How many moles of solute are dissolved in 400. mL of a 0.200M solution

In a popular classroom demonstration, solid sodium is added to liquid water and reacts to produce hydrogen gas and aqueous sodium hydroxide. part a write a balanced chemical equation for this reaction. express your answer as a chemical equation. identify all of the phases in your answer.

Acamcorder has a power rating of 17 watts. if the output voltage from its battery is 7 volts, what current does it use?units:

Mary is conducting an experiment on how pollution affects plant growth. how can she ensure that her data are reliable?