Identify each event as the result of mechanical weathering or chemical weathering. Please help :(

1) organisms such as barnacles and snails attach themselves to rocks and release acids that dissolve the rock surface
2) rocks disintegrate into smaller pieces after ice wedges create openings for them
3) water cause granite rocks to break down into clay and salt
4) groundwater forms underground caves as it dissolves limestone
5) deep valleys are carved into mountains as a result of glaciers
6) oxygen in the atmosphere turns rocks a reddish-orange color