A chemical change affects on the molecular level of matter, which makes it irreversible. Combustion is a pretty good exmple. Physical changes are reversible and dont alter the formula. Hope this helped!
1. At constant tempaerature and pressure, 3 tablets produce 600cm^3 of gas
Thus calculating for 1 tablet that produces 600 / 3 = 200 cm^3
So now two tablets produce 200 x 2 = 400 cm^3
2. We have the equation PV = nRT, n being the number of moles
Pressure P = 1,000 kPa
Volume V = 3 L
R = 8.31 L kPa/mol-K
Temperature T = 298 K
n = PV / RT = (1000 x 3) / (8.31 x 298) = 3000 / 2476.38 = 1.21 moles
Number of moles = 1.21 moles.
Use mv=mv, plug in the know 1x9.24=3m. Solve for m, which m is 3.08M
Well. Depends.
You plan on doing a school project?
You should try baking soda and vinegar, almost everyone knows about this.
Orr you can use mentos and soda.
Or for fun, just get a watermelon or any fruit and use rubber bands all around it until it goes BOOM!
Hope this helps :D