A tank contains 250 L of argon gas. The pressure is 8790 kPa and the temperature is 23*C. How many moles of argon are in the tank?

The density of glycerin is 1.26grams/centimeter cubed . how many is this? use the conversion rates of and . express your answer to the correct number of significant figures.

An atom of sodium-23 (atomic number = 11) has a positive charge of +1. give this information, how many electrons does it have? how many proteins and neutrons does this atom have

8.98 dm3 of hydrogen gas is collected at 38.8 °c. find the volume the gas will occupy at -39.9 °c if the pressure remains constant.