Question

Lisa has a glass that has a mass of exactly 100 grams. She puts exactly 45 grams of acid in the glass, and then she adds 15 grams of crushed limestone. When the limestone touches the acid, it makes bubbles. Lisa waits until the reaction stops, and then she weighs the glass and its contents. What should Lisa expect to find about the mass of the glass and its contents when she puts it on a scale?

Answer 1

Answer: Mass is more than 145 g but less than 160 g

Explanation: Acid and limestone reacts forming water, salt and

Carbon dioxide CO2. Because CO2 is gas it is bubbled away from

glass and that's why mass is less than 160 g. Because limestone

releases CO2 and products from acid remain in solution, mass is more than 145 g. If amount of acid in moles is enough, all limestone reacts.

Roughly 44% of mass of limestone CaCO3 forms CO2 and we can estimate mass of gas is 0.44·15 g = 6,6g , so mass would be 153 g