Calculate the mass of nacl needed to make 40% solution from 3kg of water ? could you explain step by step : -)

There is an area in idaho named craters of the moon where most of the ground is covered with basalt, adark gray, igneous rock with no visibl crystals. what can you infer about the geographical history of the area?

The empirical formula of a compound is ch2o and its mass is 120 amu/molecule, what is its formula?

Which elements are found in glucose, the product of photosynthesis? a. carbon, hydrogen, and oxygen b. carbon and hydrogen c. carbon, nitrogen, and oxygen d. hydrogen, nitrogen, and carbon