what is the formula for zinc sulfide

Answer:

The answer is

[tex]3.77 \times {10}^{15} \: \: \: Hz[/tex]

Explanation:

The frequency of the photon can be found by using the formula

[tex]f = \frac{E}{h} \\ [/tex]

where

E is the energy

f is the frequency

h is the Planck's constant which is

6.626 × 10-³⁴ Js

From the question

E = 2.50 × 10^-18 J

So we have

[tex]f = \frac{2.50 \times {10}^{ - 18} }{6.626 \times {10}^{ - 34} } \\ [/tex]

We have the final answer as

[tex]3.77 \times {10}^{15} \: \: \: Hz[/tex]

Hope this helps you

Answer:

Ok what question

Explanation:

Answer:

Distillation will be the best method for the separation of solute from the solvent in a solution.

Explanation:

Answer:

25 g

Explanation:

The following data were obtained from the question:

Half life (t½) = 5 s

Original amount (N₀) = 100 g

Time (t) = 10 s

Amount remaining (N) =..?

Next, we shall determine the decay constant for the disintegration. This can be obtained as follow:

Half life (t½) = 5 s

Decay constant (K) =.?

K = 0.693 / t½

K = 0.693 / 5

K = 0.1386 s¯¹

Finally, we shall determine the amount of the isotope that remained after 10 s as follow:

Original amount (N₀) = 100 g

Time (t) = 10 s

Decay (K) = 0.1386 s¯¹

Amount remaining (N) =..?

Log (N₀/N) = kt /2.303

Log (100/N) = (0.1386 × 10) / 2.303

Log (100/N) = 1.386 / 2.303

Log (100/N) = 0.6018

Take the anti log of 0.6018

100/N = antilog (0.6018)

100/N = 4

Cross multiply

100 = N × 4

Divide both side by 4

N = 100/4

N = 25 g

Therefore, the amount remaining after 10 s is 25 g

Answer:

C I think.

Explanation:

Sorry if it's wrong :(

the answer is B transfer thru direct contact

Answer:

Lithium would require the least amount of energy to remove an electron

Answer:

The answer is actually sodium

Explanation:

Lithium actually requires more than sodium.

Answer: Water is considered neutral because the concentration of hydrogen and hydroxide ions is the same

Explanation:

Answer:

37 negative charges.

Explanation:

We're being asked to determine how many negative charges a drop contains from an oil drop experiment where the total charge was 5.93x10-18 C. The drop contains 37 negative charges.

It was stated and identified that we are to attempt question #51 alone.

From the given information;

The total charge on an oil drop = 5.93 × 10⁻¹⁸ C

According to Oil drop experiment carried out by Robert Milliken in (1910);

In the oil drop laboratory experiment, It was possible for Him to substitute oil for water (because water quickly evaporate). Robert Milikan adjusted the electrical voltage among the two metal plates while the oil drop continues to drop until it stopped. When the drop was stopped, the gravitational downward force on the oil drop was equivalent to the electrical upward force on the charges thereby enabling Robert Millikan to be able to estimate the electrical charge drop.

Robert Milliken identified that the magnitude of a single negative electron charge is:

= 1.6 × 10⁻¹⁹ C

∴

If in an experiment, the total charge =  5.93 × 10⁻¹⁸ C

Then;

The number of negative charges in the oil drop can be calculated as;

[tex]\mathbf{=\dfrac{5.93 \times 10^{-18}}{1.6 \times 10^{-19}}}[/tex]

= 37.063 negative charges

Therefore, we can conclude that the numbers of negative charges contained in the total drop = 37.063.

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Answer:

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

[tex]n = \frac{N}{L} \\ [/tex]

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

[tex]n = \frac{2.16 \times {10}^{26} }{6.02 \times {10}^{23} } \\ = 358.80398671...[/tex]

We have the final answer as

Hope this helps you

-1

........... ..............

Answer:

Tobacco use: The most preventable cause of cancer death

Explanation:

cancer might not be right

Answer:

C. Elements bond in a multitude of ways to make compounds.

Answer:

Any planet that is made up of mostly rock.

Answer:

As a seed plant grows, the roots grow downward due to the force of​  Gravity

Explanation:

A seed is planted upside-down, but the roots still grow in the direction of gravity.

Answer:

Obviously, it's gravity

Explanation:

Answer:

Overfishing

Explanation:

The aquatic biomes of the Philippines' are rich in coral reefs and other aquatic animals but they are under major threat due to pollution and overfishing.

Pollution is caused by industrial factories and coastal developments. Industrial factories fed all it waste in the aquatic biomes and coastal developments due to the increasing population of the Philippines causes mass pollution by the dumping of waste materials and sedimentation.

