Which value gives the number of particles in 1 mol of a substance?
6.02 x 1021
6.02 x 1022
6.02 x 1023
6.02 x 1024

Answer:

The HWA attacks eastern hemlock trees in forests and ornamental hemlock trees found in our residential landscaping. It feeds on the hemlock trees' young twigs by sucking the sap, causing their buds to die and needles to dry out and drop from the plant prematurely i think

hope i helped!!

Answer:

a) 7.22 × 10⁻¹⁹ J; b) 275 nm; c) 1.38× 10¹² electrons; d) 9.1 × 10⁻¹⁹ J

Explanation:

a) Minimum energy to eject photon

E = hf = 6.626× 10⁻³⁴ J·s × 1.09 × 10¹⁵ s⁻¹ = 7.22 × 10⁻¹⁹ J

b) Wavelength required

fλ = c

[tex]\lambda = \dfrac{c}{f } = \dfrac{2.998 \times 10^{8}\text{ m/s}}{1.09 \times 10^{15}\text{/s}} = 2.75 \times 10^{-7} \text{ m} = \textbf{275 nm}[/tex]

c) Electrons required

[tex]\text{No. of electrons} = 1.00 \times 10^{-6}\text{ J} \times \dfrac{\text{1 electron}}{7.22 \times 10^{-19}\text{ J}} = 1.38 \times 10^{12}\text{ electrons}[/tex]

d) Kinetic energy of electrons

a) Energy of photon

[tex]E = hf = \dfrac{\text{hc}}{\lambda} = \dfrac{6.626 \times 10^{-34} \text{ J$\cdot$ s}\times 2.998 \times 10^{8} \text{ m/s}}{122 \times 10^{-9}\text{ m}}= 1.63 \times 10^{-18} \text{ J}[/tex]

b) Maximum kinetic energy

The equation for the photoelectric effect is

hf = φ + KE, where  

φ = the work function of the metal — the minimum energy needed to eject an electron

KE = hf - φ = 1.63× 10⁻¹⁸ J - 7.22× 10⁻¹⁹ J = 9.1 × 10⁻¹⁹ J  

a. The energy of molybdenum to eject electron has been [tex]\rm \bold{7.22\;\times\;10^{-19}}\;J[/tex].

b. The wavelength of the radiation has been 275 nm.

c. The number of electrons present in [tex]\rm 1\;\mu J[/tex] energy has been [tex]\rm \bold{1.38\;\times\;10^1^2}[/tex].

d. The kinetic energy of the emitted electrons as been [tex]\rm \bold{9.1\;\times\;10^-^1^9\;J}[/tex].

The metal emits the energy when it returns from the excited state to ground state.

a. The energy (E) to eject electron has been given by:

[tex]E=h\nu[/tex]

Where, the value of constant, [tex]h=6.626\;\times\;10^{-34}\;\rm J.s[/tex]

The value of frequency has been given, [tex]\nu=\rm 1.09\;\times\;10^{15}\;s^{-1}[/tex]

Substituting the values for energy:

[tex]E=6.626\;\times\;10^{-34}\;\times\;1.09\;\times\;10^{15} \rm J\\\textit E=7.22\;\times\;10^{-19}\;J[/tex]

The energy of molybdenum to eject electron has been [tex]\rm \bold{7.22\;\times\;10^{-19}}\;J[/tex].

b. The wavelength ([tex]\lambda[/tex]) of the radiation has been given by:

[tex]\lambda=\dfrac{c}{\nu}[/tex]

Where, the speed of light, [tex]c=3\;\times\;\rm m/s[/tex]

The frequency has been given as, [tex]\nu=1.09\;\times\;10^{15}\;\rm s^-^1[/tex].

