How many moles of sodium chloride (nacl) solute are in 155 grams of an 85.5 percent by mass solution?

When a spring is compressed, the energy changes from kinetic to potential. which best describes what is causing this change?

To find the enthalpy of a reaction in the lab, you measured the of the reactants and the change during the reaction.

Which of these statements best explains why space exploration should be encouraged? it prepares humans to live without oxygen. it dispel myths about objects in space. it prevents comets and asteroids from striking earth. it creates technology to absorb harmful radiations in space.