Which task most likely involves a calculation that uses moles?

A student left a sealed jar of water outside her home. Water can be a solid, liquid, or gas. When she put it outside, the water was a solid. Twelve hours later, the water had changed phase and was a liquid. What happened to the water molecules?1.

Determine the pH of a 0.28 M solution of pyridinium nitrate (C5H5NHNO3) at 25°C. [Pyridinium nitrate dissociates in water to give pyridinium ions (C5H5NH+), the conjugate acid of pyridine (Kb = 1.7 * 10-9), and nitrate ions (NO3-).]

Why do atoms have different isotopes?

Read the scenario. A lizard is at an initial position of 2 m and walks to a position of 10 m in 4 s. What is the lizard's average velocity? 2.5 m/s -3 m/s 2 m/s 3 m/s

What is the formula for aluminum oxide

A student noticed while doing the neutralization experiment that the calorimeter kept getting warmer. how would this error affect the final calculation for the δhneut of each reaction? would it be overestimated, underestimated or remain unaffected?

A solution contains 45 grams of nitrogen gas and 40 grams of argon. What is the mole fraction of argon in this solution?

How is an animal cell related to tissue and organs

Predict the precipitate produced by mixing an Al (NO3) 3 solution. write the net ionic equation for the reaction. include the states of matter

Identify the precipitate (if any) that forms when KOH and Cu (NO3) 2 are mixed