One of your chores is to mow the lawn. The lawnmower runs on gasoline. The gasoline burning is a
and the grass being cut is a
A. physical change, chemical change
OB. chemical change, physical change
C. physical change, physical property
OD chemical property, physical change

At a certain temperature the rate of this reaction is first order in hi with a rate constant of : 0.0632s2hig=h2g+i2g suppose a vessel contains hi at a concentration of 1.28m . calculate how long it takes for the concentration of hi to decrease to 17.0% of its initial value. you may assume no other reaction is important. round your answer to 2 significant digits.