True or False: A neutrally charged atom has an equal number of protons and electrons.

Kinetic energy liberated is 10.2 eV from the equation of photoelectric effect

What is photoelectric effect?

Photoelectric effect is a phenomenon in which electrons are ejected from the surface of a metal when light is incident on it.

What is the kinetic energy?

According to Einstein's photoelectric equation, we know that kinetic energy is the difference between the energy of incident photon and the work function of the metal.

KE = E - Wo

KE = kinetic energy

E = energy of the photon

Wo = work function

Now we know that

E = hf

h = Plank's constant (6.6 × 10-³⁴ )

f = frequency

E = 6.6 × 10-³⁴ × 3.62 × 10¹⁵

= 2.39 × 10-¹⁸J or 14.9 eV

1 eV = 1.6 × 10-¹⁹ J

Substituting

KE = 14.9eV - 4.7eV

KE = 10.2eV

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Significant figures are the number of digits in a number. To count the significant figures we must take into account that the zeros before the digit should not be counted, but the intermediate zeros or after the digit should be counted.

Now, when we do the two-digit division, the significant figures of the quotient will be equal to those of the digit with the fewest number of significant figures. Let's see what are the figures of the terms of the division and the final result:

We see that the quotient of the division is 0.746899..., but we have to write the answer only with 3 significant figures. If the number after the last figure to which we want to approximate is greater than 5, we must add 1 to the last figure, so the result will be: 0.747.

Answer: 0.747

ANSWER

The arrow will be shifted to the right (OPTION B)

EXPLANATION:

Firstly, we need to write out the chemical reaction equation

From the reaction above, you will see that heat is one of the products, this means that the reaction is n exothermic reaction.

An exothermic reaction is a type of reaction in which heat is released to its surroundings.

In an exothermic reaction, a decrease in temperature will shift the equilibrium to the right

when exposed to an etchant, the atoms at the grain boundary dissolve at a greater rate than those within grains. this is because the atoms at the boundary : Have a higher state of energy

Etchant is an acid or corrosive that is used to etch. Etching is traditionally the process of cutting into the unprotected parts of a metal surface with a strong acid or mordant to create an intaglio design in the metal.

A grain boundary in materials science is the interface between two grains, or crystallites, in a polycrystalline material. Grain boundaries are 2D defects in the crystal structure that tend to reduce the material's electrical and thermal conductivity.

Most grain boundaries are preferred sites for the initiation of corrosion and the precipitation of new phases from the solid. Grain boundaries, on the other hand, disturb the movement of dislocations through a material, so limiting crystallite size is a pervasive way to improve a material's strength.

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Answer: it would cause a serious shock

Explanation:

It is needed 1498.25 g of SiO2.

- From the chemical equation, we know that to produce 40.10 g of SiC, it is needed 60.08 g of SiO2 and 36.033 g of C (because in the reaction there are 3 moles of C).

- Calculating we obtain that:

So, it is needed 1498.25 g of SiO2. This can be expressed as 1.50x10^3 g.

a) Data:

F = 600 N

t = 1.5 s

The equation for Impulse:

Impulse = I = F x t,

then the change in momentum: pf - pi

Impulse and the change in momentum are related like this:

pf - pi = I = F x t = 600 N x 1.5 s = 900 N.s

Therefore the change in momentum: pf-pi = 900 N.s

b) Velocity (t) = initial velocity + a x t

We can assume initial velocity = 0 m/s

From F = m x a = mass x acceleration, we clear "a",

m = 275 g = 0.275 kg (1 kg = 1000 g)

Then, F/m = a => 600 N/0.275 kg = 2182 m/s^2

Velocity (t) = 0 + 2182 m/s^2 x 1.5 s = 3273 m/s

Velocity = 3273 m/s

Answer: If a pinch of mercury is consumed you will die from it so using a mercury thermometer is very unsafe if its breaks and a child consumes that mercury.

Explanation:

Don't use one

If the glass breaks and the mercury is not properly cleaned up, the little silvery ball within a mercury thermometer might be hazardous. As the mercury evaporates, it may pollute the air around and turn dangerous to both people and animals.

Children that have been exposed to mercury have lower IQs, hearing impairments, and worse coordination.

Long-term exposure worsens and exacerbates symptoms, which may lead to personality changes or even coma.

Mercury thermometers can be replaced by a number of things:

These non-mercury fever thermometers are significantly safer and equally accurate as mercury thermometers.

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We are told that we must assume that the gas behaves as an ideal gas in order to apply the following equation:

Where,

P is the pressure of the gas, 0.9801atm

V is the volume of the gas, 13mL=0.013L

R is a constant, 0.08206 atm-L/mol-K

T is the temperature of the gas, 22°C=295.15K

Now, we will clear the moles of the gas, n and we replace the known data:

now, to have the mass of the gas, we will use the molar mass. In this case, the molar mass of O2=31.999g/mol

The grams of O2 produced in the reaction are 1.7x10^-2 g of O2

The magnification will be 9x.

A telescope is a device which is used to watch the objects far away in the space. In this device, different lenses are used and a reflecting surface is also used.

This light is reflected on a large mirror surface and the telescope has eyepiece which helps to see the object.

The magnification is the function between the focal length and the distance through which object is to be viewed.

Here,

The magnification will be 450/ 50 = 9x

Therefore the magnification of the eyepiece will be 9x.

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Explanation

To find the molar mass of sulfur dihydride, you will need to find the sum of all the atomic masses making up sulfur dihydride.

sulfur dihydride is H2S.

Atomic mass of H = 1,00784 u

Atomic mass of S = 32,065 u

Molar mass = (1.00784 x 2) + 32,065 = 34.081 g/mol

Answer

34.081 g/mol

In order to answer this question we will use again the Avogadro's number, but now we are going to find out how many moles we have in 2.19*10^22 molecules of NaF

1 mol = 6.02*10^23 molecules

x moles = 2.19*10^22 molecules

x = 0.04 moles of NaF

Now that we have the number of moles, to find the mass we will need the molar mass of NaF, which is 42 g/mol, this means that for every mol of NaF, we will have 42 grams of it

42 g = 1 mol

x grams = 0.04 moles

x = 1.68 grams of Sodium fluoride, NaF

Answer:

Explanation:

Hi  Kiwi,   Atoms are very stable,  it takes a gigantic amount of energy to break them up.  Compounds (molecules) take far far less, and are rearranged all the time.   valence electrons are the electric force that stick molecules together.  it's relatively small, the energy to break up molecules.

Answer:

6.37g of iron are produced.

Explanation:

1st) From the balanced reaction we know that 1 mole of Fe2O3 reacts with 3 moles of H2 to produce 2 moles of Fe and 3 moles of H2O.

With the molar mass of Fe2O3 (160g/mol) and H2 (2g/mol) we can convert the moles to grams:

- Fe2O3 conversion: 1 mole is equal to 160g, so here it is not necessary to calculate the conversion.

- H2 conversion:

So, from the balanced reaction we know that 160g of Fe2O3 react with 6g of H2.

2nd) Now we have to find out which compound is the limiting reactant and which compound is the excess reactant, using the 9.1g and 16.8g given in the exercise:

So, the 9.1g of Fe2O3 will need 0.34g of H2 to react properly, but we have 16.8g of H2 so H2 is the excess reactant and Fe2O3 is the limiting reactant.

3rd) Using the limiting reactant, we can calculate the grams of iron that are produced.

It is necessary to use the molar mass of iron (56g/mol) to convert the 2 moles in the reaction to grams (2 Fe moles = 112g).

Finally, 6.37g of iron are produced.

Answer:

sulfur and water

Explanation:

sulfur + water --> sulfuric acid

^ reactants. ^ product

If a change in the ecosystem caused the number of species to stay the same and the total number of individuals to increase then The biodiversity index would increase".

An ecosystem's efficiency (the quantity of food energy transformed into biomass) and the quality of its services (which frequently include preserving the soil, cleaning the water that runs through it, as well as providing food and shade, etc.) both decrease with declining biodiversity.

An ecosystem's efficiency (the quantity of food energy transformed into biomass) as well as the quality of its services (which frequently include preserving the soil, cleaning the water which flows through it, as well as providing food as well as shade, etc.) both decrease with declining biodiversity.

Therefore, the correct option will be (4)

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iii. True. The existence of a vacancy in a crystal decreases the energy of the material.

One of the scientific disciplines called crystallography examines how the atoms in a solid crystal are arranged. When molecules are linked together in a regular way, these crystals are created.

The mechanical, physical, and optical properties of a material can alter when crystal flaws are present. The strength of the material can be impacted by a flaw.

An irregularity in the atoms' regular geometrical arrangement within a crystalline material is referred to as a crystal defect. These flaws are caused by the solid being deformed, cooling quickly from a high temperature, or being exposed to high-energy radiation (such as X-rays or neutrons). because the vacancy cause defects and the crystal structure is disturbed this causes a decrease in energy.

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The speed of the particles rises with the temperature of the solid, liquid, or gas. The particles slow down with decreasing temperature.

A liquid can turn into a solid if it is cooled down far enough.

The average kinetic energy of the molecules falls as a liquid cools.

The liquid eventually turns into a solid when the quantity of heat removed is sufficient to cause the molecules to be attracted to one another.

Freezing is the process of transitioning from a liquid to a solid.

It loses thermal energy when the liquid cools. Its constituent particles therefore decelerate down and converge.

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i,ii&iii only the alkanes forms 3-bromo-3-methylpentane as the major product when it's react with hbr.

What is alkanes forms?

Alkanes are the series of a  compounds that is contain carbon and hydrogen atoms of the  with single covalently bonds. Theses are knowns as saturated if  hydrocarbons. This group of the  compounds consists of a  carbon and hydrogen and  atoms with single covalent bonds. Also it is comprises a homologous series of  having a molecular formula of CnH2n+2.

