Question 1
Calculate the mass of NH
4ClO
4, molar mass = 117.49 g mol
-1, required to create a temperature change of -1.0 °C in a coffee cup calorimeter containing 115 mL of water. The enthalpy of solution for NH
4ClO
4 is 33.47 kJ mol
-1. The specific heat of water is 4.184 J g
-1 °C
-1, and assume the density of the solution is 1.00 g mL
-1.
◦ 4.0 g
◦ 0.83 g
◦ 2.8 g
◦ 1.7 g
◦ 3.2 g
Question 2
Calculate the mass of sodium cyanate (NaOCN, molar mass = 65.0066 g mol
-1) required to lower the temperature from 24.1 °C to 23.0 °C in a coffee cup calorimeter containing 98 mL of water. The enthalpy of solution for NaOCN is 19.20 kJ mol
-1. The specific heat of water is 4.184 J g
-1 °C
-1 and assume the density of the solution is 1.00 g mL
-1.
◦ 3.8 g
◦ 1.5 g
◦ 4.8 g
◦ 0.75 g
◦ 1.1 g