chemical reactions 3

The changes that are visible during a chemical reaction are signs that what is being rearranged in the reactants?

• electrons

• atoms

• products

• nuclei

What type of reaction has the reactant broken down into other substances?

• synthesis

• decomposition

• combustion

• single replacement

What is the right part of a chemical equation called?

2H₂ + O₂ ---> 2H₂O

• Reactants

• Yields

• Products

• Chemical Equation

What is the left part of a chemical equation called?

2H₂ + O₂ ---> 2H₂O

• Reactants

• Yields

• Products

• Chemical equation

How many Mn atoms are found in the following compound?

2MnO₄

• 1

• 2

• 4

• 8

What is the little number after an element in a chemical equation called?

Example: H₂

• Coefficient

• Atom

• Subscript

• Equation

How many HCl molecules do you need to balance this equation? 
Mg +  __HCl --->  MgCl₂ + H₂

• 1
• 2
• 3
• 4

The temperature at which a substance changes from the liquid phase to the gas phase

• boiling point

• melting point

• freezing point

• dew point

A pure substance made of only one kind of atom

• element

• compound

• molecule

• product

The following are the evidences that chemical reaction took place, EXCEPT:

• evolution of gas

• formation of precipitate

• formation of new element

• change in the intrinsic properties