Chemistry Chemical Formulas and Reactions
Calcium carbonate was placed in a flask on a balance, and dilute hydrochloric acid was added. Carbon dioxide that was produced escaped from the flask. The total mass of the flask and its contents was recorded every 10 seconds. The diagram above shows a plot of the results. Between which of the following times was the reaction the fastest?
0 and 10 seconds
Hydrogen chloride can be formed from hydrogen and chlorine as shown in the reaction. H2 + Cl2 → 2HCl + heat Chlorine and fluorine are located in the same group in the periodic table. If the reaction were performed with fluorine instead of chlorine, how many moles of H2 would be required to balance the equation?
1
The figure above shows a compound containing hydrogen (H) and an unknown element Z. To which group on the periodic table does element Z belong?
15
According to the periodic table, Mg will most likely react with elements in which of these groups?
17
The diagram above is a potential energy curve for a reaction. Which number represents the effect of a catalyst on the reaction?
2
__P + __Br2 → __PBr3 Which set of coefficients will balance this equation?
2, 3, 2
Which set of coefficients will balance this equation? __Al + __HCl →__AlCl3 + __H2
2, 6, 2, 3
Ni(C2H3O2)4 How many atoms are represented in this formula?
29
Which of the following reactions is an example of a single-replacement reaction?
2AgNO3 + Cu → Cu(NO3)2 + 2Ag
Aluminum + Sulfuric Acid → Aluminum Sulfate + Hydrogen Gas Which of the following is the balanced chemical equation for the reaction shown above?
2Al + 3H2SO4 → Al2(SO4)3 + 3H2
iron (III) chloride + sodium carbonate → iron (III) carbonate + sodium chloride Which of these is the balanced equation for the reaction described above?
2FeCl3 + 3Na2CO3 → Fe2(CO3)3 + 6NaCl
Which of the following reactions is a decomposition reaction?
2KClO3 → 2KCl + 3O2
Which of these reactions shows simple chemical decomposition?
2NaCl → 2Na + Cl2
How many different elements are in ammonium hydroxide (NH4OH)?
3
__AgNO3 + __AlCl3 → __AgCl + __Al(NO3)3 Which of these sets of coefficients will balance this equation?
3, 1, 3, 1
3MgO + 2Al → ? What would be the product(s) of this reaction?
3Mg + Al2O3
What is the correct Lewis dot structure for arsenic?
5 dots
In the above reaction, a cloudiness at completion due to colloidal suspension of sulfur appears. If the reaction is carried out at various temperatures, at which temperature would it proceed at the fastest rate?
50°C
Which of these is the general formula for a double-replacement reaction?
AB + XY → AY + XB
The formula H2SO4 is representative of which of the following?
An acid
Each beaker shown above contains 2.2 grams of iron and 1 liter of 3M H2SO4 at STP. Which reaction will go to completion first and why?
Beaker B because of increased surface area
Catalytic converters made of palladium (Pd) reduce automobile pollution by catalyzing the reaction between unburned hydrocarbons and oxygen. How does Pd increase the rate of this reaction?
By decreasing the activation energy
Which is an example of a synthesis reaction?
C + O2 → CO2
A compound is composed of 85.64% carbon and 14.36% hydrogen. The compound has a formula mass of 42.08 grams. What is the molecular formula?
C3H6
Which of the following is a balanced equation?
C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(g)
What is the molecular formula of a substance that has an empirical formula of C2H5 and a molecular mass of 58 g/mole?
C4H10
A compound is composed of 58.8% C, 9.8% H, and 31.4% O, and the molar mass is 102 g/mol. What is the molecular formula for this compound?
C5 H10 O2
Which of these represents the empirical formula and the molecular formula, respectively, for a given organic compound?
CH and C2H2
The diagram shows the structural formula of benzene. The empirical and the molecular formulas of benzene are, respectively -
CH, C6H6
The empirical formula for C6H12 is -
CH2
Cobalt, a transition metal, can have an oxidation number of either 2+ or 3+. Which of these represents the two possible chemical formulas for the chemical combination of cobalt with oxygen?
CoO, Co2O3
Using the chart above, which of these combinations will probably form a precipitate?
Copper (II) carbonate
What type of reaction does this illustration represent?
