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What law must chemical equations obey, making them balanced?

the Law of Conservation of Matter

What are the five types of reactions?

synthesis, decomposition, single replacement, double replacement, and combustion

What are the diatomic molecules?

Hydrogen, Nitrogen, Oxygen, Fluorine, Chlorine, Bromine, Iodine

What does the + sign mean?

it is used to separate 2 reactions or 2 products

What does the --> sign mean?

"yields," separates reactions from products

What does (s) stand for?

a designated reaction or product in the solid state; placed after the formula

What does (l) stand for?

a reaction or product in the liquid state; placed after the formula

What does (g) stand for?

a reaction or product in the gas state; placed after the formula

What does (aq) stand for?

designates an aqueous solution; placed after the formula

What is an aqueous solution mean?

the substance is dissolved in water

What is a word equation?

used to describe chemical changes, or represent a chemical equation

What is a skeleton equation?

does not indicate the relative amounts of the reactants and products

What is a chemical equation?

a shorthand expression describing a chemical reaction

What is a reactant?

the beginning substances; always written on the left of the equation

What is a product?

the ending substances; always to the right of the equation

What does a coefficient indicate?

the relative amounts of a molecule or compound involved in a chemical reaction

What does a subscript indicate?

the number of atoms of an element in a chemical formula

WHat is a catalyst?

a susbstance that speeds up the rate of a reaction buy is not consumed

What is an inhibitor?

a substance that slows doen a chemical reaction or prevents it from happening

What is an exothermic reaction?

it releases energy in the form of hear or light (feels hot)

What is an endothermic reaction?

it absorbs energy (feels cold)

What is the balanced equation and type of reaction to the following equation:
Hydrogen gas reacts with Bromine gas to produce Hydrogen bromide gas ?

H2 + Br2 --> 2HBr

What is the the balanced equation and identify the type of chemical reaction of the following equation:
Aluminum oxide (s) decomposes when electricity is passed through it ?

2Al2O3 --> 4Al + 3O2

What is the balanced equation to the following rxn:
P4 (s) + Br2 (l) --> PBr5 (s) ?

P4 + 10Br2 --> 4Br5

What are the 6 signs to a chemical change?

color change, heat-energy released, odor, bubbling of gas, absorption of energy, and solid precipitation

Substances that prevent the chemical reactions are called... ?


Which reaction does not occur?
a) 2HF + Cl2 --> F2 +2HCL
b) 2Na + ZnF2 --> 2NaF + Zn
c) Fe +CuCl2 --> FeCl2 + Cu
d) 2HCl + Mg --> MgCl2 +H2

a) 2HF + Cl2 --> F2 + 2HCl

A chemical reaction in which energy is released is...?


According to the law of conservation of mass, if two atoms of hydrogen are used as a reactant, how many atoms of hydrogen must be a part of the product?


In the equation 2Al (s) + 3FE(NO3)2 (aq) --> 3Fe (s) + 2Al(NO3)3 (aq), iron has been replaced by...?


Predict the product o fthe following reaction: MgO + CO2 -->


What is the formula equation for the formation of carbon dioxide from carbon and oxygen?

C + O2 --> CO2

What type of reaction is shown in the following chemcial equation? NH2 + HCl --> NH4Cl


Which coefficients correctly balance the formula equation NH4NO2 (s) --> N2 (g) + H2O (l)?


When a slightly soluble solid compound is produced in a double-replacement reaction, a __________ is formed.


The reaction Pb(NO3)2 (aq) + 2KI (aq) -->PbI2 (s) + 2KNO3 (aq) is a ...?

double-replacement reaction

What can be predicted by using an activity series?

whether a certain chemical reaction will occur

To balance a chemical equation, it may be necessary to adjust the ...?


Magnesium hydroxide decomposes to yield magnesium oxide and ...?

water (H2O)

The reaction Mg (s) + 2HCl (aq)
--> H2 (g) + MgCl2 (aq) is a

single-replacement reaction

A chemical reaction has not occurred if the products have...?

the same chemical properties as the reactants

What happens when zinc is added to water?

no reaction occurs

A substance that speeds up a chemical reaction without undergoing a permanent change itself is...?

a catalyst

What happens when calcium metal is added to a solution of magnesium chloride?

calcium chloride forms

In what kind of reaction does one element replace a similar element in a compound?

single replacement reaction

When sodium chlorate (NaClO3) decomposes, what are the products?

sodium chloride and oxygen

What is the general structure of synthesis reactions?


What is the general structure of decomposition reactions?


What is the general structure of single-replacement reactions?


What is the general structure of double-replacement reactions?


What is synthesis?

two or more substances combined to form a more complex substance

What is decomposition?

a single substance broken down into two or more simpler substances

What is single-replacement?

a free element replaces a less active element in a compound

What is double-replacement?

the elements of reacting compounds replace each other

What do combustion reactions involve?

the reaction of a substance with oxygen that usually produces heat & light

What is another name for double-replacement reactions?

metathesis reactions

What is precipitate?

an insoluble solution

When balancing equations, which atoms must be balanced last?

hydrogen and oxygen

What must happen for a reaction to proceed?

reactants' bonds must break, and bonds must reform to make products

Reactions either ______ or ______ energy, they never stay the same.

gain; lose

What is activation energy?

the energy required to break bonds

Activation energy is always __________.


What is the difference between the energy of reactants and products?

the total heat or energy of the reaction

What is the energy required to break the reactants' bonds?

activation energy

What is the point at which all bonds have been broken and products begin to reform?

activated complex

What affect do catalysts have on the activation energy of a reaction?

it lowers the activation energy

On an energy diagram, how do you know if the reaction is exothermic?

the energy level at the end of the reaction is lower than the energy level at the beginning of the reaction

On an energy diagram how do you know if the reaction in endothermic?

the energy level at the end of the reaction is higher than the energy level at the beginning of the reaction

Exothermic reactions always have _________ change in heat values.


Endothermic reactions always have _________ change in heat values.


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