Substituting the values for wavelength:

[tex]\lambda=\dfrac{3\;\times\;10^8}{1.09\;\times\;10^{15}}\;\rm m\\ \lambda=2.75\;\times\;10^-^7\;m\\\lambda=275\;nm[/tex]

The wavelength of the radiation has been 275 nm.

c. The electrons ([tex]e^-[/tex]) burst out can be given as:

[tex]e^-=\dfrac{E}{E'}[/tex]

Where, the energy of radiations, [tex]E=1\;\times\;10^{-6}\;\rm J[/tex]

The energy of each electron has been calculated as, [tex]E'=7.22\;\times\;10^{-19}\;\rm J[/tex]

Substituting the values for number of electrons:

[tex]e^-=\dfrac{1\;\times\;10^-^6}{7.22\;\times\;10^-^1^9} \\e^-=1.38\;\times\;10^1^2[/tex]

The number of electrons present in [tex]\rm 1\;\mu J[/tex] energy has been [tex]\rm \bold{1.38\;\times\;10^1^2}[/tex].

d. The maximum kinetic energy (K.E.) of the radiation has been given as:

[tex]K.E.=\dfrac{hc}{\lambda} -E^'[/tex]

Where, the value of constant, [tex]h=6.626\;\times\;10^{-34}\;\rm J.s[/tex]

The speed of light, [tex]c=3\;\times\;\rm m/s[/tex]

The wavelength of the radiation, [tex]\lambda=122\;\times\;10^-^9\;\rm m[/tex]

Energy of each electron, [tex]E'=7.22\;\times\;10^{-19}\;\rm J[/tex]

Substituting the values, for kinetic energy:

[tex]K.E.=\dfrac{6.626\;\times\;10^{-34}\;\times\;3.0\;\times\;10^8}{122\;\times\;10^-^9}\;-\;7.22\;\times\;10^-^1^9\;\rm J \\\textit {K.E.}=9.1\;\times\;10^{-19}\;J[/tex]

The kinetic energy of the emitted electrons as been [tex]\rm \bold{9.1\;\times\;10^-^1^9\;J}[/tex].

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Answer:

Sn + 2H2O ==> Sn(OH)2 + 2H2

67.3 g Sn x 1 mol/119 g x 2 mol H2/mol Sn x 22.4 L/mole = answer in liters

Explanation:

Sn + 2H2O ==> Sn(OH)2 + 2H2

67.3 g Sn x 1 mol/119 g x 2 mol H2/mol Sn x 22.4 L/mole = answer in liters

The volume of hydrogen that will be produced from the reaction of 67.3 g of tin with excess water is 12.68 L

Mole = mass / molar mass

Mole of Sn = 67.3 / 119

Mole of Sn = 0.566 mole

Sn + 2H₂O —> Sn(OH)₂ + H₂

From the balanced equation above,

1 mole of Sn reacted to produce 1 mole of H₂.

Therefore,

0.566 mole of Sn will also react to produce 0.566 mole of H₂

Recall

1 mole of H₂ = 22.4 L at STP

Therefore,

0.566 mole of H₂ = 0.566 × 22.4

0.566 mole of H₂ = 12.68 L

Thus, 12.68 L of H₂ were obtained from the reaction.

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Answer:

The law of conservation of matter indicates that matter cannot be created nor destroyed.

So D Destroyed

We can represent the concentration of a material even when we don't know its molecular mass, since mass percentage and parts per million or a billion are just alternative ways of expressing the ratio of the mass of a solute to the mass of the solution.

The mass of a certain molecule is its molecular mass, which is expressed in daltons. Because they contain various isotopes of an element, multiple molecules of the same substance can have distinct molecular weights.

More solute can be dissolved in a given volume of solution to increase concentration, since doing so increases the mass of the solute. By allowing some of the solvent to evaporate, which reduces the volume of the solution, concentration can be increased.

The amount of a solute that is present in a specific amount of solvent or solution is known as the concentration of a solution. Controlling the stoichiometry of reactants for solution reactions requires knowledge of the solute concentration.

Thus, We can represent the concentration of a material even when we don't know its molecular mass.

