Make both of your hands into fists. Put your closed fists together then pull them apart. Nothing holds your hands together, so it’s easy to pull them apart.
Now link your fingers together. Curl them around one another and pull. It’s hard to pull your hands apart. Linking your fingers is like a chemical reaction.
MIXING CHEMICALS
A chemical reaction can happen when you mix two or more chemical elements together. A chemical element is made of only one kind of atom. There are more than 100 different kinds of atoms. Atoms are much too small to see.
Atoms that make up chemical elements link together in chemical reactions. A chemical reaction makes a new kind of chemical substance. The new substance is different from the chemicals that made it. Chemists use chemical reactions to make all kinds of substances. They have made millions of new substances, including many kinds of plastics and medicines.
ATOMS AND MOLECULES
Atoms link up to make molecules. A molecule has two or more atoms. Chemical reactions make new molecules.
Oxygen atoms take part in many chemical reactions. Oxygen and hydrogen atoms link up to make a molecule of water.
The oxygen in a water molecule can link up with iron atoms in a car fender. The oxygen and iron react to form rust. Oxygen in the air reacting with carbon atoms in wood can make carbon dioxide. Carbon dioxide is a gas that plants need to live.
FAST AND SLOW REACTIONS
Some chemical reactions are very slow. Rust can take years to form.
Other chemical reactions happen very fast. The flame you see when wood or paper burns is actually a fast chemical reaction. An explosion is an extremely fast chemical reaction.
Now link your fingers together. Curl them around one another and pull. It’s hard to pull your hands apart. Linking your fingers is like a chemical reaction.
MIXING CHEMICALS
A chemical reaction can happen when you mix two or more chemical elements together. A chemical element is made of only one kind of atom. There are more than 100 different kinds of atoms. Atoms are much too small to see.
Atoms that make up chemical elements link together in chemical reactions. A chemical reaction makes a new kind of chemical substance. The new substance is different from the chemicals that made it. Chemists use chemical reactions to make all kinds of substances. They have made millions of new substances, including many kinds of plastics and medicines.
ATOMS AND MOLECULES
Atoms link up to make molecules. A molecule has two or more atoms. Chemical reactions make new molecules.
Oxygen atoms take part in many chemical reactions. Oxygen and hydrogen atoms link up to make a molecule of water.
The oxygen in a water molecule can link up with iron atoms in a car fender. The oxygen and iron react to form rust. Oxygen in the air reacting with carbon atoms in wood can make carbon dioxide. Carbon dioxide is a gas that plants need to live.
FAST AND SLOW REACTIONS
Some chemical reactions are very slow. Rust can take years to form.
Other chemical reactions happen very fast. The flame you see when wood or paper burns is actually a fast chemical reaction. An explosion is an extremely fast chemical reaction.
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