Sorry, Cant really tell how to differentiate the students and trial times
Answer:
in a body of 165 pounds, the iron content is 2993.707 mg
Explanation:
- % iron = 0.0040% = (mass iron / mass human) * 100
⇒ mass iron / mass human = 4 E-5
∴ mass human = 165 pounds
⇒ mass iron = 165 pounds * 4 E-5
⇒ mass iron = 6.6 E-3 pounds * ( 453.592 g/pound ) * ( 1000 mg/g )
⇒ mass iron = 2993.707 mg iron
Answer:
0.125 mole
Explanation:
From Avogadro's hypothesis, we discovered that 1 mole of any substance contains 6.02x10^23 atoms.
The statement above suggests that 1 mole of chromium contains 6.02x10^23 atoms.
Now, if 1mole of of chromium contains 6.02x10^23 atoms,
Then Xmol of chromium contains 7.52x10^22 atoms i.e
Xmol of chromium = 7.52x10^22/6.02x10^23
Xmol of chromium = 0.125 mole
Therefore, 0.125 mole of chromium contains 7.52x10^22 atoms
Q1)
the number of moles can be calculated as follows
number of moles = mass present / molar mass
number of moles is the amount of substance.
4.8 g of Ca was added therefore mass present of Ca is 4.8 g
molar mass of Ca is 40 g/mol
molar mass is the mass of 1 mol of Ca
therefore if we substitute these values in the equation
number of moles of Ca = 4.8 g / 40 g/mol = 0.12 mol
0.12 mol of Ca is present
q2)
next we are asked to calculate the number of moles of water present
again we can use the same equation to find the number of moles of water
number of moles = mass present / molar mass
3.6 g of water is present
sum of the products of the molar masses of the individual elements by the number of atoms
H - 1 g/mol and O - 16 g/mol
molar mass of water = (1 g/mol x 2 ) + 16 g/mol = 18 g/mol
molar mass of H₂O is 18 g/mol
therefore number of moles of water = 3.6 g / 18 g/mol = 0.2 mol
0.2 mol of water is present
1 pm = 10∧-10 cm
Therefore, 230 pm is equivalent to 2.3 ×10∧-8 cm.
Atom is in the shape of a sphere,
The volume of a sphere is given by 4/3πr³
Thus, volume of the atom = 4/3π( 2.3 ×10∧-8)³
= 4/3 (3.142 ×12.167×10∧-24
= 5.096 ×10∧-23 cm³
but 1m³= 1000000cm³
Therefore, the volume of the atom = 5.096 ×10∧-29 m³
