Answer:
The specific heat of water is Cp = 4.184 
Explanation:
1. The specific heat can be expressed as:

where Q is the energy, m is the mass of water, and T2-T1 express the change in the temperature.
2. Replace values for mass, energy and temperature:

3. Solve the equation to obtain the specific heat of water:
Cp=4.184
13.4 billion years is 3 times of the half-life, 4.47 billion years. So the Uranium-238 will go through three times of half decay. So the remain percentage will be 50%*50%*50%=12.5%.
Α.fℓσυя αи∂ ѕυgαя αяє ѕιfтє∂ тσgєтнєя ιитσ α мєαѕυяιиg ¢υρ
Answer: 5.14 moles
Explanation:
heat supplied: 8280 J
The formula used for heat absorbed by an ideal gas:

where,
q = heat absorbed = 8280 J
= for monoatomic gas = 
n = number of moles
R = gas constant = 8.314 J/Kmol
= initial temperature = 206 K
= final temperature = 335 K
Now put all the given values in the above formula,


Thus there are 5.14 moles of gas in the container.