Question #16cfd

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Answer 1 · 2018-02-02T20:41:46

$Q=ul?J$

This can be solved using the standard formula shown below.

$Q=mCpDeltaT$
$where:$

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

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

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