What is the total number of moles in 275 grams of Li2SO4?

Write the empirical chemical formula of calcium with a mass percent of 38.8, phosphorus with a mass percent of 20.0, and oxygen with a mass percent of 41.3.

Predict whether the changes in enthalpy, entropy, and free energy will be positive or negative for the boiling of water, and explain your predictions. how does temperature affect the spontaneity of this process?

The chart shows the bid provided by four contractors to complete a job. which contractor is the most cost-effective?