A 52.9g sample of brass, which has a specific heat capacity of 0.375·J·g−1°C−1, is put into a calorimeter (see sketch at right) that contains 100.0g of water. The temperature of the water starts off at 15.0°C. When the temperature of the water stops changing it's 18.4°C. The pressure remains constant at 1 atm. Calculate the initial temperature of the brass sample. Be sure your answer is rounded to 2 significant digits.

T₁ = 90°C

Explanation:

Let system 1 => brass sample & system 2 => water

∑q = 0 = q₁ + q₂ =  (mcΔT)₁ + (mcΔT)₂

= [(52.9g)(0.375j/g°C)(18.4°C - T₁)]₁ + [(100.0g)(4.184j/g°C)(18.4°C - 15°C)]₂ = 0

=> 19.83(18.4°C - T₁) + 1423 = 0 => 365 - 19.83T₁ + 1423 = 0

=>19.83T₁ = 1788 => T₁ = (1788/19.83)°C = 90°C

it is to be noted that an alpha particle is an helium nucleus. so it contains 2 protons 2 neutrons and has a mass number of 4. when alpha decay particles are ejected from the nucleus it gets transformed into an atom which has atomic number less than 2 and a mass number less than 4.

an equation that could represent alpha decay is radium 226 decay of alpha particle forms radon 222.

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