ِAnswer:
1- The molarity of HCOOH = 9.515 M.
2- The mole fraction of HCOOH = 0.18.
Explanation:
<em>1- The molarity of HCOOH:</em>
- We can calculate the molarity of HCOOH using the relation:
M = (10pd)/molar mass.
p is the percent by mass of HCOOH = 35.9 %.
d is the specific gravity of HCOOH = 1.22 g/cm³.
Molar mass of HCOOH = 46.03 g/mol.
∴ M = (10pd)/molar mass = (10)(35.9 %)(1.22 gcm³) / (46.03 g/mol) = 9.515 M.
<em>2- The mole fraction of HCOOH:</em>
- We can suppose that we have a 100 g solution, that contains 35.9 g of HCOOH and 64.1 g of water.
<em>The mole fraction of HCOOH = (no. of moles of HCOOH) / (no. of moles of HCOOH + no, of moles of water).</em>
no. of moles of HCOOH = mass / molar mass = (35.9 g)/(46.03 g/mol) = 0.78 mol.
no. of moles of water = mass / molar mass = (64.1 g)/(18.0 g/mol) = 3.56 mol.
- The mole fraction of HCOOH = (no. of moles of HCOOH) / (no. of moles of HCOOH + no, of moles of water) = (0.78 mol) / (0.78 mol + 3.56 mol) = 0.18.
An alpha helix which is 18 amino acids long will have 12 hydrogen bonds.
<h3>What is alpha helix (α-helix) ?</h3>
The alpha helix (α-helix) is a common in the secondary structure of proteins and is a right hand-helix conformation in which every backbone N−H group hydrogen bonds to the backbone C=O. group of the amino acid located four residues earlier along the protein sequence.
The alpha helix is stabilized by hydrogen bonds (shown as dashed lines) from the carbonyl oxygen of one amino acid to the amino group of a second amino acid.
Because the amino acids connected by each hydrogen bond are four apart in the primary sequence, these main chain hydrogen bonds are called "n to n+4.
Learn more about protein structure here ;
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False
The water is more buoyant which means the water has more of a tendency to float than the duck.
Answer:
Volume = (0.62 m)^3
Explanation:
If the density of silver is 10.5 g/cm, the volume of the silver is (0.62 m)^3.
