Answer : The number of iron atoms present in each red blood cell are, 
Explanation :
First we have to calculate the moles of iron.
Now we have to calculate the number of iron atoms.
As, 1 mole of iron contains 
number of iron atoms
So, 0.0519 mole of iron contains 
number of iron atoms
Now we have to calculate the number of iron atoms are present in each red blood cell.
Number of iron atoms are present in each red blood cell = 
Number of iron atoms are present in each red blood cell = 
Number of iron atoms are present in each red blood cell =
Therefore, the number of iron atoms present in each red blood cell are,
Answer:
0.17 moles
Explanation:
In the elements of the periodic table, the atomic mass = molar mass. <u>Ex:</u> Atomic mass of Carbon is 12.01 amu which means molar mass of Carbon is also 12.01g/mol.
In order to find the # of moles in a 12 g sample of NiC-12, we will need to multiply the number of each atom by its molar mass and then add the masses of both Nickel and C-12 found in the periodic table:
- Molar Mass of Ni (Nickel): 58.69 g/mol
- Molar Mass of C (Carbon): 12.01 g/mol
Since there's just one atom of both Carbon and Nickel, we just add up the masses to find the molar mass of the whole compound of NiC-12.
- 58.69 g/mol of Nickel + 12.01 g/mol of Carbon = 70.7 g/mol of NiC-12
There's 12g of NiC-12, which is less than the molar mass of NiC-12, so the number of moles should be less than 1. In order to find the # of moles in NiC-12, we need to do some dimensional analysis:
- 12g NiC-12 (1 mol of NiC-12/70.7g NiC-12) = 0.17 mol of NiC-12
- The grams cancel, leaving us with moles of NiC-12, so the answer is 0.17 moles of NiC-12 in a 12 g sample.
<em>P.S. C-12 or C12 just means that the Carbon atom has an atomic mass of 12amu and a molar mass of 12g/mol, or just regular carbon.</em>
Answer: C) Elements and pure compounds are homogeneous materials because they have a uniform composition throughout.
Explanation: Element is a pure substance which is composed of atoms of similar elements. Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.
Elements are compounds form homogeneous materials as they have uniform composition throughout and the components are evenly distributed throughout the material.
Mixtures are heterogeneous materials as they do not have uniform composition and the components are not evenly distributed throughout the material.
