Chemical Changes
What is the difference between a chemical and physical property?
A Physical Property is one that can be observed without a reaction.
A chemical property must have a reaction in order to be viewed.
In a physical change, I should see the ___ or the ____ change.
State, or shape
Balance this equation... N2 + 3H2 > NH3
N2 + 3H2 > 2NH3
The molecules/chemicals that go into a chemical reaction are called...
reactants (because they react)
What is a precipitate?
A solid that is formed because of a chemical reaction
What is always created in a chemical reaction?
A new substance
True/ False:
Volume of the substance will change as it changes physically
True: Melting/Evaporating
Balance this equation... Reactants: 2KClO3 > KCl + O2
2KClO3 > 2KCl + 3O2
If it is a CLOSED SYSTEM, how many grams of product should we end up with?
Na+ Cl -> NaCl
Na= 100 grams
Cl= 100 grams
200 grams of product
True/False: It is possible to speed up chemical reactions
True- catalyst, mixing or heat
What are three examples of chemical properties?
Flammable, toxicity, reactivity, radioactivity, pH
True/False:
Color of the substance will change as it changes Physically
False
Balance this equation... 2NaCl + F2 > NaF + Cl2
2NaCl + F2 > 2NaF + Cl2
If it is an OPEN SYSTEM, how many grams of product would we end up with?
2Cu₂O + C --> 4Cu + CO₂
REACTANTS: 100 grams
PRODUCTS: ???
Less than 100 grams
What is dry ice?
Solid CO2
What is one way we can observe that a chemical change has occured?
-Light produced
-Sound produced
-Spontaneous heat/cold
-Bubbling/Fizzing (not from boiling)
-Formation of a precipitate
What are 4 examples of physical properties?
Color, shape, density, malleability, ductility, mass, weight, volume, phase, freezing point, boiling point, melting point, solubility, specific heat,
Balance this equation... CH4 + O2 ---> CO2 + H2O
CH4 +2O2 > CO2 + 2H2O
If I start with 20 grams of NaCl, and I end up with 15 grams of Sodium, how many grams of Chlorine will I have?
NaCl --> Na + Cl
5
What is vinegar's acid name? (Spelling needed!)
Acetic Acid
What is the definition of a closed system and an open system?
Closed system- all matter is maintained, none can escape
Open system- matter can escape into the enviroment
Jimmy does an experiment with salt and water. He dissolves 20 grams of salt into 50 grams of warm water. He notices that the water seemed a little cloudy after, but there were no other changes. Is this a physical or a chemical change?
Physical change- solubility. Nothing new was made.
Balance this equation... HCl + CaCO3 ---> CaCl2 + H2O + CO2
2HCl + CaCO3 -----> CaCl2 + H2O + CO2
Some of the water escaped through evaporation into the atomosphere
What is Vitamin C's acid name? (spelling needed)
Ascorbic Acid