Chemical Reactions! , livre ebook

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CONTENTS
Timeline
Periodic Table of Elements
Introduction Chemistry Matters!
Chapter 1 Mixtures: Be a Detective
Chapter 2 Abracadabra: Chemical Reactions
Chapter 3 Water, Acids, and Bases
Chapter 4 It s a Gas!
Chapter 5 Manmade Compounds
Glossary * Metric Conversions Resources * Essential Questions * Index

Interested in primary sources? Look for this icon. Use a smartphone or tablet app to scan the QR code and explore more! Photos are also primary sources because a photograph takes a picture at the moment something happens.

You can find a list of URLs on the Resources page. If the QR code doesn t work, try searching the internet with the Keyword Prompts to find other helpful sources.
EXPLORE CHEMICAL REACTIONS
TIMELINE

300 BCE: Ancient Greek philosopher Aristotle declares the existence of only four elements: fire, air, water, and earth. He says, mistakenly, that all matter is made up of these four elements.

430 BCE: Democritus, an ancient Greek philosopher, proclaims the atom to be the simplest unit of matter.

1649: German pharmacist Hennig Brand discovers the element phosphorous. Elements such as gold, silver, tin, copper, lead, and mercury had been known for a long time, but this was the first scientific discovery of an element.

1789: Chemist Antoine Lavoisier shows that the mass of products in a reaction is equal to the mass of the reactants. In other words, no mass is lost in a chemical reaction. This became known as the law of conservation of mass. It is one of the most important and basic laws of modern chemistry and physics.

1803: Chemist John Dalton publishes his atomic theory, which states that all matter is composed of atoms, which are small and indivisible. The Greeks had many of these ideas and Dalton built on them.

1869: Russian chemist Dmitri Mendeleev creates the first periodic table by grouping together elements that act alike. The gaps in his table are where undiscovered elements will fit in later.

1890s-1900s: Marie and Pierre Curie discover radioactive materials and two new elements. They win a Nobel Prize in 1903 and Marie wins a second one in 1911. She is the first woman to win a Nobel Prize and the first person to win two Nobel Prizes!

1932: The first nuclear fusion reaction is performed in a laboratory. This process involves smashing together two or more smaller elements to form a heavier element. Every star in the universe, including the sun, uses nuclear fusion to produce energy.

1938: German chemists Otto Hahn and Lise Meitner discover nuclear fission when large uranium atoms are split apart. Today, nuclear fission is used to generate 10 percent of the world s bodyelectricity.

2017: Three scientists develop a method to see the three-dimensional structure of cells on an atomic level, paving the way for new medicines and therapies.

2020: Emmanuelle Charpentier and Jennifer A. Doudna win a Nobel Prize in chemistry for the development of a method of gene editing that might help treat certain diseases.
PERIODIC TABLE OF ELEMENTS
INTRODUCTION
CHEMISTRY MATTERS!
You might think chemistry happens only in a laboratory with people wearing white coats. Not true! Chemistry is all around us! We come across chemical reactions every day.
Did you eat toast this morning? That toast was a result of a chemical reaction. Did you wash your hands before you ate your toast? Soap cleans because of a chemical reaction, too! There s even chemistry happening inside your own body as you break down the food you eat into nutrients .
Chemistry is the science of change and it always happens for a reason. People have been trying to discover those reasons for centuries.
INVESTIGATE!

Where can you see chemistry happening right now?
WORDS TO KNOW

chemistry: the science of how atoms and molecules combine to form substances and how those substances interact, combine, and change.
atom: the smallest particle of an element. Atoms are the tiny building blocks that make up everything in the universe.
molecule: a group of atoms bound together to form a new substance. An example is water (H 2 O), which is two hydrogen atoms and one oxygen atom.
chemical reaction: the combination of two or more substances that results in a completely new chemical substance. This can also mean the chemical breakdown of one substance into its parts.
nutrients: substances in food and soil that living things need to live and grow.
substance: the material that something is made of. alchemist: a person who practiced an early form of chemistry with the goal of turning ordinary metals into gold.
theory: a set of ideas based on observation and data to explain something that has happened.
CHEMISTRY HISTORY
Scientists who specialize in chemistry are called chemists. The first chemists date back to ancient times, but they weren t called chemists. They weren t even scientists! They were just people who wondered, What happens if I put potatoes into a fire? or Why is a cooked egg different from a raw egg?
These people were simply curious. They wanted to know what might happen if they mixed different substances to make something new.
Alchemists were some of the first thinkers who experimented with chemical reactions. Their goal? To change regular metal into gold! No one ever succeeded at this, but these people learned more and more about the science of chemistry.
As people became better at recording their observations and measurements, scientists did experiments to find out more about the world we live in. As the tools and techniques that chemists used improved, scientists could develop even more accurate theories about how our world works.
WORDS TO KNOW

matter: anything that has weight and takes up space. Almost everything is made of matter!
gas: a substance in which atoms and molecules are spread far apart.
element: a pure substance that contains only one kind of atom.
Today, chemists still study matter . They still ask questions about how matter is put together, how it changes, and why it sometimes doesn t change at all. They ask what s happening when matter fizzes, explodes, or changes color! Chemistry is called a central science because matter is all around us.
MATTER MATTERS!
Everything you see right now is made of matter. A fern, a ham sandwich, and the moon. Your dog, the milk you drank for lunch, and the carton it came in are also made of matter. Even the air you re breathing is made of matter. Matter is anything that takes up space and has mass. We are made of matter, but what is matter made of?

HAVE YOU EVER COOKED AN EGG? THAT S A CHEMICAL REACTION!

DID YOU KNOW?
Hydrogen, a gas , is the most common element . Hydrogen forms part of every living thing on our planet!
WORDS TO KNOW

property: a characteristic of something. The way something looks or behaves.
particle: a tiny piece of matter.
Matter is made of atoms. Atoms are the building blocks for all matter and are too tiny to see. In fact, millions of atoms would fit in the period at the end of this sentence.
Have you ever played with a balloon filled with helium? Do you know anyone who wears gold jewelry? Both helium and gold are special kinds of matter. They are elements! An element is a pure substance made of just one kind of atom. All atoms in gold are gold atoms. All atoms in helium are helium atoms. Elements combine together in different ways to make up all the matter in the world.

Different elements behave in different ways. Gold doesn t make a balloon float and you can t wear helium around your neck! Instead, all the elements have different properties .

ROBERT BOYLE SETS THE RECORD STRAIGHT
People used to think that there were only four elements: fire, air, water, and earth. They thought this was true for more than 2,000 years. In 1661, a chemist named Robert Boyle (1627-1691) challenged this idea. He performed many different experiments that showed there were more than just the four different elements. He also helped show that matter was made up of tiny particles that behave differently at different times. He proved that gases are small particles surrounded by space.
WORDS TO KNOW

periodic table: a chart that shows the chemical elements arranged according to their properties.
symbol: an image or character that stands for something else.
All 118 elements are important in the study of chemical reactions. How do chemists keep track of all these elements?
THE PERIODIC TABLE
The periodic table is a chart that lists all the known elements. Some of these elements are found only in laboratories and are made by scientists. Ninety-eight of them are found in nature.
On the periodic table, each element has a number, a name, and a symbol . Each element has its own box with the element s name, its symbol, and how heavy it is.

DID YOU KNOW?
Scientists are still discovering new elements! In 2016, four new elements were added to the periodic table. You can learn more about elements in this interactive chart.

INTERACTIVE PERIODIC TABLE KIDS
As you can see from the chart, H is for hydrogen and O is for oxygen.

WORDS TO KNOW

solid: one of the states of matter where the particles are bound tightly and do not move much. This book is a solid.
But ... what about iron? The symb