Answer:
0.023
Explanation:
The Arrhenius' equation states that:
Where k is the velocity constant of the reaction, A is the constant of the collisions, Ea is the activation energy (the energy necessary to the molecules have so the reaction will happen), R is the gas constant (8.314 J/molK) and T is the temperature.
This equation is derivated of:
k = pZf
Where
p=fraction of collisions that occur with reactant molecules properly oriented
f=fraction of collisions having energy greater than the activation energy
Z=frequency of collisions
Thus, p*Z = A, and
f = 
So, if the energy of the molecules is 12.5 kJ/mol = 12500 J/mol, thus the fraction will be:
f = 
f = 0.023
Answer:
7,94 minutes
Explanation:
If the descomposition of HBr(gr) into elemental species have a rate constant, then this reaction belongs to a zero-order reaction kinetics, where the r<em>eaction rate does not depend on the concentration of the reactants. </em>
For the zero-order reactions, concentration-time equation can be written as follows:
[A] = - Kt + [Ao]
where:
- [A]: concentration of the reactant A at the <em>t </em>time,
- [A]o: initial concentration of the reactant A,
- K: rate constant,
- t: elapsed time of the reaction
<u>To solve the problem, we just replace our data in the concentration-time equation, and we clear the value of t.</u>
Data:
K = 4.2 ×10−3atm/s,
[A]o=[HBr]o= 2 atm,
[A]=[HBr]=0 atm (all HBr(g) is gone)
<em>We clear the incognita :</em>
[A] = - Kt + [Ao]............. Kt = [Ao] - [A]
t = ([Ao] - [A])/K
<em>We replace the numerical values:</em>
t = (2 atm - 0 atm)/4.2 ×10−3atm/s = 476,19 s = 7,94 minutes
So, we need 7,94 minutes to achieve complete conversion into elements ([HBr]=0).
Answer: orderly arrangement of particles
Explanation:
In a crystaline solid, the particles that compose the solid are arranged or packed in an orderly manner to form a three dimensional crystal lattice with a defined structure. Sodium chloride is a crystaline solid.
In an amorphous solid, the particles that compose the solid aren't arranged in an orderly manner hence the solid tends to be brittle, e.g glass
Answer:the initial composition of the reactants is
40cm^3 of CH4
40cm^3of H2
100cm^3 of H2O
Explanation:
Balanced reaction is
CH4 +H2+5/2O2______
CO2 +3H2O
Excess KOH at room temperature absorbs CO2 whose volume is given by 40cm^3 i.e the volume by which the solution decreases
So using Gay lussac combining ratio which states that gases combine in volumes that are in simple ratio to each other if gases.
Since CO2 in the equation is 1 mole
Means 1mole represent 40cm^3
So CH4:H2:O2 are in ratio of 1:1:5/2=(40:40:100)cm^3 respectively.
Answer:
The last choice.
Explanation:
It does not conduct electricity in any form.
They have no free electrons and do not ionise.
