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
Two Songs to be sung of a summer night on the water songs and other works by Delius with choral music by Arnold Bax. Two Songs to be sung of a summer night on the water Two Songs to be sung of a summer night on the water, Op. 91, were composed by Frederick Delius in 1917. He set the wordless works for choir a cappella. The songs were published in 1920 and first performed in 1921. Delius composed the songs at Grez-sur-Loing in 1917. He set them for six-part choir, SATTBB, without words, but vocalises on the syllable "uh". The first song is marked "slow but not dragging", the other which