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Answer:

The correct option is;

A.) 15 g to 18 g

Explanation:

The solubility of sulfur dioxide at room temperature = 94 g/L of water forming sulfurous acid as follows;

SO₂ + H₂O ⇄ HSO₃⁻ + H⁺

Which is a partial reversibly association with water molecules

Whereby 1 liter of water weighs 1 kg

9.4 gram of SO₂ will dissolve in 100 g of water at room temperature of 23 to 24°C

The solubility increases as the temperature reduces therefore as shown from the sulfur dioxide solubility chart we have;

At 10°C the solubility of SO₂ (g) is midway between 150 g to 200 g per kg of water

Therefore;

The solubility of SO₂ (g) is between 15 g to 18 g per 100 of water.

The mass of SO2 in the given solution should be an option a 15g to 18g.

Since the solubility of sulfur dioxide at room temperature = 94 g/L of water forming sulfurous acid likewise:

SO₂ + H₂O ⇄ HSO₃⁻ + H⁺

This represents the partial reversibly association along with water molecules

Here 1 liter of water weighs 1 kg

So we can say that

9.4 gram of SO₂ will dissolve in 100 g of water at room temperature of 23 to 24°C

Due to this, there is an increase in solubility this result in decrease in the temperature

Also, At 10°C the solubility of SO₂ (g) is midway between 150 g to 200 g per kg of water

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Answer:

The new volume of the balloon is [tex]346.5\ cm^3[/tex].

Explanation:

Initial volume of a balloon is 417 cm³

The temperature decreases from 278 K to 231 K.

It is required to find the new volume of the balloon if the pressure is constant pressure. At constant pressure, volume is directly proportional to the temperature. So,

[tex]V\propto T[/tex]

i.e.

[tex]\dfrac{V_1}{V_2}=\dfrac{T_1}{T_2}[/tex]

V₂ is final volume.

[tex]V_2=\dfrac{V_1T_2}{T_1}\\\\V_2=\dfrac{417\times 231}{278}\\\\V_2=346.5\ cm^3[/tex]

So, the new volume of the balloon is [tex]346.5\ cm^3[/tex].

Answer:

2HNO3+ Ba(OH)2 = Ba(NO3)2 + 2H2O

H3PO4 + Ca(OH)2 = Ca3(PO4)2 + 6H2O

Explanation:

2HNO3+ Ba(OH)2 = Ba(NO3)2 + 2H2O

H3PO4 + Ca(OH)2 = Ca3(PO4)2 + 6H2O

H+

O2-

OH-

Ba2+

Ca2+

NO3-

P 5+, 3+, 3-

H2O

Answer:

A

Explanation:

Hmm, so we have the following in the diagram

Pt(s)

Cl2(g)

Ag(s)

NaCl(aq)

AgNO3(aq)

Pt 2+, 4+, 6+  Though it states Pt is inert

Cl 2-

Ag 1+

Na 1+

NO3-

Anode definition: the positively charged electrode by which the electrons leave an electrical device.

Electrode definition: a conductor through which electricity enters or leaves an object, substance, or region.

Cations attracted to cathode pick up electrons

Anions attracted to anode release electrodes+

Reduction at Cathode (red cat gain of e)

Oxidation at Anode (ox anode loss of e)

So from the diagram we can see that the charge is being generated through the 2 metal plates.

So the answer is A, the anode material is Pt and the half reaction is 2Cl- = Cl2 + 2e-

Answer:

29.98kg

Explanation:

12.0 gallons * (3.78541178 liters/gallon) * (1000 mL/liter) * (0.66 g/mL) * (1 kg/1000 g) = 29.98 kg

29.98kg of gasoline fill a 12.0-gal gas tank

gasoline or gas or petrol a mixture of volatile, flammable liquid hydrocarbons which is derived from petroleum and used in many application like fuel in internal-combustion engines, solvent for oils and fats.

