Classification of Matter Physical Science Mixtures elements compounds

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Classification of Matter Physical Science

Classification of Matter Physical Science

Mixtures, elements, compounds n n n Scientists like to classify things. One way that

Mixtures, elements, compounds n n n Scientists like to classify things. One way that scientists classify matter is by its composition. Ultimately, all matter can be classified as mixtures, elements and compounds.

Why isn’t it a good idea to classify matter by its phases? n Because

Why isn’t it a good idea to classify matter by its phases? n Because one kind of substance can exist in more than one phase – such as H 20. And matter changes phases rather easily.

Why isn’t matter classified according to its physical characteristics, such as color? n Scientists

Why isn’t matter classified according to its physical characteristics, such as color? n Scientists wouldn’t find it very useful to group gold, sunflowers, and the sun together.

Classifying Mixtures

Classifying Mixtures

Classifying Mixtures • Solutions – Appear Uniform – Mixed particles are dissolved and so

Classifying Mixtures • Solutions – Appear Uniform – Mixed particles are dissolved and so small that they don’t reflect light (scattering). – Nothing settles out over time. – Nothing filters out. – Can be in solid, liquid, or gas form!

Examples of homogeneous mixtures Milk, toothpaste, and mayonnaise are homogeneous mixtures.

Examples of homogeneous mixtures Milk, toothpaste, and mayonnaise are homogeneous mixtures.

Classifying Mixtures

Classifying Mixtures

Heterogeneous mixtures You can see the particles that make it up. n n n

Heterogeneous mixtures You can see the particles that make it up. n n n Sand pebbles Oil and water Cereal

Granite is a heterogeneous mixture.

Granite is a heterogeneous mixture.

Classifying Matter Heterogeneous • Colloids – Looks uniform but particles aren’t really dissolved. Particles

Classifying Matter Heterogeneous • Colloids – Looks uniform but particles aren’t really dissolved. Particles are still large enough to scatter light. Looks cloudy when light goes through it. • Suspensions – Don’t look uniform, filters, settles out over time, and particles scatter light.

Classifying Matter • What are examples of mixtures that are – – – Liquid/solid

Classifying Matter • What are examples of mixtures that are – – – Liquid/solid Liquid/liquid Liquid/gas Solid/solid Gas/gas

Pure Substances

Pure Substances

Pure Substances Elements & Compounds • ELEMENTS: are the elements on the periodic table,

Pure Substances Elements & Compounds • ELEMENTS: are the elements on the periodic table, they are not mixed together, they are pure. Au (gold)

Elements All elements are made of atoms. Atoms of the same element are alike.

Elements All elements are made of atoms. Atoms of the same element are alike. Atoms of different elements are different.

Pure Substances Elements & Compounds: 2 or more elements combined (chemically bonded) to make

Pure Substances Elements & Compounds: 2 or more elements combined (chemically bonded) to make a substance. Na. Cl (salt)

Compounds are also pure substances. But compounds are made from more than one element.

Compounds are also pure substances. But compounds are made from more than one element. Water is a compound. Water can be broken down into simpler substances – hydrogen and oxygen.