4- The reaction

NO(g)+(1)/(2)Br_(2)(g)->NOBr(g)

order in

Br_(2)(g)

and first-order in

NO(g)

.\ a) Write the rate law\ b) How does the reaction rate change if the

Br_(2)(g)

concentration doubles?\ c) What is the change in rate if the concentrations of both reactants are tripled?\ a) Rate

=k[NO]*[Br_(2)]^(2)

\ b) Rate

=k[NO]*[2xBr_(2)]^(2),

Rate

=k[NO]*4[Br_(2)]^(2)

\ Rate

=4\\\\times {k[NO]*[Br_(2)]^(2)}

The rate will quadruple\ c) Rate

=k3[NO]*[3xBr_(2)]^(2)

Rate

=k3[NO]*9[Br_(2)]^(2)

\ Rate

=27{k[NO]*[Br_(2)]^(2)}*

Rate

\\\\times 27

\ 5- The reaction

C_(2)H_(6)(g)->C_(2)H_(4)(g)+H_(2)(g),

is a first order reaction with a half-life

t_((1)/(2))=1.283sec

How long would it take for the concentration of

C_(2)H_(6)

to drop to

66%

of its initial amount?\

In {([C_(2)H_(6)]_(c))/([C_(2)H_(6)]_(0))}=-kt.,k=(0.693)/(t_((1)/(2)))=(0.693)/(1.283)k=0.54s^(-1)\ ln{(0.66*[C_(2)H_(6)]_(0))/([C_(2)H_(6)]_(0))}=-0.54\\\\times t\ -0.4155=-0.54\\\\times t\ t=0.77sec

\

t=0.77sec

4- The reaction NO(g)+1/2Br2(g) order in Br2(g) and first-order in NO(g). a) Write the rate law b) How does the reaction rate change if the Br2(g) concentration doubles? c) What is the change in rate if the concentrations of both reactants are tripled? a) Rate =k[NO][Br2]2 b) Rate =k[NO][2xBr2]2 Rate =k[NO]4[Br2]2 Rate =4{k[NO][Br2]2} The rate will quadruple c) Rate=k3[NO][3Br2]2Rate=27{k[NO][Br2]2}Rate=k3[NO]9[Br2]2Ratex27 5- The reaction C2H6(g)C2H4(g)+H2(g) is a first order reaction with a half-life t1/2=1.283sec How long would it take for the concentration of C2H6 to drop to 66% of its initial amount? ln{[C2H6]t/[C2H6]0}=kt.k=0.693/t1/2=0.693/1.283k=0.54s1ln{(0.66[C2H6]0)/[C2H6]0}=0.54t0.4155=0.54tt=0.77sec