Heat is equal to product of mass, change in temperature and specific heat.
The formula is given by:
[tex]q=\Delta T\times C\times m[/tex]
where,
q = heat
[tex]\Delta T[/tex]= change in temperature that is [tex]45^{o}C-25^{o}C = 20 ^{o}C [/tex]
m = mass of substance
C= specific heat capacity
Put the values,
[tex]1.107\times 10^{2} J =20 ^{o}C \times C\times 12.3 g [/tex]
[tex]C= \frac{1.107\times 10^{2} J}{20^{o}C\times 12.3 g}[/tex]
[tex]C= \frac{1.107\times 10^{2} J}{246^{o}C g}[/tex]
= [tex]0.0045 \times 10^{2} J/^{o}C g[/tex]
= [tex]0.45 J/^{o}C g[/tex]
Specific heat capacity is equal to [tex]0.45 J/^{o}C g[/tex] and this value corresponds to element iron.
Thus, the unknown substance is iron.