It is a by-product of the petroleum industry, used in automobile fuel due to its high energy of combustion and easily mix with air in a carburetor.

Gasoline is produced by distillation by separating the volatile substance, later on other designed process  yield of gasoline from crude oil by splitting large molecules into smaller ones by cracking method.

12.0 gallons * (3.78541178 liters/gallon) * (1000 mL/liter) * (0.66 g/mL) * (1 kg/1000 g) = 29.98 kg of gasoline fill the tank.

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Answer:

It is 1.76 tons under the weight limit.

Explanation:

12.65

-10.89

= 1.76

Answer:

Compounds formed from non-metals consist of molecules.

Explanation:

The atoms in a molecule are joined together by covalent bonds. These bonds form when atoms share pairs of electrons.

I hope I helped, please correct me if I'm wrong!

Considering the definition of covalent bond and molecules, compounds formed from only non-metals consist of particles called molecules.

But you have to know that the covalent bond is the chemical bond between atoms where electrons are shared, forming a molecule.

Covalent bonds are established between non-metallic elements, such as hydrogen H, oxygen O and chlorine Cl. These elements have many electrons in their outermost level (valence electrons) and have a tendency to gain electrons to acquire the stability of the electronic structure of noble gas.

The shared electron pair is common to the two atoms and holds them together.

In other words, a covalent bond is a type of chemical bond where two atoms of non-metallic elements join to form a molecule, where the atoms share pairs of electrons from their most superficial layer or valence layer to achieve stability in the molecule and thus complying with the octet rule.

In summary, compounds formed from only non-metals consist of particles called molecules.

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Answer:

C. element. oxygen is an element

Explanation:

oxygen is element #8

Answer:Ethyne

Explanation:

Ethyne is more commonly known under the trivial name acetylene. It is the simplest of the alkynes, consisting of two carbon atoms connected by a triple bond, leaving each carbon able to bond to one hydrogen atom. Since both carbon atoms are linear in shape, all four atoms lie in a straight line.

2-nonyne molecule is an alkyne. Hence, option B is correct.

Alkynes are groups of hydrocarbons that have the general formula of {Cn H2n - 2}. They have a triple carbon-to-carbon bond (C≡C) in their structure. Ethyne (HC≡CH) is the first member of the alkyne series.

Ethyne is more commonly known under the trivial name acetylene. It is the simplest of the alkynes, consisting of two carbon atoms connected by a triple bond, leaving each carbon able to bond to one hydrogen atom.

Since both carbon atoms are linear in shape, all four atoms lie in a straight line.

Hence, option B is correct.

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Answer:

they meen like what youve learned or like what youve been tonight....all that is work stuff you did for example school work.

Answer:

98.6%

Explanation:

First we put down the equation representing the decomposition of sodium bicarbonate.

2NaHCO3(s) ----> Na2CO3(s) + H2O(l) + CO2(g)

We can see from the data provided that the mass of sodium bicarbonate reacted is 3.01 g.

The number of moles of sodium bicarbonate reacted= mass of sodium bicarbonate/ molar mass of sodium bicarbonate

Molar mass of sodium bicarbonate= 84.007 g/mol

Number of moles of sodium bicarbonate=3.01 g/ 84.007 g/mol

Number of moles of sodium bicarbonate= 0.0358 moles

From the balanced reaction equation,

2 moles of sodium bicarbonate yields 1 mole of sodium carbonate

Hence 0.0358 moles of sodium bicarbonate yields 0.0358/2 = 0.0179 moles of sodium carbonate

Theoretical yield of sodium carbonate = number of moles of sodium carbonate × molar mass of sodium carbonate

Molar mass of sodium carbonate= 105.9888 g/mol

Theoretical yield of sodium carbonate= 0.0179 moles × 105.9888 g/mol

Theoretical yield of sodium carbonate= 1.897 g

Actual yield of sodium carbonate= 1.87 g

%yield of sodium carbonate= 1.87/1.897 ×100

%yield of sodium carbonate= 98.6%

Answer:

91kj/mol;no

Explanation:

Took this before I gotchu.

