Via the half-life equation we have:

Where A is the amount initially and final amount after some time has passed, t is the time elapsed, h is the half life time and so:

Therefore there will be 2.8125 grams left after 140 seconds.
Answer :
the amount of heat,in joules, required to increase the temperature of a 49.5-gram sample of wanted from 22°c to 66°c is 9.104 Joules.
Explanation:
The answer can be calculated using the formula
Q = mCрΔT
where
Q is the amount of heat required in joules to raise the temperature.
m is the mass of the sample in Kg.
Cp is the specific heat of the sample in J/Kg°C.
ΔT is the change in temperature required.
Here, m = 49.5-gram = 0.0495 kg
Cp = 4.18 J/Kg°C (for water)
T₁ = 22°C ; T₂ = 66°C
ΔT = 66 - 22 = 44
Substituting values in Q = mCрΔT
Q = (0.0495)(4.18)(44)
Q = 9.104 J
Nothing is less dense than gas. gas is the least dense form of matter.
The state of atoms in a neon light when light is emitted is loss of energy.