Chapter 7 chemical reactions
Combustion reactions can also be identified as other reactions too
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Never change the formula to balance an equation!!!
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Reminder atomic mass is the total number of protons and neutrons in the atom
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Sometimes one of the products in a double reaction will decompose
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Example of a combustion
2H2 + O2 -> 2H2O
Examples of a synthesis reaction:
2H2 + O2 -> 2H2O
Examples of a decomposition:
2H2O-> 2H2 + O2
General equation for a single replacement reaction:
A + BC -> B + AC
When a substances undergoes a chemical change
A chemical reaction takes place
The reactants in a decomposition must be
A compound
Mass is
A measure of matter
Synthesis reaction:
A reaction in which two or more substances react to form a single substance (product)
Synthesis general equation:
A+B-> AB
General equation for a double replacement:
AB + CD -> AD + CB
General equation for a decomposition
AB-> A+B
Molar mass for compounds is found by
Adding up the atomic mass of the elements in the compound and expressing the sum in grams
You will ___ get the same product of a CCHC
Always
During a chemical reaction, the mass of the product is
Always equal to mass of the reactants
A mole is
An amount of a substance that contains approximately 6.02 x 10 (23) particles of that substance
In order to show that mass is conserved during a reaction
An equation must be balanced
The number (6.02 x 10(23) is called
Avogadro's number
Reactions are often classified how?
By the type of reactant or the number of reactants or products
Complete combustion of a hydrocarbon (CCHC)
CH4 + O2 -> CO2 + H2O
Example of double reaction decomposing:
CaCO3 + 2HCl -> CaCl2 + H2CO3 -> CaCl2 + H2O + CO2
You balance a chemical equation by
Changing the coefficients of the formula
Molar mass is used to
Convert between molar and mass amounts of one substance
Examples of a single replacement reaction:
Cu + 2AgNO3 -> Ag + Cu(NO3)
The reactants in a synthesis reaction can be
Elements or compounds
The number of atoms on the reactant side of the equation must
Equal the number of atoms on the product side of the equation
A word equation
Gives the names of the reactants and products involved in the reaction
When you have an alkali metals + water ->
H2 + metallic hydroxide
The particles (in chemistry) can be
Ions, atoms, or molecules
What is a hydrocarbon
Is a compound made of hydrogen and carbon
A chemical equation
Is a representation of a chemical reaction in which the reactants and products are expressed as formulas
Molar mass
Is the same as the atomic mass expressed in grams
A mole ratio
Is used to convert between molar amounts of two different substances in a chemical reaction
Why is the alkaline metals and water equation different from the others when it comes to the product?
Metallic hydroxide is produced
The mass of one mole of a substance is called a
Molar mass
Because chemical equations involve large number of particles, chemists use a county unit called ____ to measure the amount of the substance
Mole
Combustion reaction:
One in which a substance reacts rapidly with oxygen, often produces heat and light
Decomposition reaction:
Opposite of synthesis reaction, reaction in which a compound breaks down into two or more simpler substances
Examples of a double replacement:
Pb(NO3)2 + 2KI -> PbI2 + 2KNO3
The new substance formed as a result of the chemical change are called
Products
In a chemical reaction, the substances that undergo changes are called
Reactants
Single replacement reaction:
Reaction in which one element takes the place of another element in the compound
Double replacement reaction:
Reaction is one in which 2 different compounds exchange positive ions and form 2 new compounds
The law of conservation of mass
States that mass is neither created in a chemical reaction
The general types of reactions are:
Synthesis, decomposition, single replacement, double replacement, and combustion
Why is metallic hydroxide produced?
The hydrogen gas will explode because of the heat produced by the reaction
The law is also called
The law of conservation of matter
The statement listed above us known as
The law of the conservation of mass
Why do they have to have the same amount?
To show that mass is conserved
In chemical reactions, the mass of a reactant or product can be calculated by
Using a balanced chemical reaction and the molar masses of the reactants and products
The -> means
Yields
The product in a decomposition reaction can be
elements or compounds
