Chapter 14, Section 2: Chemical Formulas and Equations
About how many elements make up all known substances?
100
How many oxygen atoms are contained in the formula 2H2O?
2
Nitrogen dioxide is a covalent compound. How many oxygen atoms are in a nitrogen dioxide molecule?
2
The symbol for iron is Fe. The chemical symbol for oxygen is O. The formula for iron oxide is Fe2+O3. How many iron atoms are in one molecule of iron oxide?
2
How many oxygen atoms are present in the reactant side of the chemical equation 4Fe+3O2 ->2Fe2 O3
6
What does a chemical formula show?
A chemical formula shows how many atoms of each molecule of each kind are present in a molecule.
The overall charge of an ionic compound is:
Zero
What will happen if the wrong chemical symbol or formula is used in a chemical equation?
It will wrongly describe the reaction that is occurring.
Antoine Lavoisier's work led to the __________________________________.
Law of Conservation of Mass
Which of the following states the law of conservation of mass?
Mass cannot be created or destroyed in a chemical reaction
What does the law of conservation of mass state?
Mass cannot be created or destroyed in ordinary chemical and/or physical changes
magnesium chloride
MgCl
Which of the following uses coefficients correctly to balance the equation N2+H2 ->NH3
N2+3H2 ->2NH3
The formula for dinitrogen monoxide is:
N2O
Which of the following is the product in the chemical equation N+O2 ->NO2?
NO2
sodium chloride:
NaCl
Ionic compounds are composed of a(n) ___________________and a(n) ______________________.
metal; nonmetal
Covalent compounds are usually composed of two __________________.
nonmetals
A substance that forms in a chemical reaction is called a(n):
product
When carbon and oxygen react to form carbon dioxide, the carbon dioxide is the:
product
A substance or molecule that participates in a chemical reaction is called a(n):
reactant
What is the charge of an ionic compound?
zero
What is the chemical formula for glucose?
C6H12O6
The formula for carbon dioxide is:
CO2
A calcium carbonate molecule has 1 calcium (Ca) atom, 3 oxygen (O) atoms, and 1 carbon (C) atom. Which of the following shows the chemical formula for calcium carbonate?
CaCO3
What is the chemical formula for water?
H2O
What is the chemical formula for oxygen?
O2
What do musical notations and chemical equations have in common?
They both use symbols to communicate info in ways that are easy to understand by people who can read those symbols, no matter what language they speak.
A chemical equation must show the same numbers and kinds of ____________ on both sides of the arrow.
atoms
In a chemical reaction, ___________ are never gained or lost.
atoms
The subscript in the chemical formula H2O tells you there are two
atoms of hydrogen in the molecule
When chemical symbols and formulas are used as a shortcut to describe a chemical reaction, It is called a(n):
chemical equation
A combination of chemical symbols and numbers that represent a substance is called a(n)
chemical formula
The number placed in front of a chemical symbol or formula is called a(n):
coefficient
When balancing an equation, only ______________________ are changed, not _______________________.
coefficients; subscripts
