An object with a mass of 18 g18g is dropped into 400 mL400mL of water at 0^@C0C. If the object cools by 150 ^@C150C and the water warms by 12 ^@C12C, what is the specific heat of the material that the object is made of?

1 Answer
Dec 28, 2017

=(7.4311J)/(g*C)=7.4311JgC

Explanation:

  1. Given the volume of water used as medium to cool down the object, its mass can be derived through the density formula; that is,
    rho=m/Vρ=mV
    m=rhoxxVm=ρ×V
    m=(1g)/cancel((ml))xx400cancel(ml)
    m=400gH_2O
  2. Find the heat absorbed (gained) by the water that increases its temperature by 12^o. Knowing the Cp_w=(4.18J)/(g*C), heat gained can be calculated by:
    Q=mCpDeltaT
    Q=(400cancel(g))((4.18J)/cancel((g*C)))(12)cancel(^oC)
    Q=20,064J=20.064kJ
  3. Since heat lost=heat gained; therefore, the Cp of the material can be computed as;
    Q=mCpDeltaT
    Cp_(o)=(Q)/(mDeltaT)
    Cp_(o)=(20,064J)/((18g)(150^oC))
    Cp_(o)=(7.4311J)/(g*C)