During a science lab investigating chemical reactions, Mr Grace students place an antacid tablet in a ziplock bag. They recorded the mass of the tablet, 25 g, in the bag, 60 grams. Then they carefully added 50 g of water and quickly seal the bag. The tablet began at this and soon disappeared. The bag was filled with gas. If the total mass of the bag+tablet+water was 135 grams before the reaction, what was the total mass of the bag+liquid+gas after the reaction was completed? A) 60 grams B) 75 grams C) 135 grams D) 270 grams

Option - C (135 grams) is the correct answer.

Explanation:

In this experiment the students took tablet of an antacid which when added to water decomposes and produces many products among which some are in gas form. Now, as stated the ziplock bag is quickly sealed after the addition of tablet so it means nine of the gas produced is allowed to escape from the bag.

Therefore, according to law of conservation of mass the mass can neither be created nor destroyed. So, in this experiment there will be no increase in mass because the mass cannot be created and also, there will be no decrease in mass because it can neither be destroyed. So, we will assume that the gas produced is not allowed to escape hence, the total mass of the system (i. e. bag, water, products) will remain the same as they were before the reaction.