What is 25x3.08?? Help me plz
2 answers:
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1.326 grams of NH3 are required to produce 4.65 g of HF.
Step-by-step explanation:
Balanced chemical reaction is written first to know the number of moles taking part in original reaction.
NH3 +3 F2 ⇒3 HF + NF3
Given:
mass of HF = 4.65
First the number of moles of HF in 4.65 grams is calculated by using the formula:
number of moles (n) =
atomic mass of HF = 20 grams/mole
putting the values in the above equation number of moles can be found.
n =
= 0.235 moles of HF are given.
From the equation it can be said that:
1 mole of NH3 reacts to form 3 moles of HF
so, x moles of NH3 would react to form 0.235 moles of HF
=
3x = 0.235
x =
x = 0.078 moles of NH3 is required.
The moles are converted to mass by applying the formula:
mass = atomic mass X number of moles (atomic mass of NH3 = 17 grams/mole)
putting the values in the formula
mass = 17 X 0.078
mass = 1.326 grams
Answer:
so, the figure here is a cylinder with a semi sphere on the top, we know the height of whole structure, and the radius of the semi sphere, which is the same as the radius of the cylinder (you can see it because the radius of the semisphere is constant, and you can thin on it as half a sphere over a cylinder).
First, the cylinder will be the structure without the semi sphere, so his height will be te total height minus the radius of the semi sphere, which is 0.9μm.
so now we know the height and the radius of the cylinder, the surface or the sides of it is 2*3.14*r*h = 2*3.14*0.9μm*0.1μm = 0.5662.