Answer:
Electron bonds break and reattach to other atoms
Explanation:
Most chemical reactions involve the breaking of bonds
It might be more suitable because some data cannot use a graph to show data because there is too much data.
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 ;
brainly.com/question/14652022
#SPJ1
Answer: pure substances.
Explanation:
The given substances are:
All what surrounds us, which has mass and occupies spaces, is matter. There are two kind of matter: pure substances and mixtures.
Pure substances have a uniform and constant composition. On the other hand, mixtures are combinations of two or more pure substances in any arbitratry ratio.
Pure substances may be elements or compounds. The elements are the substances conmposed by one only kind of atom. In the list of substances given, Li and O₂ are elements: all the atoms in Li are lithium, and all the atoms in O₂ are oxygen atoms.
Compounds are the chemical combination of two or more different kind of atoms. In the given list H₂O₂ and NaCl are compounds. As you see, H₂O₂ contains atoms of hydrogen and oxygen, chemically bonded, in a fixed ratio (2 atoms of hydrogen by 2 atoms of oxygen). And NaCl has atoms of Na (sodium) and Cl (chlorine), chemicaly bonded, in a fixed ratio (1:1).
There are only 118 known elements and you can find them in any modern periodic table. Therer are virtually infinitely many compounds since many different combinations of the elements can be attained.
Elements and compounds have in common that they are classified as pure substances.
69.9%
Explanation:
To find the mass percentage of iron in the compound in Fe₂O₃, we would go ahead to express the given molar mass of the iron to that of the compound.
Mass percentage = 
x 100
Molar mass of Fe = 55.85g/mol
Molar mass of O = 16g/mol
Molar mass of Fe₂O₃ = 2(55.85) + 3(16) = 159.7g/mol
Mass percentage = 
= 69.94% = 69.9%
learn more:
Mass percentage brainly.com/question/8170905
#learnwithBrainly
