The mass number can vary without changing the identity of an atom whereas change in atomic number may not be possible.
Atomic number of an atom is the number of protons or electrons in an atom. So the atomic number is an essential criteria for the identification of an element. No two elements will have the same atomic number. Thus atomic number cannot be changed for a particular atom. This is because the number of protons cannot be changed.
Mass number is the sum of the number of protons and neutrons of an atom. This can be varied without changing the identity of atom. We call them isotopes. Some elements have more than one kind of atoms with different mass number but same atomic number. For example, Hydrogen has three isotopes. These are formed by the difference in the number of neutrons in an atom.
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Explanation:
The Chemical Equations are;
H2CO3 --> H2O + CO2
8Cu + S₈ --> 8 Cus
BaCO3 --> BaO + CO2
P₄ + 502 --> 2P205
KCIO3 --> KCI + O2
8Fe + S₈ --> 8Fes
The Reactions are;
Synthesis Reaction
Decomposition Reaction
A synthesis reaction occurs when two atoms or molecules react to form a different molecule or compound.
A decomposition reaction; a compound breaks into two or more products.
H2CO3 --> H2O + CO2 (Decomposition reaction)
8Cu + S₈ --> 8 CuS (Synthesis reaction)
BaCO3 --> BaO + CO2 (Decomposition reaction)
P₄ + 502 --> 2P205 (Synthesis reaction)
KCIO3 --> KCI + O2 (Decomposition reaction)
8Fe + S₈ --> 8Fes (Synthesis Reaction)
The chemical formula of hydrocortisone valerate is C26H38O6. First, we determine the molar mass of the substance by adding up all the products of the number of atoms and the molar mass of atoms as shown below.
molar mass = 26(12) + 38(1) + 6(16) = 446 g/mol
Since, there are 26 atoms of carbon in each molecule, the mass of carbon in each mole is
mass of carbon = (26)(12) = 312
Obtaining the percent by mass of carbon,
% by mass of carbon = (312/446) x 100 %
= 69.955%
Thus, the percent by mass of carbon in hydrocortisone valerate is approximately 69.96%.
The 2 L of sucrose stock solution would contain similar
concentration with the 100 mL aliquot. Therefore the concentration of aliquot
is still 2 M.
The molar mass of sucrose is 342.3 g / mol. Therefore the
mass in a 100 mL (0.1 L) aliquot is:
mass = (2 mol / L) * 0.1 L * (342.3 g / mol)
<span>mass = 68.46 g</span>