Answer:
Physical weathering is caused by the effects of changing temperature on rocks, causing the rock to break apart. The process is sometimes assisted by water. Freeze-thaw occurs when water continually seeps into cracks, freezes and expands, eventually breaking the rock apart
Explanation:
A chemical reaction is when you cant change something back to the way it was before
<u>Answer:</u> Electron has almost no mass.
<u>Explanation:</u>
Mass is defined as the actual matter that is contained in a substance. At an atomic level, it is expressed in atomic mass units.
The given options are the 3 subatomic particles.
Mass of the given subatomic particles are:
Proton = 1.007276u
Neutron = 1.008664u
Electron = 0.0005485u
Mass of neutron is slightly more than the mass of proton.
From the above information, it is visible that electron has a negligible mass.
Hence, the correct answer is electron.
Answer : The time taken for the concentration of the reactant in the reaction to fall to one-fourth of its initial value is, 12.4 seconds.
Explanation :
Half-life = 29.8 s
First we have to calculate the rate constant, we use the formula :



Now we have to calculate the time passed.
Expression for rate law for first order kinetics is given by:

where,
k = rate constant = 
t = time passed by the sample = ?
a = let initial amount of the reactant = x M
a - x = amount left after decay process = 
Now put all the given values in above equation, we get


Therefore, the time taken for the concentration of the reactant in the reaction to fall to one-fourth of its initial value is, 12.4 seconds.