Sol- Which of the following is the issue this? After adding HBR, Elkins produces three bromo three metal paintings as the main output. So allow me to simply write an equation, okay? I'm writing right here. What will this compound be when HBR is reacted? We'll be receiving a substance similar to this. Okay, my name is B. R. Once more, we are processing with H to the right.

That's it. Thus, organic compounds will now be observed. It's a beard. Right? Therefore, you can add B. R. as a further point here. We will arrive soon. Yes, once more, the beard is what makes this strange. So once more, we will be able to return home in this manner. The fact that we are getting the same compound means that the main component of this is three Bromo three metal. The fact that they all have the same product and option is therefore true. Right? No further inquiry is made regarding which of the following cardboard signs will experience Metal shift at 1 and 2. Right? Therefore, none of them have ever been the right response because none of them will experience a 12 m shift.

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The Ka of an acid indicates how strong this acid is. This means that greater acidity constant Ka corresponds to stronger acids, and lower Ka corresponds to weakest acids. I the example the acetic acid (CH3COOH) has an acidity constant 6 order of magnitude greater than the HCO3- there fore acetic acid is stronger than HCO3-

A substance's melting point decreases when impurities are present, but its boiling point increases.

What is melting point?

The temperature at which a certain solid material melts, or transitions from a solid state to a liquid, is known as the melting point.

Explanation:

Yes. Both the melting and boiling points are affected by impurities. Consider the example of water.

Pure water reaches its boiling point at 100 degrees Celsius. However, if the water has contaminants, the boiling point will be a little bit higher than 100 degrees Celsius.

A compound's melting point will be reduced by a few degrees and its melting point temperature range will be expanded by the presence of even a modest quantity of impurity. It is simpler to overcome the intermolecular interactions between the molecules since the impurity results in defects in the crystalline lattice.

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The process of a liquid becoming a gas is called boiling (or vapourization) and the process of a solid becoming a liquid is called melting.

Vaporization is the process of converting a liquid into a gas. It is also called evaporation. Since we know that the particles of a gas are moving faster than those of a liquid, an input of energy must be required for a liquid to become a gas.

Melting is a physical process that results in the phase transition of a substance from a solid to a liquid. During melting, the energy goes exclusively to changing the phase of a substance; it does not go into changing the temperature of a substance. Hence melting is an isothermal process because a substance stays at the same temperature.

Example 1: Industrially, salt is recovered from seawater by the process of vaporization. Wet clothes are dried up due to the process of vaporization. The process is used in many industrial processes for separating the components of a mixture.

Example 2: Ice to water - Ice melts back into the water when it is left out at temperatures above the freezing point of 32 degrees. Rocks to lava - Rocks in volcanoes can be heated until they are molten lava. Metal to molten liquid - Metals such as steel and bronze can be molten down.

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The elements that fit each of the descriptions from their properties in the periodic table are;

a) Cu

b) As

c) Xe

d) Br

e)Cs

f) I

g) O

h) Be

The periodic table has to do with the arrangement of the elements in the order of increasing atomic numbers of the elements. As such, the elements are known to have properties that differ as you move from left to right in the periodic table.

Now, the elements that are found in the same group in the periodic table are known to have similar reactivities while the elements that are found in the same period in the table have the same number of shells. The non metallic properties of the elements tend to increase as we move across a period.

Looking at the periodic table, we can be able to answer the question as they have been seen above. These questions ask about the relative positions of elements in the periodic table.

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A photon has energy of 1.8 x 10⁻¹² Jules. The wavelength of this photon is 11.04 × 10⁻¹⁴ m.

Given that :

Energy of the photon : 1.8 × 10⁻¹² J

Energy of the photon is given by the formula :

E = h v

where,

E = energy of photon

h = Planck constant = 6.626 × 10⁻³⁴ J.s

v = frequency of photon

frequency of photon is given as :

v = c / λ

therefore ,

E = h c / λ

λ = h c /E

c = speed of light = 3 × 10⁸ m/s

λ = (6.626 × 10⁻³⁴ J.s  × 3 × 10⁸ m/s) /  1.8 × 10⁻¹² J

λ = 11.04 × 10⁻¹⁴ m

Thus, A photon has energy of 1.8 x 10⁻¹² Jules. The wavelength of this photon is 11.04 × 10⁻¹⁴ m.

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Answer:

in an ionic bond, atoms lose valence electrons and become positively charged

Explanation:

To clarify, the atom that loses the electrons becomes a positively charged ion (cation), and the atom that gains them becomes a negatively charged ion (anion).

Answer:

Forests are a renewable resource

Answer: B. Forests

Explanation:

This is because, as part of its biological cycle, carbon is taken up by trees and becomes forest biomass that eventually dies, decays, and releases carbon that is in turn taken back up by renewed forest growth.

Here ya go! Sorry this took so long, editing is hard