Answer:
show me a pic of the problem
Explanation:
show me a pic of the problem
An example of a physical change
is liquid water turning into vapor. Physical change is that it may involve a
change in phase but does not involve a change in molecular structure.
Answer: 243 hours
Explanation:
Expression for rate law for first order kinetics is given by:

where,
k = rate constant
t = age of sample
a = initial amount of the reactant = 
a - x = amount left after decay process = 
a) for completion of half life:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.


b) for reducing the mass to 10.00 % of its original mass



The time taken to reach 10.00 % of its original mass is 243 hours
Answer:
A. Gas atoms subjected to electricity emit bright lines of light
Explanation:
When subjected to electricity, the electrons of a gas atom are <em>excited</em>. From that excited energy level, the electrons eventually go back to their initial state; this <u>transition</u> is done by emitting photons at a specific wavelength (causing an emission of bright lines of light).
Such is the mechanism of gas-discharge lamps tipically found in households.
Biodiversity helps an economy grow and develop over time because such as the circle of life we need other things in order to evolve such as trees so we can be able to breathe and plants so the herbivores can eat so we can eat them because we are all part of a cycle and in order to keep the cycle going we need biodiversity to keep the food chain going and our economy well and lifted