Properties of water equal to that of the hydrogen ion (), which gives a pH of 7 at 25 °C. Action of water on rock over long periods of time typically leads to weathering and water erosion, physical processes that convert solid rocks and minerals into soil and sediment, but under some conditions chemical reactions with water occur as well, resulting in metasomatism or mineral hydration, a type of chemical alteration of a rock which produces clay minerals. It also occurs when Portland cement hardens. Water ice can form clathrate compounds, known as clathrate hydrates, with a variety of small molecules that can
Water crisis in the Democratic Republic of the Congo Kivu. Furthermore, funding is heavily skewed towards the city of Kinshasa, receiving almost 40 percent of total investments in the urban water sector. The majority of the DRC's population without access to safe drinking water lives in rural areas. The rural water sector of the DRC has been neglected for many years and is characterized by a deteriorated infrastructure due to lack of maintenance and spare parts. Furthermore, many water systems are of poor construction quality. The major source of rural water supply are springs, accounting for approximately 90 percent of the total rural water supply. Springs have the advantage