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3 years ago

Assuming you have 6.24 x 1014 electrons and the surface area of the pail is 0.2 m2, what is the charge density (C/m2)?

Chemistry

1 answer:

pentagon [3]3 years ago

4 0

Answer:

σ = 4.998 E-4 C/m²

Explanation:

1 Coulomb (C) ≡ 6.241509 E18 electrons (e)

∴ # elect = 6.24 E14 elect

charge (Q):

⇒ Q = (6.24 E14 elect)/( 1 C /6.241509 E18 elect) = 9.998 E-5 C

charge density (σ):

σ = Q/S

∴ surface area (S) = 0.2 m²

⇒ σ = ( 9.998 E-5 C ) / ( 0.2 m²)

⇒ σ = 4.998 E-4 C/m²

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Using the Bohr model, determine the energy, in joules, necessary to ionize a ground-state hydrogen atom. Show your calculations.

lord [1]

Answer:

The energy required to ionize the ground-state hydrogen atom is 2.18 x 10^-18 J or 13.6 eV.

Explanation:

To find the energy required to ionize ground-state hydrogen atom first we calculate the wavelength of photon required for this operation.

It is given by Bohr's Theory as:

1/λ = Rh (1/n1² - 1/n2²)

where,

λ = wavelength of photon

n1 = initial state = 1 (ground-state of hydrogen)

n2 = final state = ∞ (since, electron goes far away from atom after ionization)

Rh = Rhydberg's Constant = 1.097 x 10^7 /m

Therefore,

1/λ = (1.097 x 10^7 /m)(1/1² - 1/∞²)

λ = 9.115 x 10^-8 m = 91.15 nm

Now, for energy (E) we know that:

E = hc/λ

where,

h = Plank's Constant = 6.625 x 10^-34 J.s

c = speed of light = 3 x 10^8 m/s

Therefore,

E = (6.625 x 10^-34 J.s)(3 x 10^8 m/s)/(9.115 x 10^-8 m)

E = 2.18 x 10^-18 J

E = (2.18 x 10^-18 J)(1 eV/1.6 x 10^-19 J)

E = 13.6 eV

5 0

3 years ago

What are your main fears about this class (if any)?

netineya [11]

This is based on your personal opinion lol but ig you can say public speaking

8 0

3 years ago

Read 2 more answers

Consider the reaction of 19.0 g of zinc metal with excess silver nitrate to produce silver metal and zinc nitrate. The reaction

Alexeev081 [22]

Answer:

14.5 g silver

Explanation:

This is a problem using the stoichiometry of the reaction. First thing we need is the balanced equation:

Zn + 2 AgNO3 ----------------------- 2 Ag + Zn(NO3)2

We know that 14.6 g of Zn did not reacted, then we can calculate the amount of Zn reacted and do the calculation given the above reaction.

amount Zn reacted: 19.0 -14.6 g Zn = 4.4 g Zn

atomic weight of Zn: 65.37 g/mol

mol Zn reacted: 4.4 g Zn x ( 1 mol Zn/ 65.37 g Zn) = 0.067 mol Zn

We know from the balanced equation that moles of Ag are produced from 1 mol Zn therefore the mol of Ag produced are:

0.067 mol Zn x 2 mol Ag/ 1mol Zn = 0.135 mol Ag

and the mass of silver then will be given by multiplying by the atomic weight of silver:

0.135 mol Ag x 107.9 g/mol = 14.5 g Ag

4 0

3 years ago

(chem) which is more concentrated: 45.0 grams of HCOOH dissolved in 189 mL of water or 1.5 moles of CH↓2COOH dissolved in twice

Liula [17]

Answer:

CH3COOH would be more concentrated

Explanation:

The higher the concentration value, the more concentrated it is.

The relationship between concentration, moles and volume is given by the equation;

Concentration = No of moles / Volume

5.0 grams of HCOOH dissolved in 189 mL of water

Number of moles = Mass / Molar mass = 5 / 46.03 = 0.1086 mol

Concentration = 0.1086 / 0.189 = 0.5746 mol/L

1.5 moles of CH3COOH dissolved in twice as much water

Volume = 2 * 189 = 378 ml = 0.378 L

Concentration = 1.5 / 0.378 = 3.9683 mol/L

Comparing both concentration values;

CH3COOH would be more concentrated

6 0

2 years ago

Calculate the mass of khc8h4o4 that reacts with 15 ml of the naoh solution

dlinn [17]

The balanced chemical reaction would be:

KHC8H4O4 (aq) + NaOH (aq) → NaKC8H4O4 (aq) + H2O.

The concentration of the NaOH is equal 0.1 M. We use this and the volume given above to determine the mass of KHC8H4O4. We do as follows:

0.1 mol / L NaOH (.015 L) ( 1 mol KHC8H4O4 / 1 mol NaOH) (204 g / 1 mol) = 0.306 g KHC8H4O4

6 0

3 years ago