chemistry solution.pdf

2024 Paper 1 Uganda Certificate of Education CHEMISTRY New Lower Secondary Curriculum SCORING GUIDE UGANDA NATIONAL EXAMINATIONS BOARD © 2024 Uganda National Examinations Board Turn Over 545/1 CHEMISTRY Paper 1 2 545/1 - CHEMISTRYDRAFT GUIDE / BASIS S/N | Basis of Assessment | Assessment Criteria | Scoring | A. | CATEGORY / TYPE | Onyera used a soapy detergent (or soap) instead of a soapless detergent. | 02 | B. | FUNCTIONS OF PRODUCTS (How It Works) | - The dirt is held on the cloth by a layer of oil. - Detergents (soaps) facilitate the emulsification and removal of grease / . Alternatively - Detergents facilitate breakdown of fats into small parts. - A soap molecule contains two parts; namely; the water-soluble /polar carboxylate head / hydrophilic end or lipophobic head and non-polar tail/fat- soluble part / hydrophobic part/lipophilic part. -During washing, soap acts by lowering the surface tension between water and oil/grease/other water insoluble materials and also emulsifies them. The hydro-carbon tail becomes attached to dirt /oil /fat while the polar head dissolves in water. With constant agitation, the dirt is pulled off the cloth and gets dispersed in water as tiny droplets which are then poured away. The cloth is then rinsed several times and dried. | 02 | C. | DANGERS OR SIDE EFFECT OF PRODUCTS. | (a) Soap contains chemicals that can cause:  Skin burns / blisters / irritation and hence pain or cancer. | 03 Section A Item 1. bloom/alagalbloom and hence water N.B.