Maybe this example could help you to understand this problem.
https://image.slidesharecdn.com/121howmanyatoms-091201144624-phpapp02/95/12-1-how-many-atoms-17-728....
Answer:
3.82 x 10²¹ molecules As₂O₃
Explanation:
To find the amount of molecules arsenic (III) oxide (As₂O₃), you need to (1) convert kg to lbs, then (2) convert g As₂O₃ to moles As₂O₃ (via molar mass), and then (3) convert moles to molecules (via Avogadro's number).
1 kilogram = 2.2 lb
Molar Mass (As₂O₃): 2(74.992 g/mol) + 3(15.998 g/mol)
Molar Mass (As₂O₃): 197.978 g/mol
Avogadro's Number:
6.022 x 10²³ molecules = 1 mole
0.0146 g As₂O₃ 1 kg 189 lb
------------------------ x --------------- x ------------------ x ................
1 kg 2.2 lb
1 mole 6.022 x 10²³ molecules
x ------------------ x --------------------------------------- = 3.82 x 10²¹ molecules As₂O₃
197.978 g 1 mole
Answer: (C)
The frequency increases as the wavelength decreases
Explanation:
The relation between the frequency and wavelength of a wave is
Frequency = 1 / Wavelength
The Frequency of electromagnetic wave is inversely proportional to the wavelength. So, as the frequency increases, the wavelength of the wave decreases and vise-versa.
The frequency of a wave is number of complete cycles passing a particular point per second. Its S.I unit is Hertz whereas the wavelength of a wave is the distance between two consecutive crest and trough in meters.
So, on increasing the frequency of a wave, there will be more number of the cycles of wave per second which will decrease the distance between the consecutive crest and trough i.e wavelength.
Answer:
blah blah blah blah blah blah blah blah blah blah blah
Ca +2
At -1
In +3
Sr +2
Ra +2
Fr +1
Ba +2
As -3
