1 mole of any substance contains 6.022 × 1023 particles.
⚛ 6.022 × 1023 is known as the Avogadro Number or Avogadro Constant and is given the symbol NA
N = n × NA
· N = number of particles in the substance
· n = amount of substance in moles (mol)
· NA = Avogardro Number = 6.022 × 10^23 particles mol-1
For H2O we have:
2 H at 1.0 each = 2.0 amu
1 O at 16.0 each = 16.0 amu
Total for H2O = 18.0 amu, or grams/mole
It takes 18 grams of H2O to obtain 1 mole, or 6.02 x 1023 molecules of water. Think about that before we answer the question. We have 25.0 grams of water, so we have more than one mole of water molecules. To find the exact number, divide the available mass (25.0g) by the molar mass (18.0g/mole). Watch how the units work out. The grams cancel and moles moves to the top, leaving moles of water. [g/(g/mole) = moles].
Here we have 25.0 g/(18.0g/mole) = 1.39 moles water (3 sig figs).
Multiply 1.39 moles times the definition of a mole to arrive at the actual number of water molecules:
1.39 (moles water) * 6.02 x 1023 molecules water/(mole water) = 8.36 x 1023 molecules water.
That's slightly above Avogadro's number, which is what we expected. Keeping the units in the calculations is annoying, I know, but it helps guide the operations and if you wind up with the unit desired, there is a good chance you've done the problem correctly.
N = n × (6.022 × 10^23)
1 grams H2O is equal to 0.055508435061792 mol.
Then 23 g of H2O is 1.2767 mol
To calculate the number of particles, N, in a substance:
N = n × NA
N = 1.2767 × (6.022 × 10^23)
N= 176.26
N=
Answer:
24 is the correct anwer
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Answer:
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Answer:
E) Intramolecular bond angles change
Explanation:
Infrared Radiation:
IR is electromagnetic radiations. The wavelength i.e. 700nm to 1000 mm of infrared is longer than invisible light and Its frequency is lower than light, that's why it is invisible to light.
- When IR radiation strike the molecule it absorbed by this molecule.
- This radiation used to identify and study chemicals.
- Infrared radiation interact with intra-bonds of the molecule.
- Bonds in the molecules have vibrational translational and rotational movements
- Due to these vibration, rotation and translation movement it absorb a radiation of specific frequency and wavelength
- These movements of bond are very small and absorbs radiations of very low frequency
- So when Infrared light or radiation absorbed the intra-bonds of the molecule get affected and angles of these bonds changes.
- As the frequency of the absorbed radiation matches the frequency of the bond that vibrates.
So
The correct option is option E
E) Intramolecular bond angles change
* Note:
it couldn't be option A as the frequency of IR is not enough to rotate a whole molecule
It Couldn't be option B as IR rations are electromagnetic radiation of longer wave length so it one can not see it with light so how it will glow a molecule
It also not could be the option C as for the excitation of electrons require much higher energy.
It also not the option D as nuclear magnetic spin is associated with nuclear magnetic radiation that are much different from IR.
Answer:
The balanced chemical equation:
Heat of combustion per gram of phenol is 32.454 kJ/g
Heat of combustion per gram of phenol is 3,050 kJ/mol
Explanation:
Heat capacity of calorimeter = C = 11.66 kJ/°C
Initial temperature of the calorimeter = 
Final temperature of the calorimeter = 
Heat absorbed by calorimeter = Q
Heat released during reaction = Q'
Q' = -Q ( law of conservation of energy)
Energy released on combustion of 1.800 grams of phenol = Q' = -(58.4166 kJ)
Heat of combustion per gram of phenol:
Molar mass of phenol = 94 g/mol
Heat of combustion per gram of phenol:
