Answer:
B. Poor conductor.
Explanation:
It cannot be A, as only 1 metal is not solid at room temp.
It cannot be C, as most metals are ductile.
It cannot be D, as most metals are malleable.
This leaves B, which is not true about metals, as a lot are very good conductors.
Answer:
230.3 kJ
Some chemical reactions show release of heat while some show absorption of heat. On these bases, the reaction is classified as either endothermic or exothermic. Negative sign of ΔH means exothermic reaction.
The four ionic species initially in solution are Na⁺, PO₄³⁻, Cr³⁺, and Cl⁻. Since the precipitate is composed of Cr³⁺ and PO₄³⁻ ions, the spectator ions must be Na⁺ and Cl⁻.
The complete ionic equation is 3Na⁺(aq) + PO₄³⁻(aq) + Cr₃⁺(aq) + 3Cl⁻(aq) → 3Na⁺(aq) + 3Cl⁻(aq) + CrPO₄(s).
So the balanced <u>net ionic equation</u> for this reaction would be Cr³⁺(aq) + PO₄³⁻(aq) → CrPO₄(s).
Answer:
Rate constant = 0.0237 M-1 s-1, Order = Second order
Explanation:
In this problem, it can be observed that as the concentration decreases, the half life increases. This means the concentration of the reactant is inversely proportional to the half life.
The order of reaction that exhibit this relationship is the second order of reaction.
In the second order of reaction, the relationship between rate constant and half life is given as;
t1/2 = 1 / k[A]o
Where;
k = rate constant
[A]o = Initial concentration
k = 1 / t1/2 [A]
Uisng the following values;
k = ?
t1/2 = 113
[A]o = 0.372M
k = 1 / (113)(0.372)
k = 1 / 42.036 = 0.0237 M-1 s-1
The first step to solve this problem is to multiply the volume of solution times its concentration to find the number of moles needed, remember that M=mol/L:
Now, use the molar mass of sucrose to find the number of grams needed to make the solution. This is, multiply the number of moles needed times the molar mass:
It means that to make 0.500L of a 0.475M you will have to weigh 81.225g of sucrose.
