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.
Apple's iPad Pro is the biggest -- literally -- and boldest attempt to reinvent what the iPad fundamentally is and can be. It has a nearly 13-inch screen. Some new inputs and accessories, like a super-accurate stylus called the Pencil, and a new side connector for keyboards.