Learning with Mixture

4.Evaporation🔆🔅♨️♨️
If the solid has dissolved in the liquid it cannot be separated by filtering or centrifuging. Instead, the solution can be heated so that the liquid evaporates completely and leaves the solid behind. The simplest way to obtain salt from its solution is by slow evaporation.
5.Crystallisation🌧️🌨️🧂🧂
In many parts of the world salt is obtained from sea water on a vast scale. This is done by using the heat of the sun to evaporate the water to leave a saturated solution of salt known as brine. A saturated solution is defined as one that contains as much solute as can be dissolved at a particular temperature. When the solution is saturated the salt begins to crystallise, and it is removed using large scoops.

The large intestine
The large intestine has two parts:a the ascending, transverse and descending colona the recturn, where faeces can be stored for about 24 hours before being egested through the a**s during defecation. The colon is wider than the ileum and its ridged lining contains manvmucus secreting cells. There is no digestion in the colon. It has two main functions:
* absorption of mineral salts and water
*preparing faeces for egestion
The remaining undigested food passing from the small into the large intestine contains a lot of water. This is not the water you drink, which is mainly absorbed in the stomach. It is water from all the secretions such as bile and pancreatic juice, that have been added to the food along the alimentary canal. This may be as much as ten litres of water per day. As the contents of the ileum pass through the colon, most of the water is reab-sorbed into the body, so the contents of the colon become firmer. Finally, the undigested food remains, called faeces, enters the re**um where it remains until egested.
Assimilation
Once absorbed into the bloodstream, the molecules produced by digestion are taken by the hepatic portal vein to the liver. The liver processes them invarious ways before they pass to the rest of the body.

The stomach🤰🤰🤰🤰
The stomach is a muscular bag where food eaten during a meal can be stored for processing later by the rest of the gut. When food enters the stomach:starch digestion stops because salivary amylase is denatured by the acid pH in the stomach, and protein digestion begins. Cells lining gastric glands that forms deep pits in the stomach wall secretes several substances:
l. Pepsin, a protease, secreted in an inactive form pepsinogen, catalyse.the hydrolysis of proteins to peptides.
2. Rennin, found in young mammals, converts the soluble protein:,caseinogen, found in milk, into solid casein. Pepsin then digests the casein to produce peptides.
3. Hydrochloric acid reduces the pH in the stomach to a very acid 1.5 - 2.0. This provides the optimum pH for pepsin and rennin, and kills most of the bacteria ingested with food. HCI also creates active pepsin from pepsinogen.
4. Mucus protects the walls of the stomach from the acid and protein-digesting enzymes. If insufficient mucus or too much acid are produced an ulcer can be formed in the wall of the stomach. The mucus also supplies water to mix with the food, dissolving the products of digestion prior to absorption.While in the stomach, the food is churned and mixed by peristalsis, producing chyme, a thick green liquid. The cardiac sphincter at the top of the stomach ensures that no acidic chyme enters the oesophagus. At intervals, small quantities of chyme are squirted through the pyloric sphincter muscle at the bottom of the stomach into the duodenum, the flrst part of the small intestine. Absorption of some substances, for example water and alcohol,also occur in the stomach.