They do not change the nature of the substance unless a chemical change occurs along with the physical change. These may be irreversible, but the result is still composed of the same molecules. When you cut your hair, that is a physical change, even though you can't put the hair back on your head again
Answer:
The correct answer is - 10400 years.
Explanation:
Half-life an element is the time required to decay the half amount of the initial amount of the element.
Here, the initial amount n(i) = 100 gm
remained amount n(r) = 25 gm
then n =?
The formula for the calculating initial amount
n(i)=n(r)⋅2^n
n(i)=n(r)⋅2^n
n(i)/n(r) =2^n
puting value,
100/25 = 2^n
2^n = 4
n = 2
so to decay this amount there is two half life cycles involved,
Thus, time = 2*5700
= 10400 years.
Answer:
A
Explanation:
When doing an experiment you want the most trials and most controls possible. It is impossible to get good data while testing multiple variables at once.
Answer:
A. Controlled variable
Explanation:
a controlled variable or a constant variable is a variable that doesnt change during an experiment
The molecular geometry is square planar.
According to the Valence Shell Electron Pair Repulsion theory (VSEPR), the shape of a molecule is determined by the number of valence electrons surrounding the outermost shell of the central atom in the molecule.
In this case, the expected geometry based on VSEPR theory is octahedral. However, the lone pairs on opposite sides of the four single bonds leads to a square planar molecular geometry.
Learn more; brainly.com/question/24396703