Iam stumped.
during a physical science lab investigating chemical reactions, several students placed a 30g antacid tablet in a 30g zip-lock bag. 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. if the mass of the liquid after the reaction is completed is still 50 grams, how much gas is produced?

a) 30 grams
b) 50 grams
c) 80 grams
d) 90 grams

The human body stores chemical energy from digested food. some of the chemical energy is converted into mechanical energy when the body moves. which statement best supported by this information

As part of an industrial process, air as an ideal gas at 10 bar, 400k expands at steady state through a valve to a pressure of 4 bar. the mass flow rate of air is 0.5 kg/s. the air then passes through a heat exchanger where it is cooled to a temperature of 295k with negligible change in pressure. the valve can be modeled as a throttling process, and kinetic and potential energy effects can be neglected. (a) for a control volume enclosing the valve and heat exchanger and enough of the local surroundings that the heat transfer occurs at the ambient temperature of 295 k, determine the rate of entropy production, in kw/k. (b) if the expansion valve were replaced by an adiabatic turbine operating isentropically, what would be the entropy production? compare the results of parts (a) and (b) and discuss.

*drag each tile to the correct location in the sequence* the table shows chronological events in the life of our sun, a medium-sized star. place the missing events into the correct rows of the table.