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Elements, compounds and mixtures. What is an element?. An element is…. material made of just one type of atom A substance that can not be separated or broken down into simpler substances by chemical means. What are the 3 most abundant elements that make up the earth?. answer. Oxygen Iron
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An element is… • material made of just one type of atom • A substance that can not be separated or broken down into simpler substances by chemical means
What are the 3 most abundant elements that make up the earth?
answer • Oxygen • Iron • silicon
answer • Oxygen • Carbon • hydrogen
atom • The smallest unit of an element that maintains the properties of the element
Compound • A substance made of two or more different elements that are combined chemically • Properties of compounds may not be the same as properties of elements that make them up
Compounds • Substances composed of 2 or more elements that have been chemically combined • Glass • Sugar • Water • Salt
compounds in real life • My gold ring • Water in a bottle • Metal cart • Copper wiring
Elements in real life • Neon lights • 24 Karat gold bar • Oxygen in a scuba tank
Molecule • The smallest amount of a compound that still retains the qualities of the compound • 1 molecule of water is composed of 2 hydrogen and 1 oxygen atom
Sugar molecule: Made up of atoms combined in a specific way Oxygen atoms are red, gray Carbon atoms are white Hydrogen are small white with red dots
Comparisons and contrasts • Element and compound • Comparison: Both are pure substances • Contrast: Elements can only be composed of one type atom, Compounds are composed 2 or more types atoms (elements)
Atom and Molecule • Comparison: The smallest unit that still retains material’s properties • Contrast: Atom is the smallest unit of an element, Molecule is the smallest unit of a compound. Molecules can be composed of different types of atoms
What does it mean to be a pure substance? “100% pure Honey” “100% pure salt or sugar”
Pure substance • Substance composed of either a single type of element or compound chemically combined • If a Compound, a pure substance has a fixed composition or proportions of elements • every molecule of water has 2 hydrogen and one oxygen atom • All compounds can be written with a chemical formula
Pure Substance • An amount of matter , either single element or one compound that exhibits distinct chemical and physical properties • Table Salt (if just made with NaCl) is a pure substance • Grape Juice is not (Water, Sugars, Vitamins)
Mixture • A combination of 2 or more pure substance combined physically • Classified by how thoroughly they are mixed • Properties of mixture similar to properties of components
Mixtures • If you can separate the substances, it’s a mixture • If it has ingredients, it’s a mixture
Types of Mixtures • Heterogeneous • Homogeneous • Miscible • Immiscible • Alloy
Heterogeneous mixture • Mixtures with ingredients that do not mix well or stay mixed long • Examples: Chocolate syrup and milk
Homogeneous Mixture • Mixtures that mix very well • Solutions where substances dissolve well into each other • Can not visually see any separation of the ingredients • Examples: Gasoline, Soda
Pure substance and mixtures • Comparison: both are composed of elements • Contrast: Pure substance is composed of an element or compound whose composition is fixed. Mixture is composed of a combination of pure substances whose composition can vary
What is the difference between heterogeneous and homogeneous mixtures?
Heterogeneous and homogeneous mixtures • Comparisons: both mixtures • Contrast: Heterogeneous materials do not mix well or evenly. They are easily separated. Homogeneous mixtures do mix well and evenly, not easily separated
Difference… • Heterogeneous mixtures: are mixtures of 2 or more substances that are not completely soluble (bits of each are seen in mixture) • Homogeneous mixtures: are mixtures of 2 or more substances that are completely soluble (blend completely, can not tell components)
Miscible mixture • Extremely homogeneous • Dissolves completely • Example: Air
Miscibilitity • How well substances mix together • The greater the ability to mix (solubility), the more miscible it is. • Oil and water are immiscible (insoluble) • Carbon dioxide and water (very soluble)
Immiscible mixture • Extremely heterogeneous • Don’t mix well at all • Examples water and granite
Immiscible Mixture Gasoline, Soda
Solubility • Measurement of the ability of one substance (solute) to dissolve into another substance (solvent)
Alloy • An alloy is a solid homogenous mixture of two or more metals. • The there is not chemical reaction occurring, and the original materials can be recreated by melting. • There are thousands of different alloys, and people use them for many different purposes.