Ta có PT cân bằng nhiệt:

Q_thu=Q_tỏa

=> m₁c₁(t₁ - t) = m₁c₁(t - t₂)

=> m₂=\(\dfrac{m_1c_1\left(t_1-t\right)}{c_2\left(t-t_2\right)}\)

=>m₂=\(\dfrac{0,1.130\left(110-70\right)}{4200\left(70-50\right)}\)

=>m₂\(\approx0,006kg\)

KL:..