Chemistry

  Unit: 1 History of a Nation   Lesson: 1 Prophet Mohammad (PBUH) Page 7   Lesson: 2 The Beginning of Islam 11   Lesson: 5 The Ayyubid Empire Page 22 Lesson: 5 The Ayyubid Empire Page 23 Lesson: 5 The Ayyubid Empire Page 24 Unit: 2, Individual Differences   Lesson: 1 What is a Phobia? Page 34    Lesson: 2 Feeling of Anxiety Page 38  

  Emulsions: An emulsion is a finely dispersed mixture of two or more liquids that do not dissolve in each other. Emulsifiers: Salad cream also contains oil and water. Salad cream has egg yolk added. This keeps the oil droplets mixed with the water. It stops the oil and water separating out into layers. A substance that does this is called an emulsifier . Detergents: Many detergents are made from the products of crude oil. Washing-up liquid is an example. Detergents are substances which help the cleaning action of water. Water is good at dissolving many things. However, it cannot dissolve oil or grease. This is where detergents help. They act as emulsifiers . They remove grease and keep it dispersed in water. Soaps: We can summaries the reaction as: Oil/fat   +   sodium hydroxide   à   soap   +   glycerol Making soap is called saponification . Preservatives and anti-oxidants: Fresh foods soon ‘go off’ as they are attacked by ba...

  Grade 7    Chemistry                                                                      Question 1                   The particles move from an area of low concentration to an area of high concentration is called diffusion. F Molecules are groups of 2 or more atoms bonded together. T Elements contain only one type of atom. T Compounds contain 2 or more types of atom. T Chemists use a kind of short-hand to describe molecules. It's called the symbol. F Question 2                   The particles move f...

    Skeletal system   The human  skeletal system  consists of all of the bones, cartilage, tendons, and ligaments in the body.     The  skeletal system  includes all of the bones and joints in the body. Humans are vertebrates, animals having a vertebral column or backbone. Muscular system   The muscular system is  composed of specialized cells called muscle. Muscles, attached to bones or internal organs and blood vessels, are responsible for movement. The  muscular system  is responsible for the movement of the human body. Attached to the bones of the skeletal system .                  

  Plant Oil Chapter#14 Oils in plants: Like animals, plants also store excess energy they take in as chemical energy in fats. The fats in plants are often liquids at 20 o C so we call them oils. Extracting the oil from plants: In order to get the oil from a plant, we have to break open its cells to release it. There are two main ways to break down the cell walls: Pressing (applying pressure) Distillation (heat using steam) Then water and other impurities are removed. Pressing: ´   In this method we squash the plant material. Then we collect the liquid. The oil and the water-based solutions are immiscible. ´   They do not dissolve in each other and will separate out into two layers. ´   Then the oil and water are separated by centrifuging (spinning the mixture at high speeds) or just by decanting (pouring off). Distillation: To extract plant oils we can either: ´   Boil up the plant material with water, or ´   P...

  Symmetrical: A shape has symmetry if a central dividing line (a mirror line) can be drawn on it, to show that both sides of the shape are exactly the same. Asymmetrical: The meaning of  ASYMMETRICAL  is having two sides or halves that are not the same, not symmetrical.  Having parts that fail to correspond to one another in shape, size, or arrangement Bilateral symmetry: Bilateral symmetry  refers to organisms with body shapes that are mirror images along a midline.    

Grade 7 Chapter 7 Electrolysis  Class Assessment 1.       Loss of electron by an atom is called ………….? Oxidation                      b.  Reduction         c. Redox  reaction 2. In ………… state of electrolytes, ions are not free to move? Liquid                            b. Solid                  c. Gas 3. Compounds that do not conduct electricity even in molten or solution form are called ……………….. ? a. Electrolytes   b. Metal Electrode    c. non-Electrolytes     4.   Lead, Pb 2+ , gains -------- electrons forming lead atoms.     a)    2      ...