Question

any problem(s) between 13 and 17

LES 3.00 x 13. The reaction. A + B is a first order reaction. At 760 K, 85% of a sample of A changes to B in 79.0 min. Calculate the value of the rate constant. (A) 6.10 x 10* s (B) 1.73 x 10-51 (D) 3.43 x 10' 51 (E) 4.00 x 10-2 C) 4.03 x 10251 14. A first-order reaction has a rate constant of 3.0 x 10''. The time required for the reaction to be 75% complete is (A) 95.8 s (B) 2015 (C) 231 s (D) 462 s (E) 41.75 15. The reaction, A - B is a first order reaction. The reaction is 40% complete in 50 min at 760 K. Calculate the half-life of the reaction? (A) 1.0 x 102 min (B) 69 min (C) 39 min (D) 58 min (E) 87 min 16. The reaction, A - B is a first order reaction. The reaction is 15% complete in 6.8 min at 760 K. Calculate the half-life of the reaction? (B) 2.5 min (A) 3.4 x 10-2 min (C) 23 min (D) 29 min (E) 230 min 17. A certain first-order reaction A-B is 25% complete in 42 min at 25 °C. What is the half-life of the reaction?

Answer 1

First order rate ean - out raz initial conc. a on = reacted Lue rate const te time taben 13) ob sample A changes to B in 79.0 min. 857 en 50, 2 In 100 h x79x60 100-pr Kaben 100 / 20x60) st a 4.00 x 10 -4 st 6 14) K= 3.0710331 tx=75%. so, en 100 2 3x10-3x t. (100-75 u t en het 13x103) z 462 S D 15 40%. complete in 30 min. so, en 10 a K.50 2) ke In 100 /5o mint 20.0102 min for 1st order reaction. tra eu? - ent mine the k. 0.0102 2 67.9 min 69min B

16) Reaction is 157. complete in cismin. en 100 = kx6.8 & ke lu 100 16.8 mint 0.0239 min to a o bu 2 min 229 min ① 17) 2 25% complete in 42 min en 100 ak+42 2) Ka en 100 /42 100-25 100 75 77 2 6.849x10-3 til en 2 a uz 6.8498103 101.19 min a