The enthalpy change that accompanies a reaction is called the enthalpy of reaction (DHrxn). It is sometimes convenient to provide the value for DHrxn along with the balanced chemical equation for a reaction (also known as a thermochemical equation): 2H2(g) + O2(g) -> 2H2O(g) DH = -483.6 kJ.
It is the most recent in 9.7 inch iPad version. The display is also Retina with a huge resolution of 2048 x 536 pixels at 264 ppi. This new iPad retained the size 9.7 inches display size(250 mm) and also the LED back-lighting technology, plus fingerprint and scratch resistant coating. Random Access Memory is also the same: 1024 MB DDR II. The 4th generation iPad has the fastest processor, called Apple A6X. CPU features a 1.4 GHz dual core.
The iPad Mini has a 7.9-inch screen. The original iPad Mini had a 1024x768 screen resolution, but all other iPad Minis have a Retina Display with a resolution of 2048x1536. This resolution combined with the 7.9-inch screen measured diagonally gives the iPad Mini a pixels-per-inch (PPI) of 326.