Answer: Although the best-known cause of a mass extinction is the asteroid impact that killed off the non-avian dinosaurs, in fact, volcanic activity seems to have wreaked much more havoc on Earth's biota. Volcanic activity is implicated in at least four mass extinctions, while an asteroid is a suspect in just one. Examples, of mass extinctions are Permian extinction of marine species, and Cretaceous extinction of various species, including dinosaurs.
Answer:
Here are a few more examples:
Smoke and fog (Smog)
Dirt and water (Mud)
Sand, water and gravel (Cement)
Water and salt (Sea water)
Potassium nitrate, sulfur, and carbon (Gunpowder)
Oxygen and water (Sea foam)
Petroleum, hydrocarbons, and fuel additives (Gasoline)
Heterogeneous mixtures possess different properties and compositions in various parts i.e. the properties are not uniform throughout the mixture.
Examples of Heterogeneous mixtures – air, oil, and water, etc.
Examples of Homogeneous mixtures – alloys, salt, and water, alcohol in water, etc.
Explanation:
The coefficient in a chemical formula represents the amount of each chemical present. The amount of a substance is measured in moles.
Answer: 25.8 g of 
will be produced from the decomposition of 73.4 g of 
Explanation:
To calculate the moles :
The balanced chemical reaction is:
According to stoichiometry :
2 moles of produce = 3 moles of
Thus 0.242 moles of will produce= 
of
Mass of = 
Thus 25.8 g of will be produced from the decomposition of 73.4 g of
2.13 miles
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