Answer: At some point in your chemistry education, you may have been introduced to the song “The Elements in which Tom Lehrer does a rapid
fire musical rendition of all the elements' names. Like me, you may even have been offered the opportunity to memorize this song for extra credit. If so, it’s possible that you still remember the names of all the elements, which is an impressive feat—not to mention a fun trick to pull out at parties.
Explanation:
One mole of Na2SO4 is 6.022 * 10^(23) molecules. We can divide this into the quantity in the question to find a value of 1.5/6.022 = 0.2491 moles. Rounded to two significant figures and put in scientific notation, we can rewrite this quantity as 2.5 * 10^(-1) moles
Answer :
(a) The average rate will be:
![\frac{d[Br_2]}{dt}=9.36\times 10^{-5}M/s](https://tex.z-dn.net/?f=%5Cfrac%7Bd%5BBr_2%5D%7D%7Bdt%7D%3D9.36%5Ctimes%2010%5E%7B-5%7DM%2Fs)
(b) The average rate will be:
![\frac{d[H^+]}{dt}=1.87\times 10^{-4}M/s](https://tex.z-dn.net/?f=%5Cfrac%7Bd%5BH%5E%2B%5D%7D%7Bdt%7D%3D1.87%5Ctimes%2010%5E%7B-4%7DM%2Fs)
Explanation :
The general rate of reaction is,

Rate of reaction : It is defined as the change in the concentration of any one of the reactants or products per unit time.
The expression for rate of reaction will be :
![\text{Rate of disappearance of A}=-\frac{1}{a}\frac{d[A]}{dt}](https://tex.z-dn.net/?f=%5Ctext%7BRate%20of%20disappearance%20of%20A%7D%3D-%5Cfrac%7B1%7D%7Ba%7D%5Cfrac%7Bd%5BA%5D%7D%7Bdt%7D)
![\text{Rate of disappearance of B}=-\frac{1}{b}\frac{d[B]}{dt}](https://tex.z-dn.net/?f=%5Ctext%7BRate%20of%20disappearance%20of%20B%7D%3D-%5Cfrac%7B1%7D%7Bb%7D%5Cfrac%7Bd%5BB%5D%7D%7Bdt%7D)
![\text{Rate of formation of C}=+\frac{1}{c}\frac{d[C]}{dt}](https://tex.z-dn.net/?f=%5Ctext%7BRate%20of%20formation%20of%20C%7D%3D%2B%5Cfrac%7B1%7D%7Bc%7D%5Cfrac%7Bd%5BC%5D%7D%7Bdt%7D)
![\text{Rate of formation of D}=+\frac{1}{d}\frac{d[D]}{dt}](https://tex.z-dn.net/?f=%5Ctext%7BRate%20of%20formation%20of%20D%7D%3D%2B%5Cfrac%7B1%7D%7Bd%7D%5Cfrac%7Bd%5BD%5D%7D%7Bdt%7D)
![Rate=-\frac{1}{a}\frac{d[A]}{dt}=-\frac{1}{b}\frac{d[B]}{dt}=+\frac{1}{c}\frac{d[C]}{dt}=+\frac{1}{d}\frac{d[D]}{dt}](https://tex.z-dn.net/?f=Rate%3D-%5Cfrac%7B1%7D%7Ba%7D%5Cfrac%7Bd%5BA%5D%7D%7Bdt%7D%3D-%5Cfrac%7B1%7D%7Bb%7D%5Cfrac%7Bd%5BB%5D%7D%7Bdt%7D%3D%2B%5Cfrac%7B1%7D%7Bc%7D%5Cfrac%7Bd%5BC%5D%7D%7Bdt%7D%3D%2B%5Cfrac%7B1%7D%7Bd%7D%5Cfrac%7Bd%5BD%5D%7D%7Bdt%7D)
From this we conclude that,
In the rate of reaction, A and B are the reactants and C and D are the products.
a, b, c and d are the stoichiometric coefficient of A, B, C and D respectively.
