Answer:
All of the given statements are true.
Explanation:
All the elements are heavier than Bismuth (Bi) are radioactive.
The time for half of the original sample to spontaneous decay is called half life (
)

All radioactive elements are spontaneously decaying towards formation of a stable element.
Radioactive elements undergo decay in order to attain stability.
Radioactivity is a natural part of our environment. The earth also contains several primordial long-lived radioisotopes that have survived to the present in significant amounts.
Hence, all the given statements are true.
Answer : The volume of gas occupy at
is, 1.25 L
Explanation :
Charles' Law : It states that volume of the gas is directly proportional to the temperature of the gas at constant pressure and number of moles.
Mathematically,

where,
are the initial volume and temperature of the gas.
are the final volume and temperature of the gas.
We are given:

Putting values in above equation, we get:

Therefore, the volume of gas occupy at
is, 1.25 L
C.Pennsylvania Titusville is in the state of Pennsylvania
Answer:
HCl + Ca(OH)2 = CaCl2 + H2O - Chemical Equation Balancer.