The mass of piece of sterling silver jewelry is 33.24 g. It contains 92.5% silver Ag by mass. Since, sterling silver is an alloy of Ag-Cu thus, percentage of Cu will be:
% Cu=100-92.5=7.5%
Thus, mass of copper will be:
Molar mass of Cu is 63.546 g/mol, thus, number of moles of Cu can be calculated as follows:
Here, m is mass and M is molar mass.
Putting the values,
Now, in 1 mole of Cu there are 
thus, in 0.03923 mol, number of Cu atoms will be:
Thus, number of atoms of Cu will be
.
First option.
The male tails are more attractive because of their long feathers , meanwhile the female tails are shorter than expected!
150/30 = 5
HF1 20/2 = 10
HF2 10/2 = 5
HF3 5/2 = 2.5
HF4 2.5/2 = 1.25
HF5 1.25/2 = 0.625
Answer: 0.63g
In a high-mass star, hydrogen fusion occurs via the CNO (Carbon-Nitrogen-Oxygen) cycle.
According to the life cycle of a star, there are three main phases in the life of a star: The initial phase (a quick phase), short phase or supergiant phase and death phase or supernova explosion.
the CNO cycle means Carbon-Nitrogen-Oxygen cycle and this process tale place during main sequence phase.
In this phase, hydrogen fuses into helium as a result of six different reaction taking place inside a star.
The first step of the sequence begins when the nucleus of carbon 12 isotope emits gamma rays after capturing a proton and produces nitrogen-13.
This whole cycle is known as stellar nucleosynthesis.
If you need to learn more about Carbon-Nitrogen Cycle click here:
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