Matter combines to form different substances LESSON 1
Matter combines to form different substances. LESSON 1. 3
Matter can be pure or mixed. Most of the substances you see around you are mixed substances. Ex: the air you breathe wood paper steel lemonade all of these are mixed substances.
Matter can be pure or mixed. A pure substance has only one type of component. Pure silver only contains silver atoms. Pure water contains water atoms, which are a combination of hydrogen and oxygen molecules.
Matter can be pure or mixed Does the presence of two types of atoms mean that water is not a pure substance after all? A substance is considered pure if it only contains a single type of atom or a single combination of atoms that are bonded together. Hydrogen and oxygen are bonded together as molecules, water has nothing in it so it is considered a pure substance.
Think about it… A pure substance has only one type of component. Which of the following a pure substance ? a)Seawater b)Bread c)Table salt d)Soil from a garden
Elements One type of pure substance is an element. An element is a substance that contains only a single type of atom. You cannot separate an element into other substances.
Compounds A compound is a substance that consists of two or more different types of atoms bonding together. Ex: Water > H 2 O Carbon Dioxide > CO 2 Ammonia > NH 3 Sugar > C 6 H 12 O 6
Mixtures Most of the matter around you is a mixture of different substances. A mixture is a combination of different substances that remain the same individual substances and can be physically separated.
• Mixtures can be separated by physical means. If you don’t like cucumbers, you separate them by picking them out.
Explain how mixtures are different from a compound. • A compound is made of two or more elements that are joint chemically. You can’t separate them easily. • A mixture is made of elements or compounds that are not combined chemically. You can separate them easily.
Comparing Mixtures and Compounds Mixtures The substances in mixtures remain the same substance. Mixtures can be separated by physical means. The portions of different substances can vary throughout each mixture. Compounds are new substances formed by atoms that bond together. Compounds can be separated only by breaking the bonds between atoms. The proportions of different substances in compounds are fixed because the type and number of atoms that make up the compound are always the same.
Parts of mixtures can be the same or different throughout. There are two different types of mixtures Heterogeneous: when you can see the different properties in the mixture Homogeneous: when substances are evenly spread throughout a mixture you cannot tell one part from another.
Mixtures are two kinds: • Heterogeneous = different throughout. • Homogeneous = same through out.
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