<span>Well it depends on percentage by what, but I'll just assume that it's percentage by mass.
For this, we look at the atomic masses of the elements present in the compound.
Cu has an atomic mass of 63.546 amu
Fe has 55.845 amu
and S has 36.065 amu
Since there are 2 molecules of Sulfur for each one of Cu and Fe, we'll multiply the Sulfur atomic weight by 2 to obtain 72.13 amu
So we have not established the mass of the compound in amus
63.546 + 55.845 + 72.13 = 191.521
That is the atomic mass of Chalcopyrite. and Iron's atomic mass is 55.845
So to get the percentage, or fraction of iron, we take 55.845 / 191.521
Which comes out to 29.15% by mass
Mass of the sample is not needed for this calculation, but since the question mentions it I would go ahead and check if the question isn't also asking for the mass of Iron in the sample as well, in which case you just find the 29.15% of 67.7g</span>
<span>Much like tornado watchers look to the skies for clues that a twister is forming, NASA and university scientists are watching the Sun in an effort to better predict space weather – blasts of particles from the Sun that impact the magnetosphere, the magnetic bubble around the Earth.</span>
Answer:
Using solar energy, hydroelectric energy and wind are major ways of conserving natural resources. Trees and other organic energy sources are traditional sources of renewable energy. Forests can be replanted and hemp and other organic materials such as ethanol can be used to preserve natural resources.
