Science Summative Exam PDF

Science Summative exam Chapter 5, Changes in matter Matter can go through changes, changes can be physical or chemical. When a substance undergoes physical change it can return to its original form. Physical changes don’t produce new substances. A mixture is formed when 2 or mo...

Science Summative exam Chapter 5, Changes in matter Matter can go through changes, changes can be physical or chemical. When a substance undergoes physical change it can return to its original form. Physical changes don’t produce new substances. A mixture is formed when 2 or more substance are added together and the properties don’t change. When a solid dissolves in liquid, the particles of the solid are evenly mixed with the particles of the liquid, it forms a homogeneous solution. Homogeneous means you can’t tell the difference between salt and water (for example) The substances that dissolve in liquid is called solute. The liquid in Which the solute dissolves in is called a solvent, when mixed together is called solution. Suspension is when substances don’t mix eg. oil & sand & water. Changes In matter are examples of physical changes. Eg. when ice is taken out of the freezer for sometime, it melts to become liquid, when we freeze water it becomes ice. If you can see the solute can be visible It doesn’t dissolve. The temperature at which a substance changes from its liquid state to its Solid state is called the freezing point. Water’s freezing point is 0°C. Temperature, wind, and area of exposed surface are some factors that affect the rate of evaporation. Evaporation increases with an increase in wind speed.When a substance undergoes chemical changes, it can’t go back to the original form. It can cause the properties to change. When we boil raw egg. It hardens. It can’t change back to a raw egg. Rust is Formed. When iron reacts with air, and water. We can remove rust but we can’t change it. Effects of changes Eg. Changes in colour, formation of bubbles, formation of precipitate, Precipitate =cause (a substance) to be deposited in solid form from a solution. Changes in temperature