Answer: Option B) Atom
Explanation:
An atom is the simplest particle of an element that can retain all the chemical properties of the element, and therefore take part in a chemical reaction.
Thus, an atom of zinc (Zn) represent fully the entire properties of elemental Zinc. For instance: an atom of zinc has a mass of 65.38g.
<span>Ionization energy is the energy needed to remove an electron from an atom or ion in a gas phase. The atom will become a cation and has an excess of proton, thus it will be positively charged. Ionization energy usually removes the most loosely bound valence electron.</span><span />
<u>Given:</u>
Charge on potassium (K) = +1
Charge on selenium (Se) = -2
<u>To determine:</u>
The values of X and Y in K(X)Se(Y)
<u>Explanation:</u>
The molecule which is formed between K and Se is neutral.
The K+ and Se2- ions should combine such that the net charge on the molecule is zero.
X(K+) + Y(Se2-) = 0
X(+1) + Y(-2) = 0
The simplest solution to the above equation is obtained when X = 2 and Y = 1
Thus, the molecule would be: K₂Se₁
Ans: X = 2 and Y = 1; K₂Se₁
a. AlCl₃ ⇒ limiting reactant(smaller ratio)
Cu ⇒ excess reactant
b. the mass of leftover reactant : 7.207 g
<h3>Further explanation</h3>
Given
25 g Cu
25 g AlCl3
Required
a. the excess and limiting reactants
b. the mass of leftover reactant
Solution
Reaction
3Cu + 2AlCl₃ ⇒ 3CuCl₂ + 2Al
mol Cu(Ar = 63.5 g/mol) :
mol = mass : Mw
mol = 25 : 63.5
mol = 0.394
mol AlCl3(MW=133,34 g/mol) :
mol = 25 : 133,34 g/mol
mol = 0.187
mol ratio to reaction coefficient Cu : AlCl₃ =
AlCl₃ ⇒ limiting reactant(smaller ratio)
Cu ⇒ excess reactant
b. the mass of leftover reactant :
mol Cu = 3/2 x 0.187 = 0.2805
mol left = 0.394 - 0.2805 = 0.1135
mass = 0.1135 x 63.5 = 7.207 g