A student had a sample of (BaCl2.2H2O) and an inert material. He heated a sample until the mass did not change. From this data, calculate the percentage of (H2O)
Mass of crucible + cover = 26.39 g
Mass of crucible + cover + unknown sample = 28.20 g
Mass of crucible + cover + residue = 28.03 g

he uptake of drugs from the intestine is often strongly influenced by diffusion. for example, consider a water-insoluble steroid for treating inflammation that is solubilized in aggregates of detergent molecules, called micelles. these micelles, aggregates of 80 soap molecules, have a molecular weight of 24,000, a diameter of 2.6 nm, and a charge of -27. the positively charge ions (counterions) in this system are na".

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.