<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>
There are 30 protons and 39 neutrons in the nucleus.
This must me the isotope of an element with an atomic mass close to 69 u.
The only candidates are Zn and Ga.
Zn has a zinc-69 isotope with mass 68.926 u.
Ga has a gallium -69 isotope with mass 68.925 u.
The isotope is probably
.
It has 30 protons and 39 neutrons.
Earth's shape & the tilt of its axis causes the Sun's rays to strike different parts of Earth's surface. I hope this helped :)
Answer:
1000 µL; 10 µL
Explanation:
A p1000 micropipet is set to dispense 1000 µL.
A p10 micropipet set to dispense 10 µL.
Answer:
The answer to your question is 58.7 g of Ca(OH)₂
Explanation:
Data
mass of Ca(OH)₂ = ?
mass of HNO₃ = 100 g
Process
1.- Write the balanced chemical reaction
Ca(OH)₂ + 2HNO₃ ⇒ Ca(NO₃)₂ + 2H₂O
2.- Calculate the molar mass of the reactants
Ca(OH)₂ = 40 + 32 + 2 = 74 g
HNO₃ = 1 + 14 + 48 = 63 g
3.- Use proportions to calculate the mass of Ca(OH)₂
74 g of Ca(OH)₂ ----------------- 2(63) g of HNO₃
x ----------------- 100 g of HNO₃
x = (100 x 74) / 2(63)
x = 7400 / 126
x = 58.7 g
