The enthalpy of solution of sodium hydroxide is -42.6 kJ.mol-1. What mass of sodium hydroxide would produce a temperature rise of 5.00 K when dissolved in 200.0 cm3 of water?
q = msΔt
mass of solution = mass of water + mass of sodium hydroxide
"m = m_w + m_{sh}"
M(NaOH) = 40 g/mol
n(NaOH) "= \\frac{m_{sh}}{40}"
1 mole of NaOH gives heat energy of 44.2 KJ
So, "q = 44200 \\times \\frac{m_{sh}}{40}"
The heat capacity is 4.184 J/C
"44200 \\times \\frac{m_{sh}}{40} = (200 + m_{sh}) \\times 4.184 \\times 5 \\\\\n\n1105 \\times m_{sh} = 4184 + 20.92 \\times m_{sh} \\\\\n\n1084.08 \\times m_{sh} = 4184 \\\\\n\nm_{sh} = 3.86 g"
Answer: 3.86 g
Comments
Leave a comment