Vocab/ Concepts
What vocabulary term refers to unique characteristics of a substance?
Properties
What is the name of the small number in the chemical equation and what does it tell you.
1. The subscript
2. The number of specific atoms.
What is a physical change?
a change that doesn't change properties or creates a new substance. Can be changed back easily.
What is a chemical change?
A chemical change is a change that rearranges atoms and creates new substances.
What color is granny smith apple?
Green
What term refers to a single atom or molecule that is the same through and through.
Pure Substance
What does the larger number in front of the molecule tell us in a chemical equation and what is it called?
1. It tells us the number of atoms in the molecule and
2. it's called a coefficient.
List 3 properties of a physical change
1. Melting Point
2. Freezing Point
3. Boiling point
4. Density
5. Solubility
In baking biscuits and other quick breads, the baking powder reacts to release carbon dioxide bubbles. The carbon dioxide bubbles cause the dough to rise. What is evidence that a chemical change happened?
1. The baking powder reacting to release carbon dioxide.
2. The bubbles caused the dough to rise.
What is the difference between an exothermic reaction and an endothermic reaction?
Exothermic reactions the heat leaves while endothermic reactions heat is kept and absorbed.
What are the two ways scientist make use of properties of matter?
To classify and identify
Balance this equation:
____ Cu2O +____ C ---> _____ Cu + _____ CO2
_2__ Cu2O + ____ C ----> _4_ Cu + ____ CO2
Sam and Rebecca say cutting a paper into 12 pieces is not a physical change because the paper is in small pieces. Explain why they are correct or incorrect.
They are incorrect because size is not a property and the paper did not change.
What is the difference between single replacement and double replacement reactions.
Only one atom is swapped out in single replacement and two are swapped in double replacement.
14:00
A scientist has two containers. Inside each container is a blue liquid. Liquids are substances. What are two things that scientists can do to help find out whether these two liquids are both the same substance?
1. Check the density of the liquids
2. another property like flammability or freezing point.
____ Al + ____Fe2N2 ----> ____ AlN + ____ Fe
__2_ Al + ____Fe3N2 ---> _2_ AlN + __3_ Fe
Janet explained the dissolving chocolate into milk is physical change because it she can take the milk back out by using evaporation. Explain why she is right or wrong. Include the property.
She is right. Dissolving chocolate into milk is solubility. Solubility is a physical property.
What are the 5 signs that a chemical change has happened? *All 5 for the points*
1. Bubbles
2. Temperature increase or decrease (Exothermic/Endothermic)
3. Light formation
4. Creation of a precipitate (New substance formed)
5. Color change.
What is the difference between a closed and open system? Give an example for both.
A closed system is a system where matter cannot escape (Aquarium, closed bottle, Terrarium) and an open system is a system where matter can escape (our classroom, an open bottle, a fire)
Mary and Martha wanted to start a soap-making business. They must first figure out how to make soap. They read an article about how colonists made soap using animal fat and hydroxide. After mixing the two substances together Martha asked Mary how can it be determined if the soap that we made is a new substance. How could you help?
Compare the properties of both soaps.
____ NaBr + ____ CaF2 ----> ____ NaF + ____ CaBr2
2 NaBr + 1 CaF2 2 NaF + 1 CaBr2
Why is water condensing on a bottle considered a physical change?
Because during physical change the state of a substance changes. Since during condensation the water vapors (gas) are converted to water (liquid)
Explain why electrolysis produces a new substance. Include the type of reaction.
The reactant is water and it yields hydrogen and oxygen gases as the products. This type of reaction is decomposition reaction because it is breaking the water molecule down into two substances.
What holiday just passed?
Veteran's day- November 10th