<h2>~<u>Solution</u> :-</h2>
Here, we have been given the the amount of helium to be 52 amu.
Thus,
- Atomic mass of Helium is 4u = 2 protons + 2
- Neutrons = 1 atom.
- No. of atoms in 52u = $ \sf{\frac{52}{4}}$ = 13 atoms.
$ \red{\leadsto}$ Hence, the number of atoms will be <u>13 atoms</u>.

Answer: An element is a pure substance. It can not easily be broken down into parts by physical means.
A)True
B)False
<u>The answer is true. </u>
Answer:
Option A= copper
Explanation:
According to specific heat capacity of substances, copper will reach to the our body temperature first.
Specific heat capacity:
It is the amount of heat required to raise the temperature of one gram of substance by one degree.
Formula:
Q = m × c × ΔT
specific heat capacity of copper = 0.385 J/g. °C
specific heat capacity of aluminium = 0.902 J/g. °C
so copper will absorb the heat very quickly and raise the temperature in very less time as compare to aluminium.
Answer:
The substance which responds to the change in the concentration of the hydronium ions in solution by changing its color is known as an indicator.