Writing and balancing chemical equations from words

The idea for the posters I'm posting below came from her beautiful classroom displays which she has posted pictures of here. She even links to files so you can recreate them yourself!

Writing and balancing chemical equations from words

Hydrogen sulfide, H2S Ammonia, NH3 How did you know which of the substances in the table were compounds and not elements? You probably looked to see which ones were made up of more than just one kind of atom.

A compound is a material that consists of atoms of two or more different elements. The elements are not just physically mixed, but chemically bonded together at the atomic level. Water H2Ocarbon dioxide CO2 and salt or sodium chloride NaCl are examples of compounds, while oxygen gas O2hydrogen gas H2 and nitrogen gas N2 are examples of elements.

The compound with the formula H2O2 also consists of hydrogen atoms and oxygen atoms. The formula tells us that one molecule of this substance is made up of two atoms of hydrogen and two atoms of oxygen. Is H2O2 the same as water?

Interactive Chemistry Worksheets for Students

What do you think? Do not confuse H2O2 with H2O! H2O2 is a compound called hydrogen peroxide. The following properties of hydrogen peroxide may convince you that it is not the same as water: Concentrated hydrogen peroxide is so reactive that it is used as a component in rocket fuel!

Hydrogen peroxide is extremely corrosive. We can drink water, but hydrogen peroxide is very hazardous and harmful.

Corrosive substances are substances that cause damage to metal or other materials through a chemical process. Think of rainwater causing rust that eats away at metal. If this doesn't convince you, let us compare what the hydrogen peroxide molecule looks like next to water: Even though they are made up of exactly the same elements, the two compounds are very different and should never be confused with one another.


The purpose of the comparison of hydrogen peroxide and water above was to show you that the atoms in a given compound are always combined in a fixed ratio.

In all water molecules in the universe, there will always be one O atom and two H atoms bonded together. This was the fifth of Dalton's postulates: Atoms chemically combine in fixed ratios to form compounds.

How do atoms 'combine'? What makes them stick together to form molecules? Chemical bonds Look at the photo with the different arrangements of metal balls.

These balls are magnetic and this allows you to make different patterns by sticking them together. What makes magnets stick together? Learners may say that magnets stick together because they attract each other.

Point out to them that magnets will indeed attract each other if they are lined up correctly. Magnets can also repel each other if they are lined up differently.

Learners will look more at magnetic forces in Gr. These balls are magnetic. When atoms combine, they do so because they also experience an attractive force. The force is slightly more complex than the force between magnets, but it works in the same way: The force holds atoms together as if they are stuck together with glue.

The forces that hold atoms together are called chemical bonds. In the water molecule, chemical bonds between O and the two H atoms hold the whole molecule together. How many chemical bonds in each water molecule? Look at the diagram below if you are not sure: If you want to stretch the learners beyond curriculum requirements at this point, you could give a brief explanation of electron sharing.

writing and balancing chemical equations from words

The details of this will only be explored in Gr. These strong chemical bonds, called covalent bonds, are formed when atoms share their electrons.Writing and balancing chemical equations from words: Types of reaction worksheet: Balancing equations from words worksheet answers: Auburn School District.

Subscribe to our E-Newsletter. Our Mission: In a culture of equity and excellence we engage, educate, and empower each student for success beyond graduation. • Write and balance equations originally stated in words.

At the completion of this episode's lesson(s), you should be able to: • Use the law of conservation of mass and provide standard rules for writing and balancing equations. As a member, you'll also get unlimited access to over 75, lessons in math, English, science, history, and more. Plus, get practice tests, quizzes, and personalized coaching to help you succeed.

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PRESENTATION NATIONAL HIGH SCHOOL, BENIN CITY. SCHEME OF WORK FOR PHE. JSS 1. 1ST TERM. Definition, nature, scope and objectives of physical education. Chapter overview. 2 weeks. This chapter introduces the fundamental building blocks of matter and some of the important classification schemes scientists use to communicate about matter.

Natural Sciences Grade 8