What is the percentage by mass of sodium in sodium hydroxide (Na=23,O=16,H=1)​

Select all the correct answers. which compounds have the empirical formula ch20? (multiple answers)a. c2h4o2b. c3h603c. ch2o2d. c5h1005e. c6h1206

In order for a high temperature boiler or steam engine to produce superheated water, or steam: the heat source must be greater than 100°c the water must be permitted to evaporate quickly the system must be sealed and become pressurized above atmospheric pressure the vapor pressure must be kept below 760 mm(hg)

The image below shows a weather service map.. i’m not sure if is correct