Acids The chemicals causing sourness of substance, is called acids . These are not soapy to touch. These turn blue litmus into red. Example- Acetic acid(chemical in vinegar) Bases The chemicals causing bitterness of substance, is called bases . These are soapy to touch. These turn red litmus into blue. Example- baking soda, calcium hydroxide etc. Indicator The substance used to test whether a substance is acidic or basic, are called indicator. Example- Turmeric, litmus, china rose petals, phenolphthalein etc. Litmus:A natural dye It is a natural indicator. It is extracted from lichen. When added to acid, it turns red. When added to base, it turns blue. Available in- Solution form, Paper strips Neutral solution The solution which donot change the colour of either red or blue litmus, is known as neutral solution. Example- Sugar solution, water etc. China rose as indicator China rose indicator t...
Materials: Metals and Non-metals * Lustre - Lustre is physical property of substance by which it looks shiny. * Malleability - Malleability is property of metal, by which they can be beaten into thin sheets. * Ductility - Property of metal, by which they can be drawn into wires, is called ductility. * Good conductor of heat/electricity -The materials through which heat/electricity can pass, is called good conductor of heat/electricity. -Example- Iron. * Poor conductor of heat/electricity -The materials through which heat/electricity cannot pass, is called poor conductor of heat/electricity. - Example- Plastic * Sonorous - Metals are sonorous since they produce ringing sound. * Physical properties of metals and Non- metals ...
NCERT CBSE Class 7 Chapter 2 Exercise Solution Nutrition in Animals NCERT Class VII Chapter-2 1. Fill in the blanks: (a) The main steps of nutrition in humans are __________, __________,__________, _________ and __________. Answer- Ingestion, digestion, absorption, assimilation, egestion. (b) The largest gland in the human body is __________. Answer- liver. (c) The stomach releases hydrochloric acid and ___________ juices which act on food. Answer- gastric (d) The inner wall of the small intestine has many finger-like outgrowths called _________. Answer- Villi. (e) Amoeba digests its food in the ____________ . Answer- Food vacuole. 2. Mark ‘T’ if the statement is true and ‘F’ if it is false: (a) Digestion of starch starts in the stomach. (T/F) Answer- F Correct statement- Digestion of starch starts in the mouth. (b) The tongue helps in mixing food with saliva. (T/F) Answer- T (c) The gall bladder tempora...
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