Chem practice exam
Of the bonds below, ________ is the least polar.
N-O
Which of the following correctly lists the five atoms in order of increasing size (smallest to largest)?
Ne < O < S < Si < Ge
For the combustion reaction of methane, ΔH°f is zero for ________. CH4 (g) + O2 (g) → 2H2O(g) + CO2 (g)
O2 (g)
Which combination will produce a precipitate?
Pb(NO3)2 (aq) and HCl (aq)
Which element forms an ion with the same charge as the carbonate ion?
Sulfur
Which of the following statements is false?
The change in entropy in a system depends on the initial and final states of the system and the path taken from one state to the other.
The ground-state electron configuration for Zn is ________.
[Ar]4s23d10
Of the possible bonds between carbon atoms (single, double, and triple), ________.
a double bond is longer than a triple bond
If matter is uniform throughout and cannot be separated into other substances by physical processes, but can be decomposed into other substances by chemical processes, it is called a(n)
compound
The Lewis structure of N2H2 shows ________.
each nitrogen has one nonbonding electron pair
In the Bohr model of the atom, ________.
electron energies are quantized
The reaction 4Al (s) + 3O2 (g) → 2 Al2O3 (s) ΔH° = -3351 kJ is ________, and therefore heat is ________ by the reaction.
exothermic, released
Reduction is the ________ and oxidation is the ________.
gain of electrons, loss of electrons
A weak electrolyte exists predominantly as ________ in solution.
molecules
Given the following table of thermodynamic data, TiCl4 (g) -763.2 354.9 TiCl4 (l) -804.2. 221.9 complete the following sentence. The vaporization of TiCl4 is ________.
nonspontaneous at low temperature and spontaneous at high temperature
When work is done on a system, w will be a ________ value.
positive
For the reaction 2 C4H10 (g) + 13 O2 (g) → 8 CO2 (g) + 10 H2O (g) ΔH° is -125 kJ/mol and ΔS° is +253 J/K ∙ mol. This reaction is ________.
spontaneous at all temperature
The molecular geometry of the BrF5 molecule is ________, and this molecule is ________.
squarer pyramidal, polar
Using the VSEPR model, the electron-domain geometry of the central atom in AsF3 is ________.
tetrahedral
Cathode rays are deflected away from a negatively charged plate because ________.
they are negatively charged particles
Consider the following selected postulates of Dalton's atomic theory: (i) Each element is composed of extremely small particles called atoms. (ii) Atoms are indivisible. (iii) Atoms of a given element are identical. (iv) Atoms of different elements are different and have different properties. Which of the postulates is(are) no longer considered valid?
(ii) and (iii)
The combustion of titanium with oxygen produces titanium dioxide: Ti (s) + O2(g) → TiO2 (s) When 0.610 g of titanium is combusted in a bomb calorimeter, the temperature of the calorimeter increases from 25.00 °C to 50.50 °C. In a separate experiment, the heat capacity of the calorimeter is measured to be 9.84 kJ/oC. The heat of reaction for the combustion of a mole of Ti in this calorimeter is ________ kJ/mol.
-1.98 X 10^4
Given the following reactions N2 (g) + O2 (g) → 2NO (g) ΔH = +180.7 kJ 2N2O (g) → O2 (g) + 2N2 (g) ΔH = -163.2 kJ the enthalpy of reaction for 2N2O (g) → 2NO (g) + N2 (g)
17.5
Balance the following reaction and determine the coefficient of nitric acid. N2O5 (g) + H2O (l) → HNO3 (aq)
2
How many unhybridized p atomic orbital(s) are found in an sp-hybridized carbon atom?
2
There are ________ significant figures in the answer to the following computation: ((29.2-20.0)(1.79*10^5))/1.39
2
The combustion of propane (C3H8) produces CO2 and H2O: C3H8 (g) + O2 (g) → CO2 (g) + H2O (g) (not balanced) The reaction of 2.5 mol of O2 with 4.6 mol of C3H8 will produce ________ mol of H2O.
2.0
Which of the following reactions would have a negative ΔS?
2SO2 (g) + O2 (g) → 2SO3 (g)
Which one of the following represents an acceptable set of quantum numbers for an electron in an atom? (arranged as n, l, ml, and ms)
3, 0, 0, -1/2
A 4.50-g sample of liquid water at 25.0 °C is heated by the addition of 133 J of energy. The final temperature of the water is ________ °C. The specific heat capacity of liquid water is 4.18 J/g-oC.
32.1
The ion ICl4- has ________ valence electrons.
36
What volume (mL) of 0.201 M potassium hydroxide will it take to reach the equivalