Unit 2 Test Notes Flashcards
What is a Double Displacement Reaction?
A reaction in which elements in two compounds displace each other or trade places, producing two new compounds.
In what type of solutions do Double Displacement Reactions commonly occur?
Aqueous solutions.
What are the three types of Double Displacement Reactions?
- Precipitation Reactions
- Reactions that produce a Gas
- Neutralization Reactions
Define Precipitate.
A solid (s) formed from a reaction that takes place in solution.
What is Solubility?
A measure of the maximum amount of solute that will dissolve in a known amount of solvent at a given temperature and pressure.
What happens when two solutions react in a Precipitation Reaction?
The cations in one solution attract and bond to the anions in the other solution, forming a new compound that may be slightly soluble and thus forming a precipitate.
What can be done to treat water contaminated with toxic metal ions?
Choose a reactant that will react to form a precipitate containing the toxic ion, which can then be filtered out.
What indicates that no reaction has occurred in a Double Displacement Reaction?
If a precipitate does NOT form, then no reaction has occurred.
What can produce a gas in Double Displacement Reactions?
Reactions involving acids, as well as the decomposition of unstable products.
What is a Neutralization Reaction?
The reaction of an acid and a base where the resulting solution has a pH closer to 7 than either of the reactants.
Fill in the blank: A Double Displacement Reaction that produces water and an ionic compound is known as a _______.
[Neutralization Reaction]
True or False: Double Displacement Reactions can only occur in solid solutions.
False.
What is the significance of the table found at the back of the periodic table?
It summarizes the combinations of cations and anions, indicating which are highly soluble and which are only slightly soluble.
What is the result of the reaction between sulfides, carbonates, or sulfites with an acid in a DD reaction?
They will produce a gas.
What is the chemical formula for water in the context of a Neutralization Reaction?
H2O.
What is a Single Displacement Reaction?
A reaction in which an element displaces another element in a compound producing a new element.
What is the purpose of Single Displacement Reactions?
Useful for recovering a dissolved metal from a solution.
What does the Activity Series of Metals indicate?
A list of elements arranged in order of their observed reactivity in single displacement reactions.
Which metals are at the top of the Activity Series?
Lithium and Potassium.
Why is Hydrogen included in the Activity Series of Metals?
Because it can form a positively charged ion just like a metal.
What are the two important generalizations of the Activity Series?
- One element can displace elements below it from compounds in solution but cannot displace elements above it.
- The farther apart two elements are, the more likely it is that the displacement reaction will occur quickly.
What happens if the higher (more active) metal is the element in a reaction?
The reaction proceeds.
What happens if the higher metal is in the compound in a reaction?
No reaction occurs.
Fill in the blank: The halogen family has their own activity series that matches their order on the _______.
periodic table.
What should you treat acids and water like when they are reacting with metals?
Ionic compounds.
True or False: If magnesium metal is placed in a solution of copper(II) sulfate, a reaction occurs.
True.
In the context of the Activity Series, what occurs when lead is placed in a zinc nitrate solution?
No reaction.
What is the acronym for the molecular elements that should be remembered?
HOFBrINCl.
What is the chemical equation for lithium added to sulfuric acid using the activity series?
Li + H2SO4 → Reaction occurs.
What is the chemical equation for sodium added to water using the activity series?
Na + H2O → Reaction occurs.
What is a synthesis reaction?
A chemical reaction in which two or more substances combine to form one more complex substance
Sometimes referred to as a combination reaction.
What is an example of a synthesis reaction involving a metal and a non-metal?
Metal + Non-metal → Binary compound
The direct union of two elements will produce a binary compound.
Write the balanced chemical equation for the synthesis reaction of magnesium and oxygen.
2 Mg + O2 → 2 MgO
This demonstrates a synthesis reaction between magnesium and oxygen.
What is the result of a synthesis reaction between metallic oxides and water?
Metallic oxide + H2O → Metal hydroxide (basic solution)
Metallic oxides are always solids and react with water to form basic solutions.
What is produced when metallic oxides react with carbon dioxide?
Metallic oxides + CO2 → Metal carbonates
This is an example of a synthesis reaction involving carbon dioxide.
What is the general form of a synthesis reaction involving a non-metal and oxygen?
Non-metal + Oxygen → Non-metallic oxide
Non-metallic oxides are often gases and liquids and react with water to form acidic solutions.
What happens during the decomposition of binary compounds?
A large or more complex compound breaks down to form two or more simpler products
These reactions usually need energy to get started.
What do metal chlorates decompose into when heated?
Metal chlorides and oxygen
Example: 2 KClO3 → 2 KCl + 3 O2.
What do some acids decompose into when heated?
A nonmetal oxide and water
Example: H2CO3 → CO2 + H2O.
