Answer:
0.0141 kg/kg.
Explanation:
So, we are given the following parameters or information from the problem above:
The relative humidity = 10% was humidified to 40%, the temperature = 40°C.
From the chart, at temperature = 40°C and relative humidity = 10%, the weight of dry air = a1 = 0.0046 kg/kg, volume = 0.89 m³/kg.
Also, from the chart at temperature = 40°C and relative humidity = 40%, the weight of dry air = a2 = 0.00187 kg/kg, volume = 0.913 m³/kg.
Therefore, the amount of moisture added in the humidifier per kg of dry air = 0.0046 kg/kg - 0.00187 kg/kg = 0.0141 kg/kg.