The correct answer is b. an element
The explanation:
when the ELEMENT is define as substance that cannot be decomposed (broken down) into simpler substances by ordinary chemical means. Examples: gold, iron, carbon, hydrogen, oxygen, nitrogen
Ex: diamond will be broken into carbon as well.
and SUBSTANCE: Material composed of only one kind of matter throughout (same atoms or same molecules).
The theoretical yield of Ca(OH)₂ : 42.032 g
<h3>Further explanation</h3>
Given
31.8 g of CaO
Required
The theoretical yield of Ca(OH)₂
Solution
Reaction
CaO + H₂O⇒Ca(OH)₂
mol CaO (MW=56 g/mol) :
= mass : MW
= 31.8 g : 56 g/mol
= 0.568
From equation, mol Ca(OH)₂ = mol CaO = 0.568
Mass Ca(OH)₂ (MW=74 g/mol) :
= 0.568 x 74
= 42.032 g
We need to dilute 0.400 mol of copper (II) sulfate, how do we know, how many weigh of
we have to dilute??
It's simple.
Using a periodic table we can find the molar mass of
Then
now we can replace it
Then we have to dilute 63.84 grams of copper (II) sulfate in 1 L of water to obtain a solution with 0.400M
<h3>Answer:</h3>
Br (Bromine)
<h3>Explanation:</h3>
Li and K,
As the electronegativity difference between Li and K is less than 1.7 therefore, ionic bond cannot form between these two metals.
Li and Fe,
The electronegativity difference is less than 1.7 so neither electron loss nor electron gaining will take place between these two metals. Therefore, there will be no ionic bond between them.
Li and Kr,
As Krypton is a noble gas and does not react due to complete octet hence the formation of KrLi is difficult. However, Krypton can make compounds like KrF₂ e.t.c. Therefore we can skip this option.
For Li and K,
E.N of Bromine = 2.96
E.N of Lithium = 0.98
________
E.N Difference 1.98 (Ionic)
This ionic compound is possible and is the correct option because ionic compounds are always made by metals and non metals and here the combination is perfect.
<h3>Conclusion:</h3>
Lithium (a metal) and form Ionic bond with Bromine (a non metal)
