Chapter 19
How do you indicate that a substance in an equation is a solid?
(s)
In the reaction C2H2(g) + H2O(g) ↔ CH3CHO(G) + energy the product is found to increase from 0.0300 mol/L to 0.0500 mol/L in 42.5 s. Express the average rate of the reaction in mol/(L•s).
0.00047
Ten grams of mercury(II) oxide react to produce 9.3 g of mercury and oxygen. What is the mass of the oxygen produced?
0.7 g
How many grams are in of 3.000 mol of calcium?
120.234
If an endothermic reaction at 26°C and decreases by 2°C per minute, how long will it take to reach 0°C?
13
If an endothermic reaction at 26°C and decreases by 2°C per minute, what would the temperature be, in °C, after 5 minutes?
16
When 46g of sodium is exposed to dry air, 62g of sodium oxide formed. What mass of oxygen was used in grams?
16
What is the molar mass of Cu(NO3)2 in g/mol?
187.57
If one mole of oxygen gas is used in the reaction, 2H2 + O2 → 2H2O, how many moles of water are produced?
2
What are the coefficients, in order, that would balance the equation: __Fe(s) + __Cl2(g) → __FeCl3(s)?
2, 3, 2
How many moles are in 4609g of Cu(NO3)2?
2.5
Write the balanced equation for the reaction of hydrogen gas and oxygen gas that forms water.
2H2(g) + O2(g) → 2H2O(l)
Which is the correct chemical chemical equation for the reaction shown?
2H2O(l) → 2H2(g) + O2 (g)
HCl is slowly added to adequeos Na2CO3 forming NaCl, H2O, and CO2. Write a balanced equation for this reaction.
2HCl(aq) + Na2CO2(aq) → 2NaCl(aq) + H2O(s) + CO2(g)
Balance this equation: NaOH(aq) + CaBr2(s) → Ca(OH)2(s) + NaBr(aq)
2NaOH(aq) + CaBr2(s) → Ca(OH)2(s) + 2NaBr(aq)
The following chemical equation is balanced, but its coefficients are larger than necessary. Rewrite this balanced equation using the smallest coefficients possible. 9Fe(s) + 12H2O(l) → 3Fe3O4(s) + 12H2(g)
3Fe(s) + 4H2O(l) → Fe3O4(s) + 4H2(g)
How many particles are in one mole of a substance?
6.02 × 1023
How many moles are in 125g of water?
6.94
What symbols represent a synthesis reaction?
A + B → AB
Which of the following general formulas represents a single-displacement reaction?
A + BC → AC + B
_______ is a way to describe a chemical reaction using chemical formulas and symbols.
A chemical equation
Which substance is the precipitate in the reaction Ba(NO3)2(aq) + K2SO4(aq) → BaSO4(s) + 2KNO3(aq)?
BaSO4
A sample of barium sulfate (BaSO4) is placed on a piece of paper, which is ignited. Barium sulfate reacts with the carbon from the burned paper producing barium sulfide (BaS) and carbon monoxide (CO). Pick the balanced equation for this reaction.
BaSO4(s) + 4C(s) → CaS(s) + 4CO(g)
How can an endergonic reaction NOT be endothermic?
Both require energy to happen. Endergonic energy can come in several forms. Endothermic reactions only requires heat.
Which reactions are combustion?
C10H8(l) + 12O2(g) → 10CO2(g) + 4H2O(g)
Which of these is a balanced chemical equation?
CH4 + 2O2 → CO2 + 2H2O
Which reactions are synthesis?
CaO(s) + H2O (l) → Ca(OH)2(aq)
Why doesn't the total amount of energy decrease in and exergonic chemical reaction?
Energy just changes forms, none is lost
Which reactions are single displacement?
Fe(s) + CuSO4(aq) → FeSO4(aq) + Cu(s)
if a stress is applied to a system in equilibrium the equilibrium shifts in the direction of the stress
Le Chatelier principle
Balance this equation: MgCl2(aq) + AgNO3(aq) → Mg(NO3)2(aq) +AgCl(s).