What is the ΔG, and will this reaction be spontaneous in the forward direction? 91 kJ/mol; no

Gibbs is a free number of power converters

In the active and frequent use of the Gibbs free energy change equation, ΔG is calculated from the fixed values ​​that scientists can measure: the enthalpy and entropy changes of the reaction, and the temperature at which the reaction occurs.

joules

measured in joules in SI) is the maximum amount of non-expansion work that can be extracted from a closed system (one that can exchange heat and work with its surroundings, but no matter) at fixed temperature and pressure. This maximum can be attained only in a completely reversible process.

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Answer:

C

Explanation:

C shows a mixture of CO2 and H2O, 2 compounds

Answer:

C

Explanation:

C shows a mixture of CO2 and H2O, 2 compounds

Answer:

D

The temperature.

Explanation:

Answer:

An acid dissociation constant, K a, (also known as acidity constant, or acid-ionization constant) is a quantitative measure of the strength of an acid in solution. It is the equilibrium constant for a chemical reaction ↽ − − ⇀ − + + known as dissociation in the context of acid–base reactions.

Explanation:

Answer: B. (No charge)

Explanation:

Protons have a positive charge, electrons have a negative charge.

Neutrons are neutral and therefore have no change.

Answer:

Explanation:

loss of habitat and contact with humans

Answer:

A

Explanation:

Loss of habitat and contact with humans contributed to the extinction of many large mammals.

Answer:

It's an homogeneous Mixture

hehe

Answer:

Explanation:

MgSO4  + 2NaOH -------> Mg(OH)2 + 2NaSO4

CuCl2   +2NaOH -------> Cu (OH)2 + 2Nacl

FeCl3 + 3NaOH  ----> Fe(OH)3  + 3NaCl

based on this can you try for the  FeSO4. similar to first reaction showed above

Answer:

-4

Explanation:

[tex]log 10^{-4} = -4 log 10[/tex]

log 10 = 1

Therefore -4 log 10 = -4 x 1 = -4

Answer:

Cause(s) the temperature of the surroundings to decrease. - 1. Endothermic reaction.

Cause(s) a change in the temperature of the surroundings. - 3. Both.

Cracking open a cold-pack. - 1. Endothermic reaction.

Burning Wood. - 2. Exothermic reaction.

Absorb(s) energy from the surroundings. - 1. Endothermic reaction.

Cause(s) the temperature of the surroundings to increase. - 2. Exothermic reaction.

Release(s) energy to the surroundings. - 2. Exothermic reaction.

Answer:

l only

Explanation:

The movement of substances in living cells can either require energy (active) or not (passive) depending on the direction of movement across concentration gradient. Naturally, substances tend to move down a concentration gradient i.e. difference in concentration, which is from a region of high concentration of water to a region of low concentration. This is the passive type of transport, which does not require energy input. Examples are osmosis, simple diffusion and facilitated diffusion.

However, another type of transport exists in which substances move against the concentration gradient i.e. from a less concentrated region to a more concentrated region. In this case, energy input in form of ATP is required for this kind of transport to occur. This transport is referred to as ACTIVE TRANSPORT. Hence, the answer is I only.

Answer:

C

Explanation:

Oxidation occurs at the anode. That means the element's oxidation number should increase. Mg has an oxidation number of 0, but Mg2+ has an oxidation number of 2, showing it was oxidized.

Answer:

Gravel >Sand>Silt>Clay

Explanation:

Sand, Clay, Gravel and Silt

Clay: all particles smaller than 0.002 mm

Silt: all particles within the size range of 0.002-0.05 mm;

Sand: all particles within the size range of  (2.0 mm - 0.05 mm)

Gravel particles are larger than sand, ranging in size from 4.75 mm to 75 mm

Going through the options, the correct option is;

Gravel >Sand>Silt>Clay