Reaction Chemistry (10%) Flashcards
Which of the following elements does not have a noble gas configuration?
(A) Na (sodium) (B) He (helium) (C) Ar (argon) (D) Ne (neon) (E) they are all noble gases
(A) Na (Sodium)
The atomic masses of carbon and oxygen are 12 and 16, respectively. What is the approximate percent by mass of oxygen in carbon dioxide, CO2?
(A) 25% (B) 50% (C) 66% (D) 75% (E) 85%
(D) 75%
12 (C) + 16 (O) + 16 (O) = 44
32 (O2) / 44 = 0.73 (73%) - Closest answer.
Within molecules of a compound, atoms are held together by chemical bonds that are primarily
(A) thermal (B) frictional (C) gravitational (D) electrostatic (E) magnetic
(D) electrostatic
CaO+CO2→CaCO3
What mass of CaO is needed to absorb 22 grams of CO2 according to the balanced chemical equation above? (Molar masses: CaO=56g/mol, CO2=44g/mol
)
(A) 112 g (B) 100 g (C) 56 g (D) 28 g (E) 22 g
(D) 28 g
How to solve:
56 44
—- —-
x 22
2NO2(g)→←N2O4(g)
The equation above represents a system that has reached a state of chemical equilibrium. Which of the following is a true statement about the system?
(A) All chemical reaction rates have dropped to zero.
(B) The system will eventually contain only N2O4 molecules.
(C) The concentration of NO2(g) must be twice that of N2O4(g).
(D) The concentration of NO2(g) must be less than that of N2O4(g).
(E) N2O4 molecules are being consumed as fast as they are produced.
(E) N2O4 molecules are being consumed as fast as they are produced.
The following reaction is an example of which type of reaction?
2NaN3(s)→3N2(g)+2Na(s)
(A) combination (B) replacement (C) decomposition (D) double displacement (E) none of the above
(C) decomposition
In old-fashioned flashbulbs, light was produced by the reaction of magnesium metal, Mg, sealed in the bulb with oxygen gas, O2. After the flash, the mass of the sealed bulb was
(A) definitely greater than it was before use
(B) definitely smaller than it was before use
(C) essentially the same as it was before use
(D) greater or smaller depending on the amount of O2
consumed
(E) greater or smaller depending on the amount of light produced
(C) essentially the same as it was before use
Which term best describes the bonds between Hydrogen and Oxygen in a molecule of water?
(A) salt (B) strong (C) ionic (D) covalent (E) non-polar
(D) covalent
Reason: The formation of water molecules provides an example of covalent bonding. The hydrogen and oxygen atoms that combine to form water molecules are bound together by covalent bonds. The electron from the hydrogen splits its time between the incomplete outer shell of the hydrogen atoms and the incomplete outer shell of the oxygen atoms. To completely fill the outer shell of oxygen, which has six electrons in its outer shell but which would be more stable with eight, two electrons (one from each hydrogen atom) are needed: hence the well-known formula H2O. The electrons are shared between the two elements to fill the outer shell of each, making both elements more stable.
Which of the following are the four elements that are the basis of organic chemistry?
(A) H, O, P, S (B) C, H, O, N (C) B, C, N, O (D) Na, K, Mg, Ca (E) C, H O, F
(B) C, H, O, N
A _____ is two or more atoms held together by shared electrons – like H2.
(A) Molecule
(B) Compound
(C) Covalent
(D) Ionic
(A) Molecule
A _____ is two or more different elemental atoms bond together through the sharing of electrons – like water!
(A) Molecule
(B) Compound
(C) Covalent
(D) Ionic
(B) Compound
Atoms will exchange or share electrons in order to fill the valence shell. This is called
(A) Covalent
(B) Ionic
(C) Chemical bonding
(D) Valence shell electrons
(C) Chemical bonding
There are two common modes of bonding: _____, where a pair of electrons is SHARED. _____ where electrons are EXCHANGED.