The negative sign along with the reactant terms is used simply to show that the concentration of the reactant is decreasing and positive sign along with the product terms is used simply to show that the concentration of the product is increasing.
The given rate of reaction is,

The expression for rate of reaction :
![\text{Rate of disappearance of }Br^-=-\frac{1}{5}\frac{d[Br^-]}{dt}](https://tex.z-dn.net/?f=%5Ctext%7BRate%20of%20disappearance%20of%20%7DBr%5E-%3D-%5Cfrac%7B1%7D%7B5%7D%5Cfrac%7Bd%5BBr%5E-%5D%7D%7Bdt%7D)
![\text{Rate of disappearance of }BrO_3^-=-\frac{d[BrO_3^-]}{dt}](https://tex.z-dn.net/?f=%5Ctext%7BRate%20of%20disappearance%20of%20%7DBrO_3%5E-%3D-%5Cfrac%7Bd%5BBrO_3%5E-%5D%7D%7Bdt%7D)
![\text{Rate of disappearance of }H^+=-\frac{1}{6}\frac{d[H^+]}{dt}](https://tex.z-dn.net/?f=%5Ctext%7BRate%20of%20disappearance%20of%20%7DH%5E%2B%3D-%5Cfrac%7B1%7D%7B6%7D%5Cfrac%7Bd%5BH%5E%2B%5D%7D%7Bdt%7D)
![\text{Rate of formation of }Br_2=+\frac{1}{3}\frac{d[Br_2]}{dt}](https://tex.z-dn.net/?f=%5Ctext%7BRate%20of%20formation%20of%20%7DBr_2%3D%2B%5Cfrac%7B1%7D%7B3%7D%5Cfrac%7Bd%5BBr_2%5D%7D%7Bdt%7D)
![\text{Rate of formation of }H_2O=+\frac{1}{3}\frac{d[H_2O]}{dt}](https://tex.z-dn.net/?f=%5Ctext%7BRate%20of%20formation%20of%20%7DH_2O%3D%2B%5Cfrac%7B1%7D%7B3%7D%5Cfrac%7Bd%5BH_2O%5D%7D%7Bdt%7D)
Thus, the rate of reaction will be:
![\text{Rate of reaction}=-\frac{1}{5}\frac{d[Br^-]}{dt}=-\frac{d[BrO_3^-]}{dt}=-\frac{1}{6}\frac{d[H^+]}{dt}=+\frac{1}{3}\frac{d[Br_2]}{dt}=+\frac{1}{3}\frac{d[H_2O]}{dt}](https://tex.z-dn.net/?f=%5Ctext%7BRate%20of%20reaction%7D%3D-%5Cfrac%7B1%7D%7B5%7D%5Cfrac%7Bd%5BBr%5E-%5D%7D%7Bdt%7D%3D-%5Cfrac%7Bd%5BBrO_3%5E-%5D%7D%7Bdt%7D%3D-%5Cfrac%7B1%7D%7B6%7D%5Cfrac%7Bd%5BH%5E%2B%5D%7D%7Bdt%7D%3D%2B%5Cfrac%7B1%7D%7B3%7D%5Cfrac%7Bd%5BBr_2%5D%7D%7Bdt%7D%3D%2B%5Cfrac%7B1%7D%7B3%7D%5Cfrac%7Bd%5BH_2O%5D%7D%7Bdt%7D)
<u>Part (a) :</u>
<u>Given:</u>
![\frac{1}{5}\frac{d[Br^-]}{dt}=1.56\times 10^{-4}M/s](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B5%7D%5Cfrac%7Bd%5BBr%5E-%5D%7D%7Bdt%7D%3D1.56%5Ctimes%2010%5E%7B-4%7DM%2Fs)
As,
![-\frac{1}{5}\frac{d[Br^-]}{dt}=+\frac{1}{3}\frac{d[Br_2]}{dt}](https://tex.z-dn.net/?f=-%5Cfrac%7B1%7D%7B5%7D%5Cfrac%7Bd%5BBr%5E-%5D%7D%7Bdt%7D%3D%2B%5Cfrac%7B1%7D%7B3%7D%5Cfrac%7Bd%5BBr_2%5D%7D%7Bdt%7D)
