Question

Question #e71b7

Answer 1

You need to supply 23 kJ of heat.

Explanation:

The formula for the quantity of heat `"q"` is

`color(blue)(bar(ul(|color(white)(a/a)q = mcΔTcolor(white)(a/a)|)))" "`

where

`m color(white)(ll)=` the mass of the object
`C color(white)(ll)=` its specific heat capacity
`ΔT =` its change in temperature

In this problem,

`m color(white)(ll)= "72 g"`
`C color(white)(ll)= "4.184 J·°C"^"-1""g"^"-1"`
`ΔT = "75 °C"`

∴ `q = 72 color(red)(cancel(color(black)("g"))) × "4.184 J"·color(red)(cancel(color(black)("°C"^"-1""g"^"-1"))) × 75 color(red)(cancel(color(black)("°C"))) = "23 000 J" = "23 kJ"`