Blog

Atomic orbitals are energy waves, they are the standing ener…

Atomic orbitals are energy waves, they are the standing energy waves that are produced as a results of confining the waves in space, applying a boundary condition. It is a bit hard to actually “see” them as waves because they are 3-dimensional and have boundary conditions that are hard for us to visualize. Nevertheless, they are the allowed stationary waves of the electron system. The problem is that we have to just “accept” what the allowed weaves are, we can’t really predict the shapes that would be allowed or not allowed. Standing water energy waves are easier to understand and “see”. If the boundary condition for a body of water is enclosing it in a tank of fixed length, then allowed standing water energy waves are formed that are easier to understand, and it is easier to see which would be allowed and which not allowed. Below are drawings of some representative water waves. Which of these are allowed as standing waves as a result of the enclosure boundary condition?

The temperature rises from 25.00°C to 29.00°C in a bomb calo…

The temperature rises from 25.00°C to 29.00°C in a bomb calorimeter when 3.50 g of sucrose undergoes combustion in a bomb calorimeter. Calculate ΔErxn for the combustion of sucrose in kJ/mol sucrose. The heat capacity of the calorimeter is 4.90 kJ/°C. The molar mass of sugar is 342.3 g/mol. (10 pts)

A sample of hydrogen collected by displacement of water occu…

A sample of hydrogen collected by displacement of water occupied 30.0 mL at 24.0°C on a day when the barometric pressure was 736 torr. What volume would the hydrogen occupy if it were dry and at STP? The vapor pressure of water at 24.0°C is 22.4 torr.  (10pts)