Answer:
Explanation:
To solve this problem, we must understand the relationship between mass of a substance and the number of atoms.
Atoms are the smallest indivisible particles of any matter. A substance can be made up of several number of atoms in their space.
The mass of any substance is a function of the amount of atoms its contains.
The mass of a substance is related in chemistry to the amount of atoms its contains using the parameter called the number of moles.
A mole is the amount of substance that contains the Avogadro's number of particles. This number is 6.02 x 10²³ particles. The particles here can be protons, neutrons, electrons, atoms e.t.c.
Now,
Number of moles = 
Molar mass of copper = 63.6g/mole
Number of moles = 
= 0.03mole
Since 1 mole of a substance contains 6.02 x 10²³atoms
0.03 mole of copper will contain 0.03 x 6.02 x 10²³atoms
= 1.89 x 10²² atoms
He needs to add 1.89 x 10²² atoms to make 2g of the sample.
If the absorbance of a solution of curcumin which is too concentrated is measured, the absorbance will be unusually high.
Spectrometry measures the interaction of light with molecules. The absorbance refers to how much light that interacts with molecules of the substance. The more the concentration of the substance the higher the absorbance of the solution.
Hence, if the absorbance of a solution of curcumin which is too concentrated is measured, the absorbance will be unusually high. An unusually high absorbance tells us that the solution is too concentrated.
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Answer:
12.9 m³ is the new volume
Explanation:
As the temperature keeps on constant, and the moles of the gas remains constant too, if we decrease the pressure, the volume will increase. If the volume is decreased, pressure will be higher.
The relation is this: P₁ . V₁ = P₂ . V₂
1 atm . 0.93m³ = 0.072 atm . V₂
0.93m³ .atm / 0.072 atm = V₂
V₂ = 12.9 m³
In conclusion and as we said, pressure has highly decreased so volume has highly increased.
Given data Atomic mass of Ra= 226g/mol
no. of moles =1.0/226g/mol =0.04424moles
no. of atoms in 0.044moles
no. of atoms =no. of moles x avogadro's number
= 0.044x 6.022 x10^23 = 0.264968 x 10^22
If 10^15 atoms of Ra produce 1,373*10^4 atoms of<u> Rn per second</u> then 2,66 *10^21 forms 3,658*10^10 atoms of Rn per second.
Day has 246060=86400 s
That means that 2,66x10^21 atoms of Ra produces 3,16 x10^15 atoms of Rn in a day.
N(Rn)=3.16* 10 ^15 n(Rn)=N/NA
n(Rn)=5,25*10−9 pV=nR*T
T=273.15K R=8,314
p=101325Pa V=n∗R∗T/p
V=5.25∗10^−9 ∗ 8.314 ∗ 273.15 / 101325
V=1.1810^−10 m^3 = 118 x10^-7 liters of Rn, measured at STP, are produced per day by 1.0 g of Ra
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