Mindblown: a blog about philosophy.

A piston performs work of 210. L atm on the surroundings, while the cylinder in which it is placed expands from 10. L to 25 L. At the same time, 45 J of heat is transferred from the surroundings to the system. Against what pressure was the piston working?

The enthalpy of combustion of CH4(g) when H2O(l) is formed is 891 kJ/mol and the enthalpy of combustion of CH4(g) when H2O(g) is formed is 803 kJ/mol. Use these data and Hess’s law to determine the enthalpy of vaporization for water.

Solid thorium(IV) fluoride has a boiling point of 1680C. What is the density of a sample of gaseous thorium(IV) fluoride at its boiling point under a pressure of 2.5 atm in a 1.7-L container? Which gas will effuse faster at 1680C, thorium(IV) fluoride or uranium(III) fluoride? How much faster?

Helium is collected over water at 25C and 1.00 atm total pressure. What total volume of gas must be collected to obtain 0.586 g of helium? (At 25C the vapor pressure of water is 23.8 torr.)

A piece of solid carbon dioxide, with a mass of 7.8 g, is placed in a 4.0-L otherwise empty container at 27C. What is the pressure in the container after all the carbon dioxide vaporizes? If 7.8 g solid carbon dioxide were placed in the same container but it already contained air at 740 torr,…

Given that a sample of air is made up of nitrogen, oxygen, and argon in the mole fractions 78% N2, 21% O2, and 1.0% Ar, what is the density of air at standard temperature and pressure?

A compound has the empirical formula CHCl. A 256-mL flask, at 373 K and 750. torr, contains 0.800 g of the gaseous compound. Give the molecular formula.

Hydrogen cyanide is prepared commercially by the reaction of methane, CH4(g), ammonia, NH3(g), and oxygen, O2(g), at high temperature. The other product is gaseous water. a. Write a chemical equation for the reaction. b. What volume of HCN(g) can be obtained from 20.0 L CH4(g), 20.0 L NH3(g), and 20.0 L O2(g)? The volumes of…

A student adds 4.00 g of dry ice (solid CO2) to an empty balloon. What will be the volume of the balloon at STP after all the dry ice sublimes (converts to gaseous CO2)?

At room temperature, water is a liquid with a molar volume of 18 mL. At 105C and 1 atm pressure, water is a gas and has a molar volume of over 30 L. Explain the large difference in molar volumes.