and,
![\frac{d[Br_2]}{dt}=\frac{3}{5}\frac{d[Br^-]}{dt}](https://tex.z-dn.net/?f=%5Cfrac%7Bd%5BBr_2%5D%7D%7Bdt%7D%3D%5Cfrac%7B3%7D%7B5%7D%5Cfrac%7Bd%5BBr%5E-%5D%7D%7Bdt%7D)
![\frac{d[Br_2]}{dt}=\frac{3}{5}\times 1.56\times 10^{-4}M/s](https://tex.z-dn.net/?f=%5Cfrac%7Bd%5BBr_2%5D%7D%7Bdt%7D%3D%5Cfrac%7B3%7D%7B5%7D%5Ctimes%201.56%5Ctimes%2010%5E%7B-4%7DM%2Fs)
![\frac{d[Br_2]}{dt}=9.36\times 10^{-5}M/s](https://tex.z-dn.net/?f=%5Cfrac%7Bd%5BBr_2%5D%7D%7Bdt%7D%3D9.36%5Ctimes%2010%5E%7B-5%7DM%2Fs)
<u>Part (b) :</u>
<u>Given:</u>
![\frac{1}{5}\frac{d[Br^-]}{dt}=1.56\times 10^{-4}M/s](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B5%7D%5Cfrac%7Bd%5BBr%5E-%5D%7D%7Bdt%7D%3D1.56%5Ctimes%2010%5E%7B-4%7DM%2Fs)
As,
![-\frac{1}{5}\frac{d[Br^-]}{dt}=-\frac{1}{6}\frac{d[H^+]}{dt}](https://tex.z-dn.net/?f=-%5Cfrac%7B1%7D%7B5%7D%5Cfrac%7Bd%5BBr%5E-%5D%7D%7Bdt%7D%3D-%5Cfrac%7B1%7D%7B6%7D%5Cfrac%7Bd%5BH%5E%2B%5D%7D%7Bdt%7D)
and,
![-\frac{1}{6}\frac{d[H^+]}{dt}=\frac{3}{5}\frac{d[Br^-]}{dt}](https://tex.z-dn.net/?f=-%5Cfrac%7B1%7D%7B6%7D%5Cfrac%7Bd%5BH%5E%2B%5D%7D%7Bdt%7D%3D%5Cfrac%7B3%7D%7B5%7D%5Cfrac%7Bd%5BBr%5E-%5D%7D%7Bdt%7D)
![\frac{d[H^+]}{dt}=\frac{6}{5}\times 1.56\times 10^{-4}M/s](https://tex.z-dn.net/?f=%5Cfrac%7Bd%5BH%5E%2B%5D%7D%7Bdt%7D%3D%5Cfrac%7B6%7D%7B5%7D%5Ctimes%201.56%5Ctimes%2010%5E%7B-4%7DM%2Fs)
![\frac{d[H^+]}{dt}=1.87\times 10^{-4}M/s](https://tex.z-dn.net/?f=%5Cfrac%7Bd%5BH%5E%2B%5D%7D%7Bdt%7D%3D1.87%5Ctimes%2010%5E%7B-4%7DM%2Fs)
1. Pure substances cannot be separated into any other kinds of matter, while a mixture is a combination of two or more pure substances.
2. A pure substance has constant physical and chemical properties, while mixtures have varying physical and chemical properties (i.e., boiling point and melting point).
3. A pure substance is pure, while a mixture is impure.
Answer:
This is an example of a food chain
Explanation:
Think of it as a chain reaction. The grass feeds and nourishes the prairie dog. Upon eating the prairie dog, the coyote gets the nutrients from both the grass the prairie dog ate and from the prairie dog itself.