Decomposition
Which type of reaction is represented here? Na2CO3 + Ca(OH)2 → 2NaOH + CaCO3
Double replacement
Which of the following containers of water best shows dynamic equilibrium between vapor and liquid?
F
Which is the correct formula for iron (III) sulfate?
Fe2(SO4)3
What is the chemical formula for iron(II) phosphide?
Fe3P2
Which of the following equations is balanced?
H2O + MgO → Mg(OH)2
Which of the following best represents the reaction between sulfuric acid and calcium hydroxide?
H2SO4 + Ca(OH)2 → CaSO4 + 2H2O
Which of the groups below has the electron dot structure shown above?
Halogens
Very Active Metal + Water → Metal Hydroxide + ? Which of these completes this reaction?
Hydrogen
Sodium iodide exhibits what type of bond?
Ionic
According to the table, which of these probably has the strongest bonds?
Iron crystals
What is the name for FeCl3 using the IUPAC nomenclature rules?
Iron(III) chloride
The correct structural formula for C2H4 is -
J
Which of the following reactions is a neutralization reaction?
KOH + HNO3 → KNO3 + H2O
The formula for lithium nitride is -
Li3N
Which statement describes the above equation?
Magnesium transfers an electron to each atom of the iodine molecule.
The formula for magnesium chloride is -
MgCl2
Which of these represents a synthesis reaction?
N2 + 3H2 → 2NH3
The formula for dinitrogen tetroxide is -
N2O4
Which compound contains both ionic and covalent bonds?
NH4Cl
Which compound has a covalent bond?
NO
Chlorine and bromine are in the same family in the periodic table. According to the information in the table above, what would be the correct formula for sodium bromate?
NaBrO3
Which completes the chemical equation above?
O2
Which of these is the correct name for KBr?
Potassium bromide
When naming a transition metal that has more than one oxidation number, the numeric value of the oxidation number is indicated by a -
Roman numeral
A compound has 50% sulfur and 50% oxygen. What is its empirical formula?
SO2
Zn + CuSO4 → Cu + ZnSO4 Which reaction type best describes the reaction above?
Single replacement
When an electric current is passed through water, the reaction shown takes place. If the arrow were pointing in the opposite direction, what type of reaction would the new reaction represent?
Synthesis
Which of the following is the correct molecular shape of CH4?
Tetrahedral
What shape does the molecule BF3 have?
Trigonal planar
The coefficients necessary to balance the equation correctly are -
a=1,b=2,c=1,d=2
A catalyst accelerates a chemical reaction because the -
activation energy of the reaction is lowered in the presence of a catalyst
The name for NH4F is -
ammonium fluoride
The correct name for the compound CCl4 is -
carbon tetrachloride
O2, N2, Cl2, and I2 are examples of -
diatomic molecules
The correct name for P2O5 is -
diphosphorus pentoxide
This diagram of a chemical reaction shows that the reaction is -
endothermic
If the difference in electronegativity between atoms of different non-metals is small, the atoms of the two non-metals will most likely -
form a covalent bond
If the temperature of a reaction is increased, the reaction proceeds at a much quicker rate because the -
frequency of collisions between reactants increases
A catalyst is a substance used in chemical reactions to -
increase the rate of the reaction
The type of bond found in magnesium chloride is -
ionic
A Lewis dot diagran of a nitrogen molecule. According to the Lewis diagram, a nitrogen molecule has a -
linear structure and a triple bond
The correct name for MgI2 is -
magnesium iodide
The correct name for Mg3(PO4)2 is -
magnesium phosphate
If the above diagram were the correct representation for the Lewis structure of a molecule, then the X would be representative of the element -
nitrogen
The Lewis electron dot system represents electrons in the -
outer energy level
In chemical compounds, covalent bonds form when -
pairs of electrons are shared between two nonmetal atoms
Fe + CuCl2 → FeCl2 + Cu The type of reaction represented by the above equation is -
single-replacement
The type of formula that shows the arrangements of atoms and bonds is called -
structural
To indicate the number of atoms of each element present in a molecular compound, scientists use -
subscripts
When seltzer tablets are placed in a glass of water, they fizz as they release a gas. To increase the speed that the gas is released from each tablet, it would be best to increase the
temperature of the water
A heated liquid placed in a closed container will vaporize until -
the number of liquid molecules vaporizing equals the number of vapor molecules condensing
The system that shows a decrease in entropy (disorder) is -
water freezing
