You weigh an empty dish and find its mass to be 48.0 grams. After you add a volume of salt water to the dish the mass of the dish and salt water is now 74.0 grams. After 100% of the water has been evaporated, the mass of the dish and the remaining salt is 52.5 grams. What is the mass of just the water in the salt water you added to the dish?

Question

You weigh an empty dish and find its mass to be 48.0 grams.  After you add a volume of salt water to the dish the mass of the dish and salt water is now 74.0 grams.  After 100% of the water has been evaporated, the mass of the dish and the remaining salt is 52.5 grams.  What is the mass of just the water in the salt water you added to the dish?

DrBob222 · Answer

74.0 g = mass dish+mass salt+mass water
-52.5 g = mass dish + mass salt
-----------------==========
21.5 g = mass water
Note that if you subtract equation 2 from equation 1 the number is 21.5 g and the mass dish + mass salt cancel leaving mass water.