MgCl2(aq) + 2AgNO3(aq) → Mg(NO3)2(aq) +2AgCl(s)
Which reactions are decomposition?
NH4NO3(S) → N2O(g) + 2H2O(g)
Which reactions are double displacement?
NaCl(aq) + AgNO3(aq) → NaNO3(aq) + AgCl3(s)
Why must O2 be used in chemical equations instead of O?
Oxygen is a diatomic atom and exists in pairs not alone.
Which substance is the precipitate in the following reactions? Pb(NO3)2(aq) + Na2SO4(aq) → PbSO4(s) + 2NaNO3(aq)
PbSO4
Classify the chemical reaction photosynthesis as endergonic or exergonic. Explain.
Photosynthesis is endergonic because it requires the addition of energy (in the form of light) in order to move forward.
Sulfur trioxide (SO3), a pollutant released coal burning plants, can react with water (H2O) in the atmosphere to produce sulfuric acid (H2SO4). Write the balanced equation for the reaction.
SO3(g) + H2O(g) → H2SO4(g)
How does synthesis & decomposition reactions compare?
Synthesis involves bringing elements together to make compounds. Decomposition involve breaking down compounds to make elements.
What is the effect of increasing the temperature of a chemical reaction?
The rate of the reaction is increased.
Identify a possible economic impact of redox reactions. How might that impact be lessened?
Things made of iorn can rust. It can be prevented by coating the iron with something oil or another substance that keeps oxygen away from it.
Will zinc will displace gold in a chemical reaction. Why or why not?
Zinc will displace gold because it is more reactive than gold.
What happens in a combustion reaction?
a substance combines with oxygen to produce water, carbon dioxide, giving off energy
What is the name of the energy that is required to start a chemical reaction?
activation energy
a chemical equation with the same number of atoms of each element on both sides of the arrow
balanced chemical equation
Which of the following metals would most likely replace iron in a solution?
calcium
What is the name of the compound that has the formula CaSO4?
calcium sulfate
A reversible reaction is a chemical reaction that _______.
can occur in both forward and reverse directions
a substance that speeds up a chemical reaction without being permanently changed itself
catalyst
a way to describe a chemical reaction using chemical formulas and other symbols
chemical equation
Compare & contrast chemical and physical equilibrium.
chemical equilibrium is when forward reactions = reverse directions; physical equilibrium is when physical changes happen in both directions at the same rate
A change in which one or more substances are converted into new substances is a _______.
chemical reaction
a change where substances change into different substances
chemical reaction
the number of units of each substance taking part in a reaction
coefficient
Why doesn't the sum of the coefficients of the products not have to equal the sum of the coefficients of the reactants?
coefficients represent number of particles, not number of atoms
atoms, ions, and molecules must collide in order to react
collision model
Which explains why increasing reaction concentration leads to increased reaction rate?
collision theory
occurs when a substance reacts with oxygen to produce energy in the form of heat and light _?C? + _O → _H2O + _CO2 + Energy
combustion reaction
What law is demonstrated by Lavoister's experiment pictured?
conservation of mass
How can this chemical reaction be classified?
decomposition
The formula AB → A + B represents what type of chemical reaction?
decomposition
Which of the following is the correct classification for the chemical reaction that occurs when an electric current passes through water: 2H2O → 2H2 + O2
decomposition
Which of the following types of reactions is the opposite of the synthesis reaction?
decomposition
occurs when one substance breaks down, or decomposes, into two or more substances AB → A + B
decomposition reaction
What type of reaction occurs when the positive ion of one compound replaces the positive ion of another to form two new compounds?
double displacement
What kind of chemical reaction is pictured?
double-displacement
AB + CD → AD + CB
double-displacement reaction
Classify the following chemical reaction: energy + reactants → products.
endergonic
reactions that require more energy than they give off (energy can be in the form of light, heat, or electricity)
endergonic reactions
when the energy required for a reaction to happen is in the form of thermal energy (heat)
endothermic reaction
Which type of reaction requires the addition of thermal energy to continue?
endothermic reactions
a state in which forward and reverse reactions or processes proceed at equal rates
equilibrium
Classify the reaction that makes a firefly glow in terms of energy input & output.
exergonic
chemical reactions that release energy
exergonic reaction
when the energy given off in a reaction is primarily in the form of thermal energy
exothermic reaction
To develop a product that warms people's hands, would you use an exothermic or endothermic reaction? Why?
exothermic; it would release energy to warm hands
The law of conservation of mass states that _______.
in a chemical reaction, matter is not crated or destroyed, but is conserved
An increase of the concentration of one or more of the reactants in a chemical reaction _______.
increases the reaction rate because there are more opportunities for reacting particles to collide
Which increases the rate at which reactions take place?
increasing surface area
IN the chemical reactions leading to food spoilage, which role do food preservatives play?
inhibitor
Which type of compound is the food additive BHA that acts as a preservative?
inhibitor
substances used to slow down the rates of chemical reactions or prevent a reaction from happening at all
inhibitor
What is the importance of the law of conservation of mass?
it explains why matter in the universe does not go away
Which of the metals in the activity series shown would you expect to be the least likely to be found as a relatively pure element?
lithium
Which of these processes is endothermic?
mixing Epson salt in water
the mass in grams of one mole of a substance
molar mass
the amount of a substance that contains 6.02 x 1023 particles of a substance
mole
the loss of electrons
oxidation
Which metal would most likely replace lead in a solution?
potassium
An insoluble compound that comes out of solution during a double displacement reaction is called a _______.
precipitate
insoluble compound that comes out of a solution during a double-displacement reaction
precipitate
Pick two ways the reaction is affected by Le Charelier's principle. C2H2(g) + H2O(g) ↔ CH3CHO(G) + energy
pressure would drive reaction forward; heating a closed container would also drive the reaction forward
New substances produced by a chemical reaction are _______.
products
the ending substances in a chemical change
products
What are two ways to state the rate of chemical reactions?
rate at which the reactants are being concumed and the rate at which the products are being produced
the starting substances of a chemical reaction
reactants
What are the reactants and the products in Cd(NO3)2(aq) + H2S(s) → CdS(s)+ 2HNO3(aq)
reactants: Cd(NO3)2, H2S products: CdS, 2HNO3
rate at which reactants turn into products
reaction rate
the gain of electrons
reduction
When bonds form in a chemical reaction, energy is _______.
released
one that occur in both the forward and reverse directions
reversible reaction
Which of the metals would you expect to be found in nature as a deposit of a relatively pure element?
silver
A + BC → AC + B
single-displacement reaction
In the formula for aluminum chloride, AlCl3, the number "3" is a _______.
subscript
Oxygen gas is always written as O2 in chemical equations. What term is used to describe the 2 in this formula?
subscript
In a _______ reaction, two or more substances combine to form another substance.
synthesis
Which of the following types of reactions is the opposite of a decomposition reaction?
synthesis
two or more substances combine to form another (single) substance A + B → AB
synthesis reaction
Pick the main thing your book says affect reaction rate.
temperature, the higher the temperature, the faster the motion, the faster the reaction, concentration, the higher the concentration, the more often particles collide, the faster the reaction rate, volume & pressure, the higher the pressure the lower the volume, the closer the particles, the more often they collide, the higher the reaction rate surface area, grind it up and the reaction rate increases, caatalysts speed up reactions, inhibitors slow down or stop reactions
The reaction rate is _______.
the rate at which reactants are changed into products
If you know that dissolving ammonium nitrate in water is an endothermic reaction, then you know that _______.
the temperature of the product is lower than the temperature of the reactants
What must happen in order for molecules to react?
the two molecules must collide with sufficient energy in order to react
Which form of energy is produced by an exothermic reaction?
thermal energy
Which best describes the reactants and products in a reaction at equilibrium?
they form at equal rates
A catalyst is _______.
used to increase reaction rate
For reactions between gases, decreasing the _______ increases the pressure and the reaction rate.
volume
