Vocabulary
A process where two or more substances mix to form a new substance with different properties
What is a chemical reaction?
Which state of matter has particles that spread out to fill all the space available?
Gas
When baking soda is added to an acidic liquid, what is one thing you might observe?
Bubbling / Fizzing
In a fair test, should you change one variable or many variables at the same time?
One variable
What is one sign that a chemical reaction may have happened?
Gas/bubbles, temperature change, color change, new substances being created (think slime being made out of glue and borax)
Something you can observe about an object or material
What is a property?
Compared with particles in a liquid, how are particles in a gas arranged?
They are much farther apart and can move throughout the container.
You test orange juice and water with baking soda. Orange juice fizzes but water does not. Which liquid is more likely acidic?
Orange juice.
Two students want to test whether the amount of baking soda changes a reaction. What should they keep the same?
The amount/type of other substances and other testing conditions.
Baking soda and vinegar are mixed and bubbles immediately form. What do the bubbles provide evidence of?
A gas was produced during a chemical reaction.
Anything that takes up space and has weight; can be in different forms such as solid, liquid, or gas
What is matter?
Baking soda and vinegar react inside a sealed plastic bag and the bag expands. What are the invisible particles doing?
Gas particles are spreading out and pushing against the bag.
Three liquids are tested with equal amounts of baking soda. Liquid A has a lot of bubbles, liquid B has no bubbles, and liquid C has some bubbles. Which liquids show evidence of being acidic?
A and C
A student mixes vinegar with one spoon of baking soda and then vinegar with three spoons of cornstarch. Is this a fair test of which solid reacts with more vinegar? Why or why not?
No; different amounts of the solids were used.
A student mixes two clear liquids. The mixture becomes cloudy and a solid appears. What evidence suggests a chemical reaction occurred?
A new solid substance formed.
A combination of two or more things
What is a mixture?
A ballon placed over a bottle gets larger after two substances react inside the bottle. Describe how the particles inside the balloon should be shown.
Many gas particles spread far apart throughout the balloon.
A mystery liquid fizzes strongly with baking soda. Can you conclude exactly what the liquid is? Explain.
No. You can infer it may be acidic, but many different acids can react with baking soda.
You want to find out whether baking soda or cornstarch react more with vinegar. Describe a fair test.
Use equal amounts of each solid in separate containers, at equal amounts of the same vinegar, keep all other conditions the same, and compare the reactions.
After a reaction in an open container, the materials left behind weigh less than they did before. Does this mean matter disappeared?
No. A gas may have formed and escaped into the air.
A special kind of mixture where two substances mix together and it looks like one of them disappears
What is a solution?
A student says, "The bag gets bigger because new matter appears when the baking soda and vinegar react." Use a particle model to correct the student.
Matter does not appear from nowhere; particles from the starting substance rearrange into new substances, including gas particles that spread out and expand the bag.
Four mystery liquids are tested with baking soda. A and B fizz, while C and D do not. What can you conclude, and what can you not conclude from this test alone?
A and B show evidence of acidic properties; You cannot identify exactly what each liquid is from the test alone.
Mix 1 spoonful of Powder A into 1 cup of vinegar. Then, mix 1 spoonful of Powder B into 1 cup of vinegar. What kind of test is this?
A fair test
Two substances are mixed in a sealed bag. The bag gets colder, bubbles form, and the bag expands. Give 2 pieces of evidence that a chemical reaction occurred and explain why the bag expands.
Temperature change and gas bubbles are evidence; newly formed gas particles spread throughout the bag and push outward.