Overfishing exploits the fish species and also affects the food cycle in aquatic biomes.

As a student, we can spread awareness by conducting awareness campaigns and can take the help of news channels to let people know the consequences of aquatic biomes exploitation. We can also use social media which is popular nowadays to introduce facts about the causes and consequences of aquatic biomes exploitation.

A descriptive model of Earth's layers can be categorized as prototype model. Hence, option B is correct.

What is a descriptive model?

A descriptive model describes a system or other entity and its relationship to its environment.

The Earth has different compositional and mechanical layers. Compositional layers are determined by their components, while mechanical layers are determined by their physical properties.

The outermost solid layer of a rocky planet or natural satellite. Chemically distinct from the underlying mantle.

Hence, option B is correct.

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Answer: The formula for magnesium carbonate is MgCO_3.

Explanation:

Answer:

88.2 gram of aluminium .

Explanation:

6Li + Al₂ ( SO₄)₃ = 3Li₂SO₄ + 2Al

6 x 7 g                                    2 x 27 g

42 gram of lithium produces     54 gram of aluminium

68.6 gram of lithium will produce   88.2 gram of aluminium .

88.2 gram of aluminium will be produced.        

Answer:

I will not consider electronic mass here. We know (the masses should have been provided in the question!) that the neutron mass is

1.008701

⋅

amu

and the proton mass is

1.007316

⋅

amu

.

Explanation:

Question answered

Answer:

C

Explanation:

(A+B) are compounds and D is mixtures

Answer:

Explanation:

molecular weight of potassium hydrogen phthalate = 204

.8094 g of KHP = .8094 / 204 = 3.967 x 10⁻³ moles

3.967 x 10⁻³ moles of KHP must have reacted with 3.967 x 10⁻³ moles of NaOH

concentration of NaOH = 3.967 x 10⁻³ / 40.25 x 10⁻³

= .098 M .

Answer:

46

Explanation:

Answer: 4418.6

Explanation:

Answer:

The atoms in the solid would be vibrating in position.

Explanation:

i took the test

Three grams of the same substance in different phases are stored in three different containers. Each container is barely large enough to hold the substance. Therefore, the correct option is option B.

Atom, the smallest unit of matter that may be separated without releasing electrically charged particles. It is also the tiniest unit of matter with the characteristics of a chemical substance. As a result, the atomic is the fundamental building component of chemistry.

The majority of the molecule is empty space. The rest of the structure is made up of a positive-charged nucleus of neutrons and protons surrounding by a swarm of negative-charged electrons. In comparison to electrons, the lightest charge particles in nature, nuclear nucleus is small yet dense. The atoms in the liquid would be vibrating in position.

Therefore, the correct option is option B.

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Answer:

This statement is the definition of law of conservation of mass.

Explanation:

Law of conservation of mass:

According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.

This law was given by French chemist  Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.

For example:

In given photosynthesis reaction:

6CO₂ + 6H₂O   →   C₆H₁₂O₆ +  6O₂

there are six carbon atoms, eighteen oxygen atoms and twelve hydrogen atoms on the both side of equation so this reaction followed the law of conservation of mass.

Let us consider the general chemical reaction.

A   +   B    →      C

5g +  5g           10g

Answer:

Answer

The answer is option 4

The energy transformation during nutrients transportation across the cell membrane is transformation from chemical energy to kinetic energy, where the uphill and downhill movements of molecules based on concentration gradient carries the whole process.

The total energy in a system is always conserved. However, one form of energy can be transformed into another form. For example we uses electrical devices such as bulbs fan etc, wherever the energy transformation is getting way from electrical energy to light or mechanical energy.

In plant cells nutrient molecules and ions are balanced inside and outside the cell and hence they are transported across the cell membrane by a concentration gradient with a chemical energy produced by the molecules.

The chemical energy inside of the ions and molecules converts to kinetic energy to transport itself through downhill and uphill mechanisms with aid of various enzymes and electron channels.

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Answer:

They would produce a repulsive force to another

Explanation:

A positive particle approaching another positive particle will repulse it.

According to coulomb's law "like charges repel one another and unlike charges attract".

A charge is an intrinsic property of any matter.

When like charges e.g positive and positive or negative and negative charges are in the vicinity of one another, they repel each other.

When unlike charges; positive and negative are brought together, they simply attract one another.

Therefore, we expect that a positive particle approaching another positive particle will repel one another.  

When a positive particle approaches another positive particle, the two particles repel or move away from each other.

In electrostatics we know that like charges repel while unlike charges attract. Therefore when we have two like charges, they simply move away from each other. This is known as repulsion of charges.

Hence, two positive charges approaching each other will simply move away and repel each other according to the laws of electrostatics.

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