Physical & Chemical Changes
What is the difference between a chemical and physical change?
A physical change does not change the composition, while a chemical change does
How many CARBON are in Na(CO3)2?
2
CH4 + 2O2 → CO2 + 2H2O
What is the coefficient for water?
2
Synthetic materials are made from ___________________
Natural Resources
Endothermic reactions _________ (absorb/release) energy and feel ________ (hot/cold) to touch.
Absorb;cold
Give an example of chemical change.
Rusting, Reacting, forming bubbles, etc.
How many Phosphorus are in (NH4)3PO4?
1
What side of an equation would you find the products?
right
What are the three types of synthetic materials?
Animal, Plant, Petroleum
Chemical reactions that absorb energy are called __________________. Chemical reactions that release energy are called __________________
Endothermic, Exothermic
Give an example of a physical property.
mass, density, 5 senses, weight, etc.
2P2O3
How many of each element is there?
P-4 O-6
Which is balanced?
a. C3H8 + 5O2 --> 3CO2 + 4H2O
b. 2C3H8 + 5O2 --> 3CO2 + 8H2O
a. C3H8 + 5O2 --> 3CO2 + 4H2O
Minerals Plastic Crops Cake Basketball Cotton Flag Fossil Fuels
Which of these are natural?
Cotton, Minerals, Fossil Fuels, Crops
CaO + H2O → Ca(OH)2 + Heat
What kind of reaction is this?
Exothermic
Which action will result in a product with new properties?
Shredding a worksheet
Baking a cake
Breaking a glass bowl
Cutting wood.
Baking a cake
(NH4)3PO4
How many of each element are there?
N-3
H-12
P-1
O-4
How do balanced equations follow the Law of Conservation of Mass?
In a balanced equation, there are the same number of each atom on both sides
True or false.
Animals are a renewable resource.
True
A beaker of water in sunlight becomes warm. Has a chemical reaction occurred? Explain.
various answers
Why is vinegar freezing a physical change, and not a chemical change?
The vinegar freezing is not changing the molecules of the vinegar, it is just changing phases, so it is a physical change.
What does the coefficient 2 in the following formula mean?
2H20
there are 2 water molecules formed together
Balance this equation.
AlBr3 + K2SO4 --> KBr + Al2(SO4)3
2AlBr3 + 3K2SO4 --> 6KBr + Al2(SO4)3
Explain how a natural resource that was once renewable can become non-renewable. Give an example.
various responses
Thinking of the Law of Conservation of Mass, if the reactants are 15 grams, how much will the products be?
the same, because matter cannot be created or destroyed.