The atomic number of sodium is 11. Sodium is a metal and it has the electronic configuration: 2, 8,1. This configuration implies that, the electrons in an atom of sodium are distributed into three different shells and the outermost shell has one electron in it. If sodium decide to give away the electron on its outermost shell, it will have 10 electrons left and those electrons will be distributed in only the first two shells and then it will be described as an ion. The third shell will not exist again because the electron there has been given away. Thus, the sodium ion is going to have a smaller atomic radius because its size has been reduced. This implies that the sodium ion will have a smaller radius than the sodium atom.
The required moles of CaO are needed to react with an excess of water to form 370 grams of calcium hydroxide is 280g.
Relation between the mass and moles of any substance will be represented as:
n = W/M, where
Given chemical reaction is:
CaO + H₂O → Ca(OH)₂
Moles of Ca(OH)₂ = 370g / 74g/mol = 5mol
From the stoichiometry of the reaction, 5 moles of CaO is required to produce 5 moles of Ca(OH)₂.
Mass of CaO = (5mol)(56g/mol) = 280g.
Hence required mass of CaO is 280g.
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Select one:
a. KF
b. MgF2
c. NO2
d. Na2S
B. 15 protons, 15 electrons
C. 60 protons, 30 electrons
D. 30 protons, 0 electrons
Answer:
Explanation:
The volume of KBr required can be found by using the formula;
c is the concentration in M , mol/dm³ or mol/L
v is the volume in L or dm³
m is the mass in grams
M is the molar mass in g/mol
From the question;
m = 25.5 g
c = 0.716
Molar mass (M) of KBr = 39 + 79.9 = 118.9 g/mol