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).
There are 1.48 × 10²⁵ molecules of zinc oxide in a 2 kg sample. Details about number of molecules can be found below.
<h3>How to calculate number of molecules?</h3>
The number of molecules of a substance can be calculated by multiplying the number of moles of the substance by Avogadro's number.
According to this question, there are 2000g of ZnO in a sample. Zinc oxide has a molar mass of 81.38 g/mol.
no of moles = 2000g ÷ 81.38g/mol
no of moles = 24.57mol
number of molecules = 24.57 × 6.02 × 10²³
number of molecules = 147.95 × 10²³
Therefore, there are 1.48 × 10²⁵ molecules of zinc oxide in a 2 kg sample.
Learn more about number of molecules at: brainly.com/question/11815186
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Explanation:
Given parameters:
Density of silver = 10.5g/cm³
Volume of silver given = 4mL
Unknown:
Mass of silver = ?
Solution:
Density of a substance can be expressed as its mass per unit volume
Density = 
we need to convert our volume to cm³ from mL;
1cm³ = 1mL
So 4mL = 4cm³
input the values in;
Mass = density x volume = 10.5 x 4 = 42g
learn more:
Density brainly.com/question/8441651
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Answer:
The statue of liberty was made of copper. Copper is extremely weather-resistant. It will gradually oxidize copper chloride, which is greenish in
Explanation:
Because it copper and it greenish
Answer:
The Moon weighs about 7.349*10^22 kg
How much does “an elephant” weigh? Grown-up elephants vary between 1.7 tons (small wood elephant cow) and 6 tons (big African elephant bull). Let us pick 2.720 tons or 2720 kg as an average weigh one, this is valid for Asian elephants.
A mole of elephants weighs 6.022 * 10^23 x 2720 kg = 1.638 * 10^27 kg.
That is 1,638 * 10^27 / 7,349*10^22 = 22289 times more.
