Module 04 : Reactions Flashcards
The reaction 2NO(g) + O2(g) → 2NO2(g) is a synthesis reaction. (2 points)
True
False
True
What is true of synthesis and decomposition reactions? (4 points)
- Synthesis reactions require more energy than decomposition reactions.
- Synthesis reactions produce more products than decomposition reactions.
- Synthesis reactions are the opposite of decomposition reactions.
- Synthesis reactions have fewer reactants than decomposition reactions.
3. Synthesis reactions are the opposite of decomposition reactions.
A synthesis reaction can be identified because it only has pure elements on the left side of the arrow and compounds on the right side of the arrow. (2 points)
- True
- False
False
Which chemical equation correctly represents the synthesis of calcium sulfite from calcium oxide and sulfur dioxide? (4 points)
- CaSO3(s) → CaO(s) + SO2(g)
- CaSO3(s) + O2(g) → CaO(s) + SO2(g)
- CaO(s) + SO2(g) → CaSO3(s)
- CaO(s) + SO2(g) → CaSO3(s) + O2(g)
3. CaO(s) + SO2(g) → CaSO3(s)
Which of the following is a synthesis reaction? (4 points)
- AgNO3 + NaCl → AgCl + NaNO3
- CH4 + O2 → CO2 + H2O
- SO3 + H2O → H2SO4
- Cu + AgNO3 → Ag + CuNO3
3. SO3 + H2O → H2SO4
An unbalanced chemical equation is shown:
H2O2 → 2H2O + O2
Which of the following statements explains why the equation is not balanced? (4 points)
- Two H2O2 molecules should decompose to form the given products.
- Four H2O2 molecules should decompose to form the given products.
- Two H2O2 molecules should undergo a synthesis reaction to form the given products.
- Four H2O2 molecules should undergo a synthesis reaction to form the given products.
1. Two H2O2 molecules should decompose to form the given products.
Define a Synthesis Reaction:
Synthesis Reaction: reaction two+ reactants combine to form one product
A + B → AB
Define Decomposition reaction:
Decomposition Reaction: Single compound reactant to form more than one product
AB → A + B
What are the components of Chemical equations?
A chemical reaction involves bonds being broken and formed as atoms rearrange to make new substances
Reactant: Initial substance before chemical change
Product: New substance after a chemical change
Define Chemical Change:
- Left to right
- Represented in chemical formulas
- The phase of each substance indicated in subscripts
(s) for solid, (l) for liquid, and (g) for gas
(aq) → aqueous solution → compounds dissolved in water to forma solution
Define the Law of Conservation of Mass:
Law of Conservation of Mass: Mass cannot be created or destroyed within a closed system
- In chemical equations: equal number of elements on both sides of the equation
- in experiments the initial weight/volume will be the same total at the end
Fill in the blank with the correct number to balance the equation: 4Cr + 3O2 → Cr2O3. (Enter only a whole number.) (3 points)
2
For the reaction VCl2 + Cl2 → VCl5, what are the reactants, products, and correct coefficients in the balanced equation? (3 points)
- Reactants: 2VCl2 and 3Cl2; product: 2VCl5
- Reactants: 2VCl2 and 1Cl2; product: 2VCl5
- Products: 1VCl2 and 2Cl2; reactant: 1VCl5
- Products: 2VCl2 and 1Cl2; reactant: 2VCl5
1. Reactants: 2VCl2 and 3Cl2; product: 2VCl5
Which of the following laboratory procedures best illustrates the law of conservation of mass? (Assume the product of the reaction includes the mass of any unused reactants.) (3 points)
- Calculating the number of atoms in 11 g of Na
- Using 250 g of impure Cu to obtain 200 g of pure Cu
- Heating 32 g of S and 56 g of Fe to produce 88 g of FeS
- Burning 2.4 g of Mg in an open crucible to produce 2 g of MgO
3. Heating 32 g of S and 56 g of Fe to produce 88 g of FeS
A chemical equation is shown:
Al + O2 → Al2O3
According to the law of conservation of mass, how many atoms of oxygen exist in the products of this reaction? (3 points)
- 6
- 5
- 3
- 2
- 6
When methane, CH4, is combusted, it produces carbon dioxide, CO2, according to the unbalanced equation: CH4 + O2 → CO2 + H2O.
