Compounds and Elements Ella paine

Introduction

What are compounds and elements? There are millions of different substances in the world. Some like water, occur naturally. Others, like paper and plastic, are made up in factories. Some substances like sugar and blood, are made by living things. All substances have one important thing in common: they are all made of the tiny building blocks of matter that we call atoms.

How are compunds different to mixtures? A mixture is made from two or more substances that are chemically different. A compound is a substance formed when two or more elements.

Compound
Elements
Mixtures
Limestone

Chemical formula - CaCO3

Wheat elements is limestone made up of? - Calcium carbonate and calcium magnesium carbonate.

Physical properties

Hardness - 3 to 4 on Moh's scale.

Density - 2.5, to 2.65 kg/m3

Compressive strength - 1800 to 2100 kg/mcm2

Water apsorption - Less than 1%

Porosity - Quite low

Weather impact - Resistent

Chemical properties

Lime (Ca0) - 38-42%

Silica (Si02) - 20-25%

Alumina (Al203) - 2-4%

Other oxides like Na, Mg - 1.5 to 2.5%

Loss on ignition (LOI) - 30-32%

What are it's uses and where is it found?

Limestone is used as a building material, and to purify iron in blast furnaces. It is also used in manufacture of glass, and cement.

Earth has many limestone-forming environments. Most of them are found in shallow water areas between 30 degrees north latitude and 30 south latitude.

Limestone caves
Elements your compound is made up of
Chemical symbol, atomic number and atomic mass

Calcium - Ca, 20, 40.078 u ± 0.004 u

Carbon - C, 6, 12.0107 u ± 0.0008 u

Oxygen - O, 8, 15.9994 u ± 0.0004 u

Physical and chemical properties
Calcium

Melting point - 839° C

Boiling point - 1484° C

Density - 1.54 g/cm3

Appearance - Calcium is dull gray, but it is shiny when scratched.

Other physical properties - Calcium is an excellent conductor of electricity. It is very soft and easily scratched.

Chemical properties - Calcium reacts rapidly with air to form a coating of gray oxide, and it burns with a red flame.

Compounds - Compounds of calcium are white in color. One compound is calcium carbonate, which makes up limestone (used in cement manufacture).

Carbon

Melting point - 3550° C

Boiling point - 4827° C

Density - 1.9 g/cm³ (charcoal); 2.3 g/cm³ (graphite, or carbon rod); 3.5 g/cm³ (diamond).

1.9 g/cm³ (charcoal); 2.3 g/cm³ (graphite, or carbon rod); 3.5 g/cm³ (diamond).

Other physical properties - There are three forms of carbon: charcoal, graphite, and diamond (which is the hardest substance known). Each form has different physical properties.

Chemical properties - Carbon combines with oxygen in the air to form carbon dioxide.

Compunds - Carbon forms a wide variety of compounds, many of which are important components in living things. It is present in the compounds found in coal and limestone.

Uses - Charcoal is used in filters to absorb impurities in water or smells from the air. It is also used as a fuel for cooking (for example, in barbeques). Graphite is used as a lubricant and to make pencil leads. Diamond is used in jewelry and in cutting tools (because of its hardness)

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