DISTINCTION BETWEEN COMPOUNDS AND MIXTURES The following example of iron, sulphur and iron sulphide will make us understand the difference between mixtures and compounds. Properties of Iron and Sulphur The following experiment shows the difference in properties between the elements iron and sulphur. Preparation of a Mixture of Iron and Sulphur Take about […]
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CONSTITUENTS OF MATTER Atoms, Molecules, Elements and Compounds The Atom An atom is the smallest particle of a substance which can have its own characteristic properties. Atoms are built up of even more fundamental sub-atomic particles. These are electrons, protons and neutrons. The protons and neutrons are in the nucleus (centre) of the atom and
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CONDUCTORS AND INSULATORS The ability to conduct electricity is the major simple distinction between elements that are metals and non-metals. Electrical Conductors A conductor is a material that conducts electricity but is not chemically changed in the process. They carry an electric current through freely moving electrons when a potential difference is applied across
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Pure Substance Pure means that only one substance is present in the material and can be a pure element or compound. A simple physical test for purity, and properties that can help identify a substance, is to measure the boiling point or melting point. Every pure substance melts and boils at a fixed temperature.
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CONDUCTORS AND NON-CONDUCTORS All metals (copper, iron, lead, magnesium etc) and graphite, a non-metal. Most non-metals (sulphur, iodine, charcoal etc.) Most solid compounds (All gases are non-conductors) Liquids are classified in three groups as regards their conductivity of electricity: (i) Those that pass an electric current and are not decomposed by if (conductors) (ii)
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COMPOUNDS AND THEIR PROPORTIONS All elements are represented by a chemical symbol. It is either a single capital letter, or a capital letter followed by a small letter. Examples: Ca = calcium Cu = copper C = carbon N = nitrogen Combinations of symbols represent compounds. These compounds are called chemical formulas. Example: H20 2
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MATTER Matter is: Anything that has mass and occupies space (has volume) Composed of particles (molecules, ions, atoms). These are in constant motion attracting one another with inter-particle forces (or cohesive) Is a solid, liquid or gas depending on interparticle forces of attraction and spaces between particles. Matter has many properties. It can have
CLASSIFICATION OF SUBSTANCES Matter Matter can be classified as either a mixture or a pure substance. Mixtures contain at least two substances. If you can see the different parts of the mixture it is called a mixture.E.g. Soil and concrete Properties of mixtures depend on the proportions of the parts. Have you ever made
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Which apparatus? You wouldn’t dream of trying a chicken using a spoon, or of drying your hair in over a stove! In everyday life, we need to use the right tools for the job we are doing. The same is true in the science lab. There are lots of types of different chemical apparatus, all
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SCIENTIFIC METHOD The scientific method is a set of ideas or a procedure that scientists use to investigate things they want to understand. By using the method, you can be sure you’re carrying out your project correctly. The scientific method allows you to investigate an experiment in a step-by-step method. Problem: What are you going
Safety rules and regulations Your school science laboratory is set up so that you can perform science experiments in safety provided that you follow the proper procedures and safety precautions listed below. Your teacher will give you specific information about the safety routines used in your school. It is essential for all concerned that certain
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INTRODUCTION TO CHEMISTRY Welcome to Chemistry, the Science concerned with the study of matter. In simplest terms, chemistry is the science of matter. Anything that can be touched, tasted, smelled, seen or felt is made of chemicals. Different thing feel, taste, smell and appear differently- like t fresh vegetables. If you are blindfolded and
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