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4 years ago

Consider the model of the nitrogen atom.

Chemistry

2 answers:

IRINA_888 [86]4 years ago

8 0

Answer:

Explanation:

liq [111]4 years ago

5 0

Answer:

1s2 2s2 2p3

Explanation:

we know that the number of electrons in an atom is equal to number of protons. So the number of electrons here is 7.

Using Moller chart, the electronic configuration is writen by the electrons first enterring into 1s then into 2s after 2p. The s orbital accomodates maximum of 2 electrons.

∴ for atomic no. 7 nitrogen atom, electronic configuration is 1s2 2s2 2p3.

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it takes 513 kj to remove a mole of electrons from the atoms at the surface of a piece of metal. how much energy does it take to

schepotkina [342]

Answer:

The right solution is " $8.5\times 10^{-19} \ joule$ ".

Explanation:

As we know,

1 mole electron = $6.023\times 10^{23} \ no. \ of \ electrons$

Total energy = $513 \ KJ$

= $513\times 1000 \ joule$

For single electron,

The amount of energy will be:

= $\frac{513\times 1000}{(6.023\times 10^{23})}$

= $8.5\times 10^{-19} \ joule$

8 0

3 years ago

Calculate the volume in mL of 0.279 M Ca(OH)2 needed to neutralize 24.5 mL of 0.390 M H3PO4 in a titration.

Vsevolod [243]

The volume of the 0.279 M Ca(OH)₂ solution required to neutralize 24.5 mL of 0.390 M H₃PO₄ is 51.4 mL

<h3>Balanced equation </h3>

2H₃PO₄ + 3Ca(OH)₂ —> Ca₃(PO₄)₂ + 6H₂O

From the balanced equation above,

The mole ratio of the acid, H₃PO₄ (nA) = 2
The mole ratio of the base, Ca(OH)₂ (nB) = 3

<h3>How to determine the volume of Ca(OH)₂ </h3>

Molarity of acid, H₃PO₄ (Ma) = 0.390 M
Volume of acid, H₃PO₄ (Va) = 24.5 mL
Molarity of base, Ca(OH)₂ (Mb) = 0.279 M

Volume of base, Ca(OH)₂ (Vb) =?

MaVa / MbVb = nA / nB

(0.39 × 24.5) / (0.279 × Vb) = 2/3

9.555 / (0.279 × Vb) = 2/3

Cross multiply

2 × 0.279 × Vb = 9.555 × 3

0.558 × Vb = 28.665

Divide both side by 0.558

Vb = 28.665 / 0.558

Vb = 51.4 mL

Thus, the volume of the Ca(OH)₂ solution needed is 51.4 mL

Learn more about titration:

brainly.com/question/14356286

5 0

2 years ago

Olympic cyclists fill their tires with helium to make them lighter. Assume that the volume of the tire is 860 mL , that it is fi

nata0808 [166]

Answer:

a) the mass of air = 8.24 grams

b) the mass of helium = 1.14 grams

c) the mass difference = 7.10 grams

Explanation:

Step 1: Data given

Volume of the tire = 860 mL

Total pressure = 120 psi

Temperature = 26°C

molar mass of air = 28.8 g/mol

Step 2: Convert psi to atm

(

120 psi) (1 atm / 14.7 psi) = 8.163

Step 4: Calculate moles

PV = nRT

⇒ with P = the pressure = 8.163 atm

⇒ with V = the volume = 860 mL = 0.860 L

⇒ with n = the number of moles = TO BE DETERMINED

⇒ with R = the universal gas constant = 0.08206 L*atm/K*mol

⇒ with T = the temperature = 26 °C = 299 Kelvin

n = (8163*0.860)/(0.08206*299)

n = 0.2861 moles of gas

Step 5: Calculate the mass of air in an air-filled tire.

Mass = moles * molar mass

Mass = (0.2861 moles of gas) (28.8 g/mol)

Mass = 8.24 grams

Step 6: Calculate the mass of helium in a helium- filled tire.

mass of helium = 0.2861 moles of gas * 4 g/mol)

mass of helium = 1.14 grams

Step 7: What is the mass difference between the two?

Δmass= 8.24 grams - 1.14 grams

Δmass= 7.10 grams

8 0

4 years ago

To answer this question, you will need to write the balanced equation and set up a BCA table. Using appropriate rounding rules,

Elenna [48]

Water decomposes when electrolyzed to produce hydrogen and oxygen gas. If 2.5 grams of water were decomposed 1.04 grams of oxygen will be formed.

BCA table:

2 $H_{2}$ O ⇒ $H_{2}$ + $O_{2}$

B 0.13 0 + 0

C -0.13 0.065 + 0.065

A 0 0.065

Explanation:

Balanced equation for water decomposition into hydrogen and oxygen gases

2 $H_{2}$ O ⇒ $H_{2}$ + $O_{2}$

B 0.13 0 + 0

C -0.13 0.065 + 0.065

A 0 0.065

Number of moles of water = $\frac{mass}{atomic mass of 1 mole}$

mass = 2.5 grams

atomic mass= 18 grams

number of moles can be known by putting the values in the formula,

n = $\frac{2.5}{18}$

= 0.13 moles

2 moles of water gives one mole of oxygen on decomposition

so, 0.13 moles of water will give x moles of oxygen on decompsition

$\frac{1}{2}$ = $\frac{x}{0.13}$

x = 0.065 moles of oxygen will be formed.

moles to gram will be calculated as

mass =number of moles x atomic mass

= 0.065 x 16

= 1.04 grams of oxygen.

7 0

4 years ago

Calculate the wavelength of light with a frequency of 1.89 x 1018 Hz.

Charra [1.4K]

Which sentence from "Black Hole Beginnings" contains a cause-and-effect relationship?
More matter mounts up on the outside, increasing the pressure on the inside.
Instead it is a dramatic melding, or blending, of atoms, called nuclear fusion.
Each atom has its own tiny center, or nucleus.
Surrounding each nucleus is an electrical force field..

6 0

4 years ago