Since you provide no options, Henry Moseley measured a property linked to Periodic Table position. After his revisions to the periodic table, Atomic number became more meaningful and the three pair of elements that seemed to be in the wrong order could be explained
First let us determine the electronic configuration of
Bromine (Br). This is written as:
Br = [Ar] 3d10 4s2 4p5
Then we must recall that the greatest effective nuclear
charge (also referred to as shielding) greatly increases as distance of the
orbital to the nucleus also increases. So therefore the electron in the
farthest shell will experience the greatest nuclear charge hence the answer is:
<span>4p orbital</span>
Answer:
of acetic anhydride is needed
Explanation:
According to balanced equation, 1 mol of salicylic acid completely reacts with 1 mol of acetic anhydride
Number of moles = (mass)/(molar mass)
Molar mass of acetic anhydride = 102.09 g/mol
Molar mass of salicylic acid = 138.121 g/mol
So, 
of salicylic acid = 
of salicylic acid
Hence, of salicylic acid reacts completely with of acetic anhydride.
So, mass of acetic anhydride needed = 
=
The mass percent of potassium chloride is 1.386%
<u><em>calculation</em></u>
mass percent = actual mass/ Theoretical mass x 100
Actual mass = 9.35 g
Theoretical mass is calculated as below
Step 1 : write the equation for reaction
KCl + H₂O → KOH + HCl
Step 2: find the moles of H₂O
moles = mass÷ molar mass
The molar mass of H₂O = (2 x1 ) +(16) = 18 g/mol
moles is therefore = 162.98 g÷ 18 g/mol =9.054 moles
Step 3: use the mole ratio to determine the moles of KCl
KCl: H₂O is 1:1 therefore the moles of KCl is also = 9.054 moles
Step 4: find the theoretical mass of KCl
mass = moles x molar mass
from periodic table the molar mass of KCl = 39 +35.5 =74.5 g/mol
mass = 9.054 moles x 74.5 g/mol =674.5 g
Theoretical mass is therefore = 9.35 g/ 674.5 g x 100 = 1.386%
