<span>Water molecules form a complex with metal ions (usually a 6-coordinate complex). And the high charge density on a metal ion draws electrons away from the water molecules, making the O-H bonds more polar than normal. This allows the dissociation of the protons, making solutions of most metal ions acidic</span>
Answer:
4 g OF IODINE-131 WILL REMAIN AFTER 32 DAYS.
Explanation:
Half life (t1/2) = 8 days
Original mass (No) = 64 g
Elapsed time (t) = 32 days
Mass remaining (Nt) = ?
Using the half life equation we can obtain the mass remaining (Nt)
Nt = No (1/2) ^t/t1/2
Substituting the values, we have;
Nt = 64 * ( 1/2 ) ^32/8
Nt = 64 * (1/2) ^4
Nt = 64 * 0.0625
Nt = 4 g
So therefore, 4 g of the iodine-131 sample will remain after 32 days with its half life of 8 days.
Answer:
Metallic bonds
Explanation:
Metallic bonds joins atoms of metals and atoms of alloys together. The copper used in making pennies is a metallic substance so it contains metallic bonds.
- The formation of this bond type is predicated on the large atomic radius, low ionization energy and large number of electrons in the valence shell.
- The bond is an attraction between the positive nuclei of all closely packed atoms in the lattice and the electron cloud.
- The electron cloud is jointly formed by all the atoms by losing their outermost shell electrons.
This way the bond in pennies are metallic in nature.
These are two questions and two answers.
1) Question: Which of the following pairs of reactants will react together to produce water (H2O) as one of the products?
<span>Fe(OH)₃ and CuO
Cu(OH)₂ and H₂S
MgO and Ca(OH)₂
SO₃ and H₂O
</span>
<span>Answer:
</span>
<span>Cu(OH)₂ and H₂S
</span>
Justification:
1) Fe(OH)₃ and CuO: to form water Cu and Fe should react with each other. Being them two metals, they will not do that. So this reaction is not possible.
2) Cu(OH)₂ and H₂S: Being S a non metal and Cu a metal, they can react to form a the salt CuS, and water, as per this equation:
<span>Cu(OH)₂ + H₂S → CuS + 2H₂O
</span>
<span>
3) MgO and Ca(OH)₂: Being Mg and Ca two metals they will not react with each other, so this reaction is not feasible.
</span>
<span>4) SO₃ and H₂O: this is an acid oxide and water reaction which yields to an acid, as per this equation:
</span>
<span>SO₃ + H₂O → H₂SO₄
</span>
Which is not producing water
<span>2) Question: Based on reactivity, which of the following elements can replace
aluminum (Al) in a compound during a single replacement reaction?
B
Ca
Zn
Fe
</span>
Answer: Ca.
Justification:
Only an element more reactive than Al will replace it <span>in a compound during a single replacement reaction.</span>
You may predict that being Ca an alkalyne earth element it is more reactive than Al and so Ca will replace Al.
Else, you have to search a reactivity table, where you will find this order of reactivity among the metals:
Ca more reactive than Al
Al more reactive than Zn
Zn more reactive than Fe.
<span />
Being B a metalloid, its matallic character is low and it is less reactive than the other metals on the list.
Answer:
No effect will be observed since C is not included in the equilibrium expression.
Explanation:
Let's consider the following reaction.
CO₂(g) + C(graphite) ↔ 2 CO(g)
The equilibrium constant (Kc) is the product of the concentration of the products raised to their stoichiometric coefficients divided by the product of the concentration of the reactants raised to their stoichiometric coefficients.
Kc only includes gases and aqueous species (not liquids or solids).
As we can see, C is a solid and is not included in the equilibrium expression, so adding some C would have no effect on it.