3.47 x atoms of gold have mass of 113.44 grams.
Explanation:
Data given:
number of atoms of gold = 3.47 x
mass of the gold in given number of atoms = ?
atomic mass of gold =196.96 grams/mole
Avagadro's number = 6.022 X
from the relation,
1 mole of element contains 6.022 x atoms.
so no of moles of gold given =
0.57 moles of gold.
from the relation:
number of moles =
rearranging the equation,
mass = number of moles x atomic mass
mass = 0.57 x 196.96
mass = 113.44 grams
thus, 3.47 x atoms of gold have mass of 113.44 grams
Answer:
THE HALF LIFE OF THE RADIOACTIVE PHOSPHORUS-32 IS 1.15 DAYS.
Explanation:
Half life is the time required for half of a given sample of a radioactive substance to decay. It is represented as t1/2.
Nt = No e^-yt
Nt = 27.7 %
No = 100%
t = 26.5 days
y = decay constant
t1/2 = half life = unknown
So therefore,we solve for the decay constant and then using the formula Half life = Ln 2/ decay constant, we solve for the half life.
Nt = No e^-yt
27.7 = 100 e ^-26.5 y
0.277 = e^-26.5 y
Take the natural log of both sides
Ln 0.277 = -26.5 y
y = Ln 0.277/ -26.5
y =-1.2837/ -26.5
y =4.84 *10 ^-2
Since half life = Ln 2 / y
Half life = ln 2 / 4.84*10-2
Half life = 1.1456 days.
Hence, the half life for the radioactive phosphorus -32 is 1.15 days.
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Answer: 17.34 grams of alum will be produced if 0.9875 g of Aluminium foil was used.
Explanation: Reaction to form alum from Aluminium is given as:
We are given Aluminium to be the limiting reactant, so the formation of alum will be dependent on Aluminium because it limits the formation of product.
By stoichiometry,
2 moles of Al is producing 2 moles of Alum
Mass of 2 moles of Aluminium = (2 × 27)g/mol = 54 g/mol
Mass of 2 moles of alum = (2 × 474)g/mol = 948 g/mol
54 g/mol of aluminium will produce 948 g/mol of alum, so
Amount of Alum produced = 17.34 grams
Theoretical yield of alum = 17.34 grams.