A sample of aluminum, which has a specific heat capacity of 0.897·J·g−1°C^−1 , is put into a calorimeter (see sketch at right) that contains 300.0g of water. The aluminum sample starts off at 94.5°C and the temperature of the water starts off at 21.0°C .When the temperature of the water stops changing it's 23.8°C .The pressure remains constant at 1atm .Calculate the mass of the aluminum sample.

The mass of aluminium sample is 55.4 gram

Explanation:

As we know that,  

where,

= mass of aluminium = ?

= mass of water = 300.0 g

= final temperature =

= temperature of aluminium =

= temperature of water =

= specific heat of aluminium =

= specific heat of water =  

Now put all the given values in equation (1), we get

Therefore, the mass of aluminium sample is 55.4 gram

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.