It will take 764 kJ of heat energy.
The energy qq required to heat an object is given by the formula
color(blue)(bar(ul(|color(white)(a/a)q = mcΔTcolor(white)(a/a)|)))" "
where
m is the mass
c is the specific heat capacity
ΔT is the change in temperature
In your problem,
m = "2.60 kg" = "2600 g"
c = "1.75 J·°C"^"-1""g"^"-1"
ΔT = T_"f" - T_"i" = "191 °C - 23 °C = 168 °C"
∴ q = 2600 color(red)(cancel(color(black)("g"))) × "1.75 J"·color(red)(cancel(color(black)("°C"^"-1"·"g"^"-1"))) × 168 color(red)(cancel(color(black)("°C"))) = "764 400 J" = "764 kJ"
