Answer:
81.59%
Explanation:
First we <u>convert 107.50 g of NH₃ into moles</u>, using its <em>molar mass</em>:
- 107.50 g NH₃ ÷ 17 g/mol = 6.32 mol NH₃
Now we <u>calculate how many moles of NO would have been formed by the complete reaction of 6.32 moles of NH₃</u>:
- 6.32 mol NH₃ *
= 6.32 mol NO
Then we <u>convert 6.32 moles of NO to grams</u>, using its <em>molar mass</em>:
- 6.32 mol NO * 30 g/mol = 189.60 g NO
Finally we <u>calculate the percent yield</u>:
- 154.70 g / 189.60 g * 100% = 81.59%
Answer:
Here's what I get.
Explanation:
(b) Wavenumber and wavelength
The wavenumber is the distance over which a cycle repeats, that is, it is the number of waves in a unit distance.
Thus, if λ = 3 µm,
(a) Wavenumber and frequency
Since
λ = c/f and 1/λ = f/c
the relation between wavenumber and frequency is
Thus, if f = 90 THz
(c) Units
(i) Frequency
The units are s⁻¹ or Hz.
(ii) Wavelength
The SI base unit is metres, but infrared wavelengths are usually measured in micrometres (roughly 2.5 µm to 20 µm).
(iii) Wavenumber
The SI base unit is m⁻¹, but infrared wavenumbers are usually measured in cm⁻¹ (roughly 4000 cm⁻¹ to 500 cm⁻¹).
Answer/Explanation:
We cannot see the passage, but SAD stands for Seasonal Affective Disorder. SAD is a type of depressive disorder related to lack of light, and therefore changes with the seasons. It is a severe version of the "winter blues"
In the winter months, where the days are shorter, individuals who suffer from SAD suffer from mood changes. They get depressed, have a reduction in energy levels, and withdraw socially. They may also gain weight. This causes problems with relationships, work, and school.
Since SAD is linked to light, SAD is likely more common in the Northern areas of the United States, where winter days are shorter.
Answer:
There were originally 8 atoms of Potassium-40.
Explanation:
The half-life of a radioactive material is the time taken for half the original material to decay or the time required for a quantity of the radioactive substance to reduce to half of its initial value.
If the original material formed without any Argon-40, it means that the atoms originally present were Potassium-40 atoms.
Presently, there are 7 Argon-40 atoms for every 1 of Potassium-40, we can deduce the number of half-lifes the Potassium-40 has undergone as follows :
After one half-life, (1/2) there will be one Potassium-40 atom for every Argon-40 atom.
After a second half life, 1/2 × 1/2 = 1/4: there will be one Potassium-40 atom for every three atoms of Argon-40.
After a third half-life, 1/4 × 1/2 = 1/8: there will be one Potassium-40 atom for every 7 atoms of Argon-40.
Since there are 1/8 atoms of Potassium-40 presently, there were originally 8 atoms of Potassium-40.