(A) Ionic, Covalent
(B) Covalent, Ionic
(C) Molecular, Compound
(D) Compound, Molecular
(B) Covalent, Ionic
H20 (Water) has _____ valence shell electrons. The magic number!
(A) 2
(B) 4
(C) 6
(D) 8
(D) 8
When a molecule is presented in a stick configuration (H-0-2), the “sticks” represent
(A) Electrons being shared
(B) Electrons being exchanged
(C) Protons being shared
(D) Protons being exchanged
(A) Electrons being shared
In _____, one atom loses an electron and another takes it.
(A) Covalent bonding
(B) Ionic bonding
(C) Chemical bonding
(D) None of the above
(B) Ionic bonding
In ionic bonding, the atom that loses an electron has a (+) charge, and is called a
(A) Anion
(B) Cation
(C) Ion
(B) Cation
In ionic bonding, the atom that gaines an electron has a (-) charge, and is called a
(A) Anion
(B) Cation
(C) Ion
(A) Anion
Chemical reactions occur when molecules or atoms interact with each other. Reactions are symbolized with an arrow showing reaction progress from _____ to _____.
(A) Products to reactants
(B) Reactants to products
(B) Reactants to products
In this chemical reaction type, the reaction often starts with a single reactant that degrades into multiple products:
AB → A + B
(A) Decomposition
(B) Combination
(C) Replacement
(D) Double displacement
(A) Decomposition
In this chemical reaction type, the reaction often starts with multiple reactants that react to form a single product:
A + B → AB
(A) Decomposition
(B) Combination
(C) Replacement
(D) Double displacement
(B) Combination
In this chemical reaction type, one compound breaks apart and forms a new compound with a different reactant:
AB + C → AC + B
(A) Decomposition
(B) Combination
(C) Replacement
(D) Double displacement
(C) Replacement
In this chemical reaction type, two compounds break apart and exchange components to form new compounds:
AB + CD → AC + BD
(A) Decomposition
(B) Combination
(C) Replacement
(D) Double displacement
(D) Double displacement
A chemical reaction can also be categorized as an oxidation or a reduction. (Remember LEO GER). Element that loses electrons = _____.
(A) Oxidation
(B) Reduction
(A) Oxidation
A chemical reaction can also be categorized as an oxidation or a reduction. (Remember LEO GER). Element that gains electrons = _____.
(A) Oxidation
(B) Reduction
(B) Reduction
Chemical reactions are either
(A) Exothermic (B) Thermic (C) Endothermic (D) A and C (E) B and C
(D) A and C (Exothermic and Endothermic)
This type of chemical reaction releases energy.
(A) Exothermic
(B) Endothermic
(A) Exothermic
This type of chemical reaction requires an input of energy to proceed.
(A) Exothermic
(B) Endothermic
(B) Endothermic
All reactions must follow the laws of
(A) Exothermic
(B) Endothermic
(C) Thermodynamics
(C) Thermodynamics
In the laws of thermodynamics, matter and energy can be created and destroyed.
(A) True
(B) False
(B) False
- The law of conservation of energy and matter – matter and energy can be neither created or destroyed.
Energy and matter must always be balanced.
In the laws of thermodynamics, all reactions spread energy, which will tend to diminish its availability.
(A) True
(B) False
(A) True
- The law of increasing disorder (entropy) – all reactions spread energy, which will tend to diminish its availability.
Reactions progress to degrade potential energy.
_____ has a number of properties that make it a unique substance:
- It is polar
- It expands when frozen (solid phase is less dense than liquid phase)
- High specific heat
- High surface tension
(A) Gas
(B) Water
(C) Metal
(D) Vapor
(B) Water
Water’s hydrogen bonding interactions lead to
(A) Low surface tension
(B) High surface tension
(C) Low pressure
(D) High pressure
(B) High surface tension
In organic chemistry, _____ is really important because the skeleton of the organic compound is often built up almost entirely of this.
(A) Carbon
(B) Hydrogen
(C) Oxygen
(D) Nitrogen
(A) Carbon
