<u>Answer:</u> The density of the given element is 
<u>Explanation:</u>
To calculate the edge length, we use the relation between the radius and edge length for BCC lattice:
where,
R = radius of the lattice = 0.17 nm
a = edge length = ?
Putting values in above equation, we get:
To calculate the density of metal, we use the equation:
where,
= density
Z = number of atom in unit cell = 2 (BCC)
M = atomic mass of metal = 56.08 g/mol
= Avogadro's number = 
a = edge length of unit cell = 
(Conversion factor: 
)
Putting values in above equation, we get:
Hence, the density of the given element is
Answer:
after 45 days 9 g left
Explanation:
Given data:
Half life Na-24 = 15 days
Mass of sample = 72 g
Mass remain after 45 days = ?
Solution:
Number of half lives passed:
Number of half lives = time elapsed / half life
Number of half lives = 45 days / 15 days
Number of half lives = 3
At time zero total amount = 72 g
After first half life = 72 g/ 2= 36 g
At 2nd half life = 36 g/2 = 18 g
At 3rd half life = 18 g/2 = 9 g
Thus after 45 days 9 g left.
Answer:
CuO(s) + H₂(g) --> Cu(s) + H₂O(l)
Explanation:
It is already balanced. You can see that the values of the elements of the reactants are equal to the values of the elements of the products.
With various extractions the amount of material left in the trash will be lower, ergo the extraction will be more perfect. Various extractions with fewer amounts of solvent are more efficient than a single extraction with a huge amount of solvent.
<u>Explanation:</u>
Surely multiple extractions are better than the single large extraction. Because extraction is about maximizing outside field communication between the two solvents, and you easily get more surface area contact with fewer amounts.
You can merge two smaller portions quicker and more completely than with large portions.
<span>261 million kilometers</span>
