So there are three formulas that you must be aware of hen attempting these questions (by technicality, only two because the third is a transposition of the second).
These formulas are :
mole x L = # of atoms (where L = Avogadro's Constant)
mass / Mr = mole (where Mr = Molar Mass)
Mole x Mr = mass
So no we can easily ace these questions
1) a. 98.3 g of Hg
mass of Hg = 98.3g
Mr " " = 201 g / mol
mole =
= 0.489 mol
∴ # of atoms = 0.489 mol * (6.03 * 10²³)
= 2.95 * 10²³ atoms
c. 10.7g of Li
mass of Li = 10.7 g
Mr " " = 7 g / mol
thus mole =
= 1.529 mol
# of atoms = 1.529 mol * (6.03 * 10²³)
= 9.22 * 10²³
2) a. 6.84 g of C₁₂H₂₂O₁₁
mass of sucrose = 6.84 g
Mr " " = ∑ (Mr of each element * amount of each element's atom)
= ∑ [(12 * 12)+(1 * 12)+(16 * 11)] g / mol
= 342 g / mol
∴ mole of sucrose =
= 0.02 mol
c) 68.0g of NH<span>₃</span>
<span> mass of NH₃ = 68.0 g</span>
<span> Mr " " = [(14 * 1) + ( 1 * 3)] g / mol</span>
<span> ∴ mole of NH₃ = </span>
= 4 mol
3) a. 3.52 mol of Si
mole of Si = 3.52 mol
Mr " " = 28 g / mol
Mass = 3.52 mol * 28 g / mol
= 98.56 g
c. 0.550 mol of F₂
mol of F₂ = 0.55 mol
Mr " " = (19 * 2 ) g / mol
Mass = 0.55 mol * 38 g / mol
= 20.9 g
Hope I as clear in my answers and that they helped
Answer:
Yield of reaction is 76.7%
Explanation:
The reaction of salicylic acid with acetic anhydride to produce acetyl salicylic acid is 1:1. That means 1 mole of salicylic acid reacts with 1 mole of acetic anhydride (Acid is catalyst of reaction).
Moles of salicylic acid are:
And moles of acetic anhydride are:
As salicylic acid is limiting reactant, theoretical moles of acetyl salicylic acid are 0.04127mol. That means theoretical mass of acetyl salicylic acid is:
Thus, yield of reaction is:
<em>76.7%</em>
Answer:
True
Explanation:
In 1909 Ernest Rutherford proposed to Geiger and Marsden to conduct an experiment in which they would have to launch alpha particles from a radioactive source against a gold foil a few atoms thick.
The aim of the experiment was to corroborate Rutherford's idea that the particles would pass through the metal foil with little deviation.
Rutherford's interpretation of the experimental results gave rise to a new atomic model, and concluded that the mass of the atom was concentrated in a small region of positive charges that impeded the passage of alpha particles. He suggested a new model in which the atom had a nucleus or center in which the mass and the positive charge are concentrated, and that in the extra nuclear zone are the negatively charged electrons.
The primary difference between them is what they work with and what their goals are. Chemical engineers research and design production processes for things like food or gasoline while nuclear engineers focus on ways to harness and use radiation and nuclear energy.