Question

A container has `12 L` of water in it at `90 ^o C`. An object with a specific heat of `750 (KJ)/(Kg*K)` and a temperature of `250 ^oC` is placed into the container. If the water is completely vaporized, what is the object's mass?

Answer 1

The mass is `0.245" kg"`.

Explanation:

The heat is transferred from the hot object to the cold water.

The temperature of the water is `T_w=90^@"C"`

The temperature of the object is `T_o=250^@"C"`

`m_o C_o (DeltaT_o-100) = m_w C_w (100-90)+m_wH_w`

The specific heat of water is `C_w=4.186kJkg^-1K^-1`

The specific heat of the object is `C_o=750"kJ""kg"^-1K^-1`

The heat of vaporisation of water is `H_w=2257"kJ""kg"^-1`

The mass of the object is `m_0=?kg`

The mass of the water is `m_w=12kg`

`m_o 750 (250-100) = 12 *4.186 (100-90)+12*2257`

`112500m_o=27586`

`m_o=27586/1112500=0.245" kg"`

I hope that helps!