Vocab
Multiple Choice
Short Response
Labs
100
To prevent the loss of something
Conserve
100
In a chemical reaction known as decomposition, carbonic acid breaks down into water, and what other compound?
A.
B.
C.
D.
B.
100
What does the Law of Conservation of Mass say about matter?
Matter cannot be created or destroyed and therefore the mass will not change after a reaction.
100
Was the candle lab an open or closed system? Why?
It is an open system because the gas from the flame is able to escape
200
The smallest part of all matter
Atom
200
A student is using the following key to model the chemical equation provided.
Chemical Equation: MgCl2 + 2NaF -> MgF2 + 2NaCl
The reactants are on the left and the products are on the right. How many blue beads will the student need to model each side of the equation?
A. 1 for the products and 1 for the reactants
B. 2 for the products and 2 for the reactants
C. 2 for the products and 1 for the reactants
D. 1 for the products and 2 for the reactants
B. 2 for the products and 2 for the reactants
200
Hydrogen peroxide (H2O2 ) is unstable under certain conditions and decomposes as follows:
2H2O2 → 2H2O +O2
40 g ?
What will be the result when starting with 40 grams of hydrogen peroxide?
40g of total products because of the Law of Conservation of Mass
200
What did all the labs throughout this unit have in common?
They were all related to the Law of Conservation of Mass because they showed how an open system cannot contain matter and will change the mass, but a closed container will trap all matter and the mass will stay the same.
300
The amount of matter in an object
Mass
300
Students want to gather evidence for the claim that the number of atoms present before a chemical reaction is equal to the number of atoms present after the chemical reaction. They decide to react vinegar and baking soda in a sealed plastic bag. Which of the following would provide the evidence the students need?
A. The mass of the plastic bag, baking soda, and vinegar before the reaction was equal to the mass after the reaction.
B. Bubbles were produced during the reaction, which meant that a gas was being produced.
C. The plastic bag did not change in any way, indicating that it was not involved in the reaction.
D. The mass of baking soda was exactly equal to the mass of the vinegar used to create the chemical reaction.
A. The mass of the plastic bag, baking soda, and vinegar before the reaction was equal to the mass after the reaction.
300
Why are ratios important? Where do you think ratios are used outside of school?
Ratios allow companies to increase efficiency and determine the proper amounts of the reactants. Used in baking/cooking, making a certain paint color, engineering, construction, etc.
300
Which system lost more mass? The alcohol or candle? Why?
The alcohol because the flame is larger which is burning faster and turning the alcohol into a gas.
400
When atoms of substances rearrange themselves into a new configuration
Chemical reaction
400
Which of the following atomic models of chemical reactions correctly demonstrates the Law of Conservation of Matter?
A.
B.
C.
D.
B.
400
Describe an experiment that can be done to prove the law of conservation of mass.
Vinegar baking soda with balloon on top. Any closed system in which a chemical reaction occurs.
400
Which lab would NOT give evidence for the Law of Conservation of Mass? Why?
Any open system which does not contain the products because the mass changes after the reaction takes place. ex: flame lab or open baking soda and vinegar flask
500
The total number of atoms of each element is not changed during a chemical reaction
Law of Conservation of Mass
500
Which of the following is true regarding the atoms involved in a chemical reaction?
A. The same number of each type of atom will always be present before and after a chemical reaction takes place.
B. Some of the atoms present before the reaction will always be lost during a chemical reaction.
C. Some of the atoms will always be changed into a different type of atom by a chemical reaction.
D. During a chemical reaction, atoms will always be combined into much larger molecules.
A. The same number of each type of atom will always be present before and after a chemical reaction takes place.
500
What is an example in nature where a chemical reaction occurs in an open system?
Examples include cooking in an open pan, camp fire, rotting roadkill, etc.
500
Describe how ratios helped you throughout the baking soda and vinegar lab?
Once you figure out the appropriate ratio for the 10mL graduated cylinder, you can easily find the proper amounts for the 50mL and 100mL by scaling them up.