Hi!
Answer:
The change in temperature.
Explanation:
Snow forms at 0 °C, when water vapor converts directly into solid ice crystals. Sleet forms when raindrops fall through a layer of air colder than 0 °C. This means that from the time it was snowing to the time it started sleeting the air has gotten warmer but one layer of air stayed cold, hence the formation of sleet. Freezing rain is rain that freezes when it hits a cold surface. This means that from the time it was sleeting to the time there was freezing rain the air had completely warmed and is now above 0 °C but the ground and all other surfaces are still cold.
I hope this helps, as this happens all the time where I live! :)
Answer:
Explanation:
From the given information:
Camphor may be reduced as readily in the presence of sodium borohydride(NaHB4). The resulting compound which is stereoselective requires 1 mole of sodium borohydride (NaHB4) to reduce 1 mole of camphor in this reaction. The reaction is shown below.
Through the reduction process of camphor, the reducing agent can reach the carbonyl face with a one-carbon linkage. The product stereoisomer is known as borneol.
If the molecular weight of camphor = 152.24 g/mol
and it mass = 200 mg
The its no of moles = 200 mg/ 152.24 g/mol
= 1.3137 mmol
Now the amount of the required mmol for NaBH4 to be consumed in the reaction = 5.2 × 1.3137 mmol
= 6.831 mmol
since the molar mass of NaBH4 = 37.83 g/mol
Then, using the same formula:
No of moles = mass/molar mass
mass = No of moles × molar mass
mass = 6.831 mmol × 37.83 g/mol
mass of NaBH4 used = 258.42 mg
159.3 g
mol= mass (g)/ molecular weight (g/mol)
volume of Ni = 25 nL = 25 x 10⁻⁹ L
mol Ni = 25 x 10⁻⁹ L x 1.25 mol/L = 3.125 x 10⁻⁸
mass = mol x Ar Ni
mass = 3.125 x 10⁻⁸ x 59 g/mol
mass = 1.84 x 10⁻⁶ g = 1.84 μg