed number of electrons and these electronic shells are denoted by the symbol K, L, M, N, and so on.

<u>Therefore, electron is the sub-atomic particle that exists at a discrete energy level.</u>

hichkok12 [17]3 years ago

5 0

Energy levels are considered orbitals.

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Noble gas notation for molybdenum?

GuDViN [60]

Noble gas notation for molybdenum:
[Kr] 4d^5 5s^1

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2 years ago

What type of wave do the contractions of the snake muscles make as the snake moves forward

S_A_V [24]

Actually, there are four kinds of reptile motion:

Concertina - vermiform. Circular muscles around the snake squeeze the front of the snake's body out long, then the latter half is pulled forward.

Rectilinear crawling - Belly scutes are moved forward individually in a wave-like motion.

Side-winding - Snake's version of "walking". Use by several species to move over fluidic substrates, such as sand.

Lateral undulation - Most common form of movement. Snake presses on alternating pressure points to force body forward (or backward)

(taken from a user on Yahoo from Correct Answers)

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3 years ago

Calculate the masses of oxygen and nitrogen that are dissolved in of aqueous solution in equilibrium with air at 25 °C and 760 T

shtirl [24]

Explanation:

Let us assume that the volume of given aqueous solution is 7.5 L.

Therefore, according to Henry's law, the relation between concentration and pressure is as follows.

C = $\frac{P}{K_{h}}$

where, pressure (P) = 760 torr = 1 atm

According to Henry's law, constants for gases in water at $25^{o}C$ are as follows.

$p(O_{2})$ = 0.21 atm = 0.21 bar

$p(N_{2})$ = 0.78 atm = 0.78 bar

$K_{h}$ for $O_{2}$ = $7.9 \times 10^{2} bar/mol$

$K_{h}$ for $N_{2}$ = $1.6 \times 10^{3} bar /mol$

Since, 21% oxygen is present in air so, its mass will be 0.21 g. Similarly, 78% nitrogen means the mass of nitrogen is 0.78 g.

Therefore, concebtrations will be calculated as follows.

$C(O_{2}) = \frac{0.21}{7.9 \times 10^{2}} = 2.66 \times 10^-4 mol/L$

$C(N_2) = \frac{0.78}{1.6 \times 10^3} = 4.875 \times 10^-4 mol/L$

Now, we will calculate the number of moles as follows.

$n(O_{2}) = 7.5 \times 2.66 \times 10^-4 = 1.995 \times 10^-3$ mol

$n(N_2) = 7.5 \times 4.875 \times 10^-4 = 3.66 \times 10^-3$ mol

As the molar mass of $O_2$ = 32 g/mol

Hence, mass of oxygen will be as follows.

Mass of $O_2 = 32 \times 1.995 \times 10^-3 \times 1000$

= 63.84 mg

As the molar mass of $N_{2}$ = 28

Mass of $N_{2} = 28 \times 3.66 \times 10^-3$ = 102.5 mg

Thus, we can conclude that mass of oxygen is 63.84 mg and nitrogen is 102.5 mg.

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3 years ago

Read 2 more answers

Write the concentration equilibrium constant expression for this reaction.

Akimi4 [234]

In a chemical reaction, the equilibrium constant refers to the value of its reaction quotient at chemical equilibrium, that is, a condition attained by a dynamic chemical system after adequate time has passed, and at which its composition has no measurable capacity to undergo any kind of further modification.

The given reaction is: HCN (aq) + OH⁻ = CN⁻ (aq) + H2O (l)

The equilibrium constant = product of concentration of products / product of concentration of reactants

(Here, H2O is not considered as its concentration is very high)

So, Keq = [CN⁻] / [HCN] [OH⁻]

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3 years ago

If 30.5 g of 15% potassium nitrate solution are reacted to excess magnesium chloride how many grams of potassium chloride will b

Nata [24]

Here the step by step and answer

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2 years ago