If a SELECT statement includes an aggregate function (e.g., SUM()), why must all non-aggregated columns in the SELECT list also be present in the GROUP BY clause?

When 2 moles of  Mg3N2 are allowed to react, how many moles of H2O also react?  Mg3N2 + 6H2O → 3Mg(OH)2 + 2NH3

Why is it essential for a primary key to be assigned to a relational table?

The gas with an initial volume of 24.0 L at a pressure of 565 torr is compressed until the volume is 16.0 L. What is the final pressure of the gas, assuming the temperature and amount of gas do not change? 

In a JOIN using ON table1_key = table2_key, what is the typical relationship between these keys in a well-designed schema?

What is the classification for this unbalanced reaction? Fe + HCl –> FeCl3 + H2

1 mol of magnesium chloride, MgCl2 contains ___ moles of chloride ions(Cl-)

Which naming convention is often recommended for table names?

What does the OR operator do in a SQL query?

The temperature of a 500. mL sample of gas increases from 150. K to 350. K. What is the final volume of the sample of gas, if the pressure and amount of gas in the container are kept constant?