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Solutions, Acids, Bases
Physical vs. Chemical Changes
Law of Conservation of Mass
Energy in Reactions
Types of Chemical Reactions
100
Which is the solvent in this example: A solution consists of 45g H2O and 50g H2O2
H2O2 is the solvent (there is more of it)
100
Steam rising from water is a chemical or physical change?
Physical change
100
What is the law of conservation of mass?
Mass is neither created nor destroyed in chemical reactions, it only changes form. The amount of reactants equals the amount of products.
100
What are the two types of reactions based on energy?
Endothermic and Exothermic
100
Elephant Toothpaste is an example of what kind of atom movement reaction?
Decomposition
200
What is the formula for calculating concentration?
Concentration = (mass of solute) / (mass of total solution) x 100%
200
This type of change only affects the form or state of the molecules, but does not create any new molecules.
Physical change
200
Who discovered the Law of Conservation of Mass?
Antoine Lavoisier
200
If you see energy being produced (on the right side of an equation), what type of chemical reaction is it?
Exothermic
200
Sodium Sulfate and Barium Chloride was an example of what kind of atom movement reaction?
Double replacement
300
What is the solvent that acids and bases dissolve into?
H2O
300
List the pieces of evidence that tell you a chemical change has happened.
Color change Odor change Formation of a gas (bubbles) Formation of a solid (precipitate) Energy change (heat, light)
300
Rewrite the Law of Conservation of Mass without using the words "matter," "mass," "weight," "stuff," or "things."
The number and type of atoms are the same at the start and end of a chemical reaction.
300
Which type of reactions require activation energy?
Endothermic AND Exothermic. However, exothermic reactions may already have that activation energy within the reactants, while endothermic may require an external source of activation energy.
300
Iron and Copper sulfate was an example of what kind of atom movement reaction?
Single replacement
400
What is the ion produced by acids, and what is the ion produced by bases? Tell me the name and formula, and indicate which is the acid's and which is the base's.
Acid = hydronium = H3O+ Base = hydroxide = OH-
400
You have ice, liquid water, an alka seltzer antacid tablet, and some beakers available to you. Use this equipment to show a physical change and a chemical change
Answers will vary. One example of a physical change would be to place the ice in a beaker and melt it over time. One example of a chemical change would be to dissolve the antacid tablet in a beaker of water.
400
Balance the following equation: ___Al(OH)3 + ___H2CO3 → ___Al2(CO3)3 + ___H2O
2 Al(OH)3 + 3 H2CO3 → 1 Al2(CO3)3 + 6 H2O
400
In order to decompose 100g H2O2 into 100g of H2O and 50g O2, you need about 100joules of activation energy at room temperature. If you have 50joules of activation energy, how much H2O and O2 can you get by decomposing 100g of H2O2?
NONE! If you don't have the total activation energy, the reaction will NEVER start.
400
3H2 + N2 --> 2NH3 is an example of what kind of atom movement reaction?
Addition
500
What are the products of this base reaction? NH3 + H2O -> _____ + _____
NH3 + H2O -> NH4+ + OH-
500
How did you know the elephant toothpaste reaction was a chemical change?
Formation of a gas, change in energy (heat)
500
Balance the following equation: ___Fe + ___FeCl3 → ___FeCl2
1 Fe + 2 FeCl3 → 3 FeCl2
500
Catalase in an enzyme in your body that makes chemical reactions happen more often than they usually would. Catalase is well named because it is a ____________. Where would you write catalase in a chemical equation?
Catalase is a catalyst. You write it above the arrow.
500
Ca(OH)2 + 2HNO3 --> Ca(NO3)2 + 2H2O is an example of what kind of atom movement reaction?
Double replacement