Write the balanced equation for this reaction, and explain how it is possible for 10 grams of methane fuel to burn and emit 27 grams of carbon dioxide. Discuss whether or not this reaction obeys the law of conservation of mass. (5 points)
In the equation above, there are 4 hydrogen atoms on the left side and only two on the right; therefore, a coefficient of 2 has to be added before the compound H20. Now the equation is as follows: CH4 + O2 → CO2 + 2H2O. On the right side of the equation, there are 4 oxygen atoms now and only two on the left, so a coefficient of two has to be added to the left oxygen atom to make it equal to four: CH4 + 2O2 → CO2 + 2H2O. There is 1 carbon atom on the left and the right, so the element is balanced. Since, according to the Law of Conservation of Mass, the energy/amount of atoms has to stay the same, the balanced equation is CH4 + 2O2 → CO2 + 2H2O.
All reactions have to obey the Law of Conservation of Mass, so even when the transfer of matter is not clear; therefore, the reaction above has to make logical sense in some way or another. Even though the methane in the initial reactants weighed less than the CO2, the diatomic oxygen atom also contributed to the reactants’ weight, so the carbon chemically reacted with the oxygen, which is why it weighs more in the product than the reactant.
Define Single Replacement Reactions:
- What is the formula
- and the components of the formula
Reaction one element replaces a similar element in a compound
A + BC → AC + B
- A → neutral element
- BC → ionic compound
- Positive ion A replaces positive ion B in ionic compound
Define Double Replacement Reactions:
- What is the formula
- and the components of the formula
Reaction in which ions of two compounds exchange places in aqueous solution to form two new compounds
AB + CD → AD + CB
- A, B, C, D → reactants represent ions
A & C: positive ions
B & D negative ions
- AD & CB → ionic or molecular compounds
What are the reactants and products of Single Replacement Reactions?
Reactants: element + compound
Product: different element + different compound
What are the reactants and products of double replacement reactions?
Reactants: two compounds
Product: two different compounds
products are typical:
- precipitate or solid
- gas (bubbles)
- water
What is the “Active Series?”
- list elements in reactivity
- SRR: when the replacement element more reactive than the element it tries to replace
What are:
- Beginning Reactions
- Ionic Breakdown
- Balanced Equations
Beginning Reactions:
- positive ions of reactants switch positions to create a product
Ionic Breakdown:
- ions trade places
- combine form neutral compounds
Balanced Equations:
- coefficients used balance overall equation
What are the observable changes in Double Reaction Equations?
- Insoluble Product
- Molecular Product
- Predipitate
Define Aqueous solutions:
the reaction only noticeable when a change is appearance or state occurs
Define Acid-Base Reactions:
Process of neutralization of acid using a base → Acid-Base Reaction or Neutralization Reaction
- double displacement reaction
*
What is a salt, acid-based reaction?
ionic compound formed by reaction of acid and base
Define Acid:
substance is hydrogen ion donor when dissolved in water/reaction
Most acids: H+
Define Base:
- Substance hydrogen acceptor in the reaction
- Produces hydroxide ions when dissolved in water
Most Bases: OH
The reaction 2NO(g) + O2(g) → 2NO2(g) is a synthesis reaction. (2 points)
True or False
True
What is true of synthesis and decomposition reactions? (4 points)
- Synthesis reactions require more energy than decomposition reactions.
- Synthesis reactions produce more products than decomposition reactions.
- Synthesis reactions are the opposite of decomposition reactions.
- Synthesis reactions have fewer reactants than decomposition reactions.
3. Synthesis reactions are the opposite of decomposition reactions.
A synthesis reaction can be identified because it only has pure elements on the left side of the arrow and compounds on the right side of the arrow. (2 points)
True or False
False
Which chemical equation correctly represents the synthesis of calcium sulfite from calcium oxide and sulfur dioxide? (4 points)
- CaSO3(s) → CaO(s) + SO2(g)
- CaSO3(s) + O2(g) → CaO(s) + SO2(g)
- CaO(s) + SO2(g) → CaSO3(s)
- CaO(s) + SO2(g) → CaSO3(s) + O2(g)
3. CaO(s) + SO2(g) → CaSO3(s)