Question #37c52

1 Answer
Nov 5, 2016

Δ_"soln"H = "-1100 J/g"

Explanation:

There are two heat transfers involved.

"heat lost by dissolving NaOH + heat gained by water = 0"

q_1 + q_2 = 0

m_1Δ_"soln"H + m_2cΔT = 0

In this problem,

m_1 = "4.98 g"

m_2 = "49.72 g"
c = "4.184 J°C"^"-1""g"^"-1"
ΔT = T_f - T_i = "50.1 °C - 23.7 °C" = "26.4 °C"

q_1 = m_1Δ_text(soln)H= "4.98 g" × Δ_text(soln)H

q_2 = m_2cΔT = 49.72 color(red)(cancel(color(black)("g"))) × "4.184 J"·color(red)(cancel(color(black)("°C"^"-1""g"^"-1"))) × 26.4 color(red)(cancel(color(black)("°C"))) = "5492 J"

q_1 + q_2 = "4.98 g" × Δ_"soln"H+ "5492 J" = 0

Δ_"soln"H = "-5492 J"/"4.98 g" = "-1100 J/g"