Question #16cfd

1 Answer
Feb 2, 2018

#Q=ul?J#

Explanation:

  1. This can be solved using the standard formula shown below.

    #Q=mCpDeltaT#
    #where:#

    #Q="heat"=ul?#
    #m="mass"=3.3kg#
    #Cp="heat capacity"=(0.128J)/(g*^oC)#
    #DeltaT=T_f-T_i=67^oC-25^oC="change in temperature(final/initial)"#

  2. Check units for uniformity. This case, the mass of gold bar is expressed in #kg#; so that, this value must be converted to #g# to match the derived units of the #Cp# value of the material . Note that #1kg=1000g#; the equivalence statement, where a conversion factor is obtainable from; i.e.,

    #m=3.3cancel(kg)xx(1000g)/(1cancel(kg))#
    #m=3,300g#

  3. Now, plug in given values to the formula as shown in #"step " 1.# Cancel unwanted/cancellable units and make sure the desired unit is attained.

    #Q=mCpDeltaT#
    #Q=mCp(T_f-T_i)#
    #Q=(3,300cancel(g))((0.128J)/cancel((g*^oC)))(67-25)*cancel(^oC)#
    #Q=ul?J#