What is the rate constant of a first-order reaction that takes 563 secondsseconds for the reactant concentration to drop to half of its initial value?

The rate constant of a first-order reaction that takes 563 secondsseconds for the reactant concentration to drop to half of its initial value is

Explanation:

Expression for rate law for first order kinetics is given by:

where,

k = rate constant

t = age of sample

a = let initial amount of the reactant

a - x = amount left after decay process  

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

Thus rate constant of a first-order reaction that takes 563 secondsseconds for the reactant concentration to drop to half of its initial value is

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.