Consider the reaction 2 hbr (g) à h2 (g) + br2 (g) a. express the rate of the reaction in terms of the change in concentration of each of the reactants and products. b. in the first 25.0 s of this reaction, the concentration of hbr drops from 0.600 m to 0.512 m. calculate the average rate of the reaction during this time interval.

The decomposition of HBr takes place according to the reaction below,
 2HBr(g) = H2(g)+ Br2(g)
a) Rate of reaction is the measure of the change in concentration of the reactants or the change in concentration of the product per unit time(seconds).
Therefore;
 Rate = -1/2(Δ(HBr)/Δt = Δ(H₂)/Δt =Δ(Br₂)/Δt,

where ΔHBr is the change in concentration of HBr (reactant), ΔH₂ is the change in hydrogen concentration , ΔBr₂ is the change in bromine concentration and Δt is the change in time.

b) Average rate of reaction after 25 sec will be,
 
 rate = -1/2Δ(HBr)/Δt
        = -1/2 (0.512 M - 0.6 M)/(25 s-0 s)

        = -1/2 (-0.088)/25
        = 0.00176 M/s

The rate of reaction in terms of concentration change has been given by

   =    =  .

The rate of reaction when the concentration of HBr has been dropped to 0.512 M has been 1.76 M/s.

(a) The rate of reaction can be defined as the change in concentration of the reactant and product per unit time.

The rate of reaction in terms of reactant change can be given by:

Rate = n

where, n is the coefficient, has been the change in reactants concentration, and has been the change in the time.

For the given reaction, the rate for change in each reactant and product has been:

Rate =  =    =  

(b) The change in the concentration of HBr has been:

= 0.60 M - 0.512 M

= 0.088 M

= 25 sec.

The rate of reaction in terms of HBr concentration has been:

Rate =  

Rate =

Rate = 0.00176 M/s

Rate = 1.76 M/s.

The rate of reaction when the concentration of HBr has been dropped to 0.512 M has been 1.76 M/s.

For more information about the rate of reaction, refer to the link:

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33 grams

Explanation:

CO2 is the chemical formula of carbon dioxide.

Given that:

Amount of moles of CO2 (n) = 0.75

Mass of CO2 in grams = ?

Obtain molar mass of CO2 using the atomic masses of the individual elements

Carbon = 12g; O = 16g

CO2 = [12g + (16g x 2)

= 12g + 32g

= 44 g/mol

Since, n = mass in grams / molar mass

0.75 moles = mass in grams / 44g/mol

mass in grams = 0.75 moles x 44g/mol

mass in grams = 33

Thus, the mass of 0.75 moles of CO2 is 33 grams