What is the oxidation number of Si

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: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:

Question 1

Which type of bond describes the coming  together and sharing of two unpaired outer  electrons, one from each atom?

A. Single covalent bond.

Definition of single covalent bond:

A single covalent bond is when only one pair of electrons is shared between atoms.

Question 2

What is the name of this molecule (CO2) that  forms by burning of fuels and is one of the  gases that contributes to global  warming/climate change?

C. Carbon dioxide.

Answer:

103.00

Explanation:

1 mole of Glucose

6 C = 6 * 12 = 72 grams

12H = 12 * 1 = 12 grams

6O = 6 * 16 =96 grams

Total          = 180 grams

0.572 moles of Glucose

1 mol of glucose = 180 grams

0.572 mols of glucose = x

x = 0.572 * 180

x = 103.00 grams

Answer:

Marijuana

Opiates

Opioids

Explanation:

Answer:

C-Atoms of the reactants rearrange to form a new substance

Explanation:

Answer:

The answer is A.

Explanation:

B. is called a physical reaction

And C. is just a rearrangement.

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:

3 rd point will be the ans

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.

If the polar ice caps were to melt then it could lift the lid of a new carbon sink capable of soaking up carbon dioxide.

If all the ice protecting Antarctica, Greenland, and mountain glaciers around the sector were to melt, sea degrees might upward push about 70 meters (230 ft). the sea might cowl all of the coastal towns. And the land place would decrease considerably. but many cities, inclusive of Denver, might live to tell the tale.

Melting ice reasons more warming.

because they are darker in the shade, the ocean and land take in more incoming solar radiation and then launch the warmth to the environment. This reasons more global warming. in this way, melting ice causes more warming and so extra ice melts.

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Answer:

C. element. oxygen is an element

Explanation:

oxygen is element #8

Answer:

I have posted some questions I used when learning Graham's law of diffusion

Explanation:

i posted 16 questions

I hope it helps.

Answer:

-4

Explanation:

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

log 10 = 1

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

Answer:

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

So D Destroyed

Answer:

D

The temperature.

Explanation:

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:

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

Answer:

.7689 mol

15.516 g

Explanation:

Use the Ideal Gas Law, PV = nRT.

Make sure to use the correct ideal gas constant R. You can either put R in torr, or you can change the pressure to atm. I've just used the torr ideal gas constant.

481.1 torr * 29.9 L = n 62.364 LTorr/molK * 300 K

14384.89 = 18709.2n

n = .7689 mol

The molar mass of neon (remember that neon gas = Ne, it's not diatomic) is 20.18 g/mol from the periodic table.

.7689 mol * 20.18 g/mol = 15.516 g

Answer:

It is 1.76 tons under the weight limit.

Explanation:

12.65

-10.89

= 1.76

Answer: B. (No charge)

Explanation:

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

Neutrons are neutral and therefore have no change.

Answer:

Renewable energy require less overall maintenance than generators that use traditional fuel sources. Renewable energy has numerous health and environmental benefits.

Explanation:

Answer: 2.5 moles

2H2 + O2 = 2H2O

This implies that 2 moles of oxygen is needed to react with one mole of oxygen to form 2 moles of water

It also implies that

2 moles of hydrogen requires 32 grams of oxygen

? moles of hydrogen would require 40 g of oxygen

2 x 40/32 = 2.5 moles

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:

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:

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:

D. 0.079 mol

Explanation:

This question involving the number of moles of neon (Ne) gas can be solved using the ideal gas law, also called the general gas equation.

The formula for the general gas equation is:

PV = nRT

Where;

P = pressure (atm)

V = volume (Litres)

n = amount of substance (mol)

R = ideal gas constant

T = temperature (K)

In this question, P is given as 0.83atm, V = 2.2L, R = 0.0821 L.atm/mol.K, T= 283K, n = ?

We calculate 'n' by making it the subject of the formula i.e.

PV= nRT

Divide both sides by RT, we have;

n = PV/RT

Hence, we input our values

n = 0.83 × 2.2 / 0.0821 × 283

n= 1.826 / 23.2343

n = 0.07859

Hence, n is approximately 0.079 mol

Answer:

If the reaction is going from left to right it would be synthesis, if going right to left it would be decomposition.

Explanation:

Na2O (s) + 2CO2 (g) + H2O (g) = 2 NaHCO3 (s)

Left Side

Na = 2

O = 6

C = 2

H = 2

Right Side

Na = 2

O = 6

C = 2

H = 2

Ok so is balanced already, though initial equation in question had an error in regards to the left hand side the ) should have been an O.

Hmm

Na2O (s) + 2CO2 (g) + H2O (g) = 2 NaHCO3 (s)

If it was going from right to left would be decomposition

But going from left to right it would be synthesis

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:

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

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

3HCl + Fe(OH)3) = FeCl3 + 3H2O

Explanation:

H+

N3-

O2-

Ba2+

OH-

P 5+, 3+, 3-

Ca2+

Cl-

Fe  2+, 3+

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

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

3HCl + Fe(OH)3) = FeCl3 + 3H2O