chemical reactions 3-1

Focus Question: What happens when you combine

different chemicals?

Fizz Quiz

Investigation3-1

Chemical Introduction

• What do you know about these substances?– Citric Acid– Baking Soda– Calcium Chloride

• Safety First!– Don’t taste– Wear goggles

What do you remember about Solutions?

• How can you make a solution?

• How do you know if a mixture is a solution?

• What does solubility refer to?*

• Do you think these three chemicals will make solutions with water?

• How can you find out?

Make Solutions• Groups 1, 3, 5, & 7 will test Baking

Soda

• Groups 2, 4, 6, & 8 will test Calcium Chloride

• Testing Procedure:– Get one spoon of assigned chemical in cup– Add 50 ml of water to substance and stir

Solution Results• Baking soda and water make a solution

– Needed to add 25 ml of water– Not as soluble as citric acid, kosher salt

• Calcium Chloride and water make a solution– Property of Calcium Chloride

• as it dissolves, energy is released in the form of heat

Two-Chemical Solutions• Know that citric acid, calcium chloride,

and baking soda all form solutions when mixed with water.

• Do you think mixtures of these substances will form solutions when they are mixed with water?– If you mix baking soda and calcium

chloride with water, will a solution form?

Fizz-Quiz Place Mat• Place Mat will help organize your

investigations.

• Label 3 cups: 1, 2, and 3

• Different pair of substances in each cup– Cup 1: Calcium Chloride and Baking Soda– Cup 2: Calcium Chloride and Citric Acid– Cup 3: Baking Soda and Citric Acid

• Once cups are labeled, set them on the corresponding circle on Fizz-Quiz place mat

Fizz-Quiz Observation Sheet• Record your observation using both

drawings and written descriptions of what the group observes.

• Investigate Cup 1 - draw and write what you observe - use multisensory observations

• Investigate Cup 2 - observe as above

• Investigate Cup 3 - observe as above

Observations• Did the mixture of substances result in

solutions when they were mixed with water?

• Set Cup 1 on the window sill for later

• Rinse and replace cups and stir sticks in bins.

• Clean up

Results• What do you think caused the fizzing in

cups 1 and 3?• Fizzing in a liquid is caused by gas

escaping and coming to the surface.• When calcium chloride and baking soda

are mixed with water, the gas Carbon Dioxide forms.

• When citric acid and baking soda are mixed, Carbon Dioxide forms.

• Carbon Dioxide is the same gas that make the bubbles in soda water.

• What do you think the white stuff is in Cup 1?

• The white material is a new substance that formed when calcium chloride and baking soda mixed with water.

• The new substance, Calcium Carbonate (chalk), is not soluble in water.

• Settles to the bottom of the cup.

• When a solid substance forms and settles out of a liquid, it is called a Precipitate.

Changes• Production of gas and formation of

precipitate are both Changes.• When two or more substances are

mixed together and a change occurs:– Change is Evidence that a Chemical

Reaction has taken place– Reaction results in new substances with

properties that are different from the properties of the original substances

– Starting substances called Reactants.– New substances that form called

Products.

Reactions• Did a chemical reaction take place in

cup 1?– How do you know?

• Cup 2?– How do you know?

• Cup 3?– How do you know?

• What were the reactants in cup 1?

• What were the products in cup 1?

Carbon Dioxide• Carbon dioxide is matter.

– Made of particles– What do carbon dioxide gas particles look

like?

Matter• Everything in the world is made of

atoms.

• Small particles of matter

• 90 different kinds of naturally occurring atoms on Earth

• Circles represent atoms– C = Carbon – O = Oxygen

Atoms and Molecules• Carbon is a substance

– Made of Carbon atoms only– Carbon atom is the basic particle of the

substance carbon

• Oxygen is a different substance– Made of oxygen atoms only– Oxygen atom is the basic particle of the

substance oxygen

Molecules• Atoms can combine with one another.• When two or more atoms combine, they

form Molecules.• Basic particle of carbon dioxide is a

molecule made of one carbon atom and two oxygen atoms.

• Vocabulary next:

Vocabulary

• Carbon dioxide (CO2)

– one of the gases in air. Carbon dioxide can be a product of a chemical reaction.

• Chemical reaction

– takes place when two or more substances are mixed together and a change occurs.

• Change

- the process of becoming something different.

• Energy

– can take a number of forms and can change from one form to another.

– Heat is one form of energy and can be released during chemical reactions and when substances dissolve.

• Evidence– used by scientists to support their ideas and

conclusions. – Evidence is based on observation.

• Reactants – the starting substances in a chemical

reaction.

• Products – the new substances that form in a

chemical reaction.

6CO2 + 6H2OC6H12O6 + 6O2

Reactants Products

• Precipitate - a solid material that forms as a product of a reaction.

• Atoms - the smallest particles of matter. Everything is made of atoms.

• Molecules - atoms combined together. The basic particles of substances.

Content

• What happens when a solution is made with water and two different solutes?

• Sometimes when two (or more) substances are mixed, a reaction occurs; reactants form new products.

• How do you know when a chemical reaction has occurred?

• Changes, such as heat, gas formation, and precipitate formations, are evidence of a chemical reaction.

Content

• What are the basic particles of matter?

• Atoms are the smallest particles of matter. Atoms can combine to make molecules, which are the basic particles of most substances.

• Your questions?