WHAT IS THE DIFFERENCE BETWEEN A LETTER AND AN ALPHABET?​

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

Calculate the molar mass of aluminum oxide (al2o3). express your answer to four significant figures.

In an effort to address concerns about global warming, a power plant in portland,oregon is designed to take all of its exhaust gases from its boilers and recycle the co2 using the solvay process to make sodium hydrogen carbonate. the reaction is shown below. nh3(g) + h2o(l) + co2(g) + nacl(aq) → nahco3(aq) + nh4cl(aq) how many liters each of nh3 and co2 (both at stp) would be consumed to produce 3.00 kg of sodium bicarbonate? the volume of both nh3 and co2 would be