Question

during a physical science lab investigating chemical reactions, several students placed a 30g antacid tablet in a zip - lock bag that has a mass of 20g. they recorded the masses of the tablet and the bag. then they added 50 grams of water and quickly sealed the bag. the tablet began to fizz and soon disappeared. the bag was filled with gas. what can you conclude about the amount of gas produced if the mass of the liquid after the reaction is completed is 80 grams? a 30 grams b 50 grams c 10 grams d 20 grams

Explanation:

Step1: Identify initial and final masses

Initial mass of tablet + bag + water = 30 g (tablet)+ 20 g (bag)+ 50 g (water)=100 g.

Step2: Use law of conservation of mass

According to the law of conservation of mass, the total mass before the reaction is equal to the total mass after the reaction in a closed - system. Let the mass of gas be $m$. The final mass of the liquid and remaining substances is 90 g. So, 100 g=90 g + $m$.

Step3: Solve for mass of gas

$m = 100 - 90=10$ g. But this is not in the options. We assume the question is asking about the mass change which is 100 - 90 = 10 g. If we consider the options in terms of the gas produced, we know that the mass lost from the system (to form gas) is 10 g. Since the total mass before was 100 g and after was 90 g, the mass of gas produced is 10 g.

Answer:

C. 10 grams