Asample ofpolystyrene, which has a specific heat capacity of 1.880 j/g k, is put into a calorimeter that contains 100.0 g of water. the polystyrene sample starts off at 89.8 c and the temperature of water starts off at 19.0°c. when the temperature of the water stops changing it is 33.5°c. the pressure remains constant at 1.0 atm. calculate the mass of the polystyrene sample. be sure your answer is rounded to significant digits.

Answer : The mass of the polystyrene sample is 57.3 grams.

Explanation :

In this problem we assumed that heat given by the hot body is equal to the heat taken by the cold body.

where,

= specific heat of polystyrene =

= specific heat of water =

= mass of polystyrene = ?

= mass of water = 100.0 g

= final temperature of system =

= initial temperature of polystyrene =

= initial temperature of water =

Now put all the given values in the above formula, we get

Therefore, the mass of the polystyrene sample is 57.3 grams.

answer; i believe that the correct answer is (a) potassium(k)

answer: the value of enthalpy change will be -152.80 kj.

solution:

pressure = 1atm , temperature = = 298 k

given that pressure and temperature are same in both gases , the number of moles of both gases can be determined by the ideal gas equation.

according to reaction 3 moles no are reacting with 1 mol of ,then 0.49 mol of no will react with moles of ozone that is 0.16 moles of ozone. since, no is limiting reagent and is an excessive reagent.

enthalpy change for the reaction between the given volumes of the gases is :