Answer:
The hydrogen spectrum is an important piece of evidence to show the quantized electronic structure of an atom. ... It results in the emission of electromagnetic radiation initiated by the energetically excited hydrogen atoms. The hydrogen emission spectrum comprises radiation of discrete frequencies.
The spectrum starts with red light, with a wavelength of 700 nanometers (7,000 angstroms), at the top. ... It spans the range of visible light colours, including orange and yellow and green, and ends at the bottom with blue and violet colours with a wavelength of 400 nm (4,000 angstroms).
Explanation:
Hydrogen molecules are first broken up into hydrogen atoms (hence the atomic hydrogen emission spectrum) and electrons are then promoted into higher energy levels. Suppose a particular electron is excited into the third energy level. It would tend to lose energy again by falling back down to a lower level.
The spectrum of the Sun appears as a continuous spectrum and is frequently represented as shown below. This type of spectrum is called an emission spectrum because what you are seeing is the direct radiation emitted by the source.
Answer: Dang I wish I wasn't on a school chrome, that way I can see the photo without it getting blocked *cries*
Explanation:
Answer:
7. A) I, II
; 8. D) 2.34e9 kJ
Step-by-step explanation:
7. Combustion of ethanol
I. The negative sign for ΔH shows that the reaction is exothermic.
II. The enthalpy change would be different if gaseous water were produced.
That's because it takes energy to convert liquid water to gaseous water, and this energy is included in the value of ΔH.
III. The reaction is a redox reaction, because
- Oxygen is reacting with a compound
- The oxidation number of C increases
- The oxidation number of O decreases.
IV. The products of the reaction occupy a smaller volume than the reactants, because 3 mol of gaseous reactant are forming 2 mol of gaseous product.
Therefore, only I and II are correct.
7. Hindenburg
Data:
V = 2.00 × 10⁸ L
p = 1.00 atm
T = 25.1 °C
ΔH = -286 kJ·mol⁻¹
Calculations:
(a) Convert temperature to kelvins
T = (25.1 + 273.15) K = 298.25 K
(b) Moles of hydrogen
Use the <em>Ideal Gas Law</em>:
pV = nRT
n = (pV)/(RT)
n = (1.00 × 2.00 × 10⁸)/(0.082 06 × 298.25) = 8.172 × 10⁶ mol
(c) Heat evolved
q = nΔH = 8.172 × 10⁶ × (-286) = -2.34 × 10⁹ kJ
The hydrogen in the Hindenburg released 2.34e9 kJ
.
Answer:
7 moles
Explanation:
Given data:
Moles of hydrogen = 7 mol
Moles of water formed = ?
Solution:
Chemical equation:
2H₂ + O₂ → 2H₂O
Now we will compare the moles of water with hydrogen from balance chemical equation:
H₂ : H₂O
2 : 2
7 : 7
So in the presence of excess oxygen and 7 moles of hydrogen seven number of moles of water produced.
