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3 years ago

Interesting facts about coal

2 answers:

8 0

Coal will eventually run out as it is an non-renewable energy. these are when they cannot be reproduced to make more,unlike would as u can replant them to create trees

Delicious77 [7]3 years ago

7 0

Coal is made of carbon and also has more elements like hydrogen, oxygen, sulfur and nitrogen.
Coal starts as plant matter at the bottom of ocean/water. Eventually it is covered and buried by sediments where over a while, metamorphosis (a change in form) happens.
Coal is also one of the biggest, if not the largest, source of energy for the making of electricity.

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using the Bohr model for hydrogen: energy = hc/wavelength = 2.18 x 10^-18 Joules (1/nf2 - 1/ni2) N=15 to n=5

soldier1979 [14.2K]

Answer:

Energy lost is 7.63×10⁻²⁰J

Explanation:

Hello,

I think what the question is requesting is to calculate the energy difference when an excited electron drops from N = 15 to N = 5

E = hc/λ(1/n₂² - 1/n₁²)

n₁ = 15

n₂ = 5

hc/λ = 2.18×10⁻¹⁸J (according to the data)

E = 2.18×10⁻¹⁸ (1/n₂² - 1/n₁²)

E = 2.18×10⁻¹⁸ (1/15² - 1/5²)

E = 2.18×10⁻¹⁸ ×(-0.035)

E = -7.63×10⁻²⁰J

The energy lost is 7.63×10⁻²⁰J

Note : energy is lost / given off when the excited electron jumps from a higher energy level to a lower energy level

5 0

3 years ago

Calcuate the number of grams of solute in 453.9mL of 0.237 M calcium acetate

AysviL [449]

The number of grams : 17.082 g

<h3>Further explanation</h3>

Molarity shows the number of moles of solute in every 1 liter of solute or mmol in each ml of solution

$\large {\boxed {\bold {M ~ = ~ \dfrac {n} {V}}}$

Where

M = Molarity

n = Number of moles of solute

V = Volume of solution

453.9 mL of 0.237 M calcium acetate

$\tt mol=M\times V=0.237\times 0.4539=0.108$

mass

MW Ca(C₂H₃OO)₂ : 158,17 g/mol

$\tt mass=mol\times MW\\\\mass=0.108\times 158.17=17.082~g$

4 0

3 years ago

Automotive airbags inflate when a sample of sodium azide, NaN3, is very rapidly decomposed.

Kobotan [32]

Answer:

148 g

Explanation:

Step 1: Write the balanced equation for the decomposition of sodium azide

2 NaN₃ ⇒ 2 Na + 3 N₂

Step 2: Calculate the moles corresponding to 95.8 g of N₂

The molar mass of N₂ is 28.01 g/mol.

95.8 g × 1 mol/28.01 g = 3.42 mol

Step 3: Calculate the moles of NaN₃ needed to form 3.42 moles of N₂

The molar ratio of NaN₃ to N₂ is 2:3. The moles of NaN₃ needed are 2/3 × 3.42 mol = 2.28 mol.

Step 4: Calculate the mass corresponding to 2.28 moles of NaN₃

The molar mass of NaN₃ is 65.01 g/mol.

2.28 mol × 65.01 g/mol = 148 g

8 0

3 years ago

In the compound MgCl2MgCl2, the subscript 2 indicates that

MatroZZZ [7]

The subscript 2 indicate that there are two atoms of chlorine in the compound.

Explanation

Subscript in the chemical formula indicate the number of atoms of the element immediately before the subscript.

In MgCl₂ there are two(2) atoms of chlorine since Subscript 2 is immediately after chlorine.

3 0

3 years ago

Ammonia (NH3) is one of the most common chemicals produced in the united states. it is used to make fertilizer and other product

Greeley [361]

Answer:

a) N2 is the limiting reactant

b) 1215.9 grams NH3

c) 2283.6 grams H2

Explanation:

Step 1: Data given

Mass of N2 = 1000 grams

Molar mass N2 = 28 g/mol

Mass of H2 = 2500 grams

Molar mass H2 = 2.02 g/mol

Step 2: The balanced equation

N2(g) +3H2(g) → 2NH3(g)

Step 3: Calculate moles N2

Moles N2 = mass N2 / molar mass N2

Moles N2 = 1000 grams / 28.0 g/mol

Moles N2 = 35.7 moles

Step 4: Calculate moles H2

Moles H2 = 2500 grams / 2.02 g/mol

Moles H2 = 1237.6 moles

Step 5: Calculate limiting reactant

For 1 mol N2 we need 3 moles H2 to produce 2 moles NH3

N2 is the limiting reactant. There will be consumed 35.7 moles.

H2 is in excess. There will react 3*35.7 = 107.1 moles

There will remain 1237.6 - 107.1= 1130.5 moles H2

This is 1130.5 * 2.2 = 2283.6 grams H2

Step 6: Calculate moles NH3

For 1 mol N2 we need 3 moles H2 to produce 2 moles NH3

For 35.7 moles N2 we'll have 2*35.7 = 71.4 moles NH3

Step 7: Calculate mass NH3

Mass NH3 = moles NH3 * molar mass NH3

Mass NH3 = 71.4 moles * 17.03 g/mol

Mass NH3 = 1215.9 grams NH3

7 0

3 years ago