9:36 AM Personal Hotspot: 1 Connection ezto.mheducation.com ll GoSmart LTE @ * 6

Question

9:36 AM Personal Hotspot: 1 Connection ezto.mheducation.com ll GoSmart LTE @ * 61% ). + M 202-001 HW Chapter 13 nstruc Question 4 tot 15 10.00 points Check my Rep Be sure to answer all parts. The thermal decomposition of phosphine (PH3) into phosphorus and molecular hydrogen is a first-order reaction: 4PH3(g)-P(g) + 6H2(g) The half-life of the reaction is 35.0 s at 680 C. Calculate the first-order rate constant for the reaction: Guid Calculate the time required for 87.0 percent of the phosphine to decompose: es eBook & Resources Multipart Answer Dficuity 3

Explanation / Answer

we know,the rate constant (K) of a first order reaction is related to the half life of the reaction by the formula

K=0.693/t0.5 where t0.5 is the half life of the reaction.

Now in this case the t0.5=35.0 sec

so,the rate contant of the reaction(K)=(0.693/35) sec-1

=0.0198 sec-1

Now for the ans of second question,

the first order reaction kinetics gives the rate law as the following,

ln(A0/A)=Kt where A0=initial concentration of PH3

A=concentration remaining after time 't' i.e A=(100-87)%

=13%

so,

Kt=ln(100/13)

Kt=2.04

t=2.04/0.0198) sec

t=103 sec

Related Questions

Navigate

• Browse (All)
• Browse 9
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.