What do metal hydroxides decompose into when heated?
Metal oxides and water
Example: Ca(OH)2 → CaO + H2O.
What do metal carbonates decompose into when heated?
Metal oxides and carbon dioxide
Example: MgCO3 → MgO + CO2.
Classify the reaction: 2 AI + 3 Br → 2 AIBr3.
Synthesis
This reaction combines elements to form a compound.
Classify the reaction: 2 HCl → H2 + Cl2.
Decomposition
This reaction breaks down a compound into simpler substances.
Classify the reaction: CaO + H2O → Ca(OH)2.
Synthesis
This reaction combines calcium oxide with water to form calcium hydroxide.
Classify the reaction: P4 + 5 O2 → 2 P2O5.
Synthesis
This reaction involves the combination of phosphorus and oxygen to form a compound.
What is a combustion reaction?
A chemical reaction in which a fuel (hydrocarbon) burns in oxygen to produce carbon dioxide, water, and energy.
What are the two types of combustion?
- Complete Combustion
- Incomplete Combustion
What must be present for a combustion reaction to occur?
- Fuel
- Oxygen
- Heat
Define hydrocarbon.
A compound containing hydrogen and carbon, serving as a reactant in a combustion reaction.
What are the products of complete combustion?
- Water vapour (H2O (g))
- Carbon dioxide gas (CO2 (g))
- Energy
What occurs during incomplete combustion?
It occurs when there is a limited supply of oxygen.
List the possible products of incomplete combustion.
- Water vapour (H2O (g))
- Carbon dioxide gas (CO2 (g))
- Carbon monoxide (CO (g))
- Soot (C (s))
- Energy
What is a concern of incomplete combustion?
It releases only a portion of the energy that could be obtained from the fuel.
True or False: Soot particles from incomplete combustion are an inhalation hazard.
True
What is carbon monoxide known as and why?
The ‘silent killer’ because it is a toxic gas.
What greenhouse gas is produced by combustion reactions?
Carbon dioxide (CO2)
Define greenhouse gas.
Any of several gases that allow solar radiation to pass through the atmosphere but absorb radiation emitted by Earth, trapping thermal energy.
How does combustion contribute to global warming?
By producing carbon dioxide, a greenhouse gas that traps thermal energy.
What is the role of combustion reactions in everyday life?
They power and heat our homes and transport us.
What is the complete combustion of glucose used for?
It produces energy used by living things to carry out functions.
Write the balanced chemical equation for the complete combustion of octane (C8H18).
2 C8H18 (l) + 25 O2 (g) → 16 CO2 (g) + 18 H2O (g)
What will the products of a complete combustion always be?
- Carbon dioxide gas
- Water vapour
Fill in the blank: Incomplete combustion produces _______.
carbon monoxide (CO) and soot (C (s))
What is the outcome of balancing combustion reactions?
The elements must be balanced on both reactants and products side.
Determine the subscripts X & Y in the complete combustion reaction: CxHy + 8 O2 (g) → 5 CO2 (g) + 6 H2O (g).
C5H12
What is a chemical reaction?
A process in which one or more substances change into one or more new substances.
List five clues that may indicate a chemical change.
- Unexpected change in colour
- Change in odour
- Energy is released or absorbed
- A gas is produced
- A precipitate is formed
What does the Collision Reaction Theory state?
Chemical reactions involve collisions and rearrangements of atoms or groups of atoms.
What factors affect the outcome of collisions in chemical reactions?
- Energy
- Orientation
True or False: A reaction will occur if there is not enough energy or if the molecules do not collide in the right orientation.
True
What is the Law of Conservation of Mass?
During a chemical reaction, the total mass of reactants is equal to the total mass of the products.
What is a catalyst?
A substance that makes a reaction occur faster without itself being consumed in the reaction.
What is a word equation?
A representation of a chemical reaction using only the names of chemicals involved.
Provide an example of a word equation.
Liquid octane (C8H18) reacts with oxygen gas to produce carbon dioxide gas and water.
What is a balanced chemical equation?
A representation of a chemical reaction that indicates the chemical formulas, relative number of entities (coefficients), and states of matter of the reactants and products.
How are coefficients used in balancing chemical equations?
They indicate the ratio of molecules or formula units of each substance involved in a chemical reaction.
What should never change when balancing chemical equations?
The subscripts of compounds.
List some hints for balancing chemical equations.
- Balance atoms occurring in only one compound on either side
- Balance whole groups of polyatomic ions whenever possible
- Balance atoms and groups one at a time
- Always recount atoms when done balancing
Fill in the blank: Ammonia is _______.
NH3
What is the first step in balancing a chemical equation?
Balance the atoms that occur in only one compound on either side of the reaction.
True or False: You should change the subscripts of compounds when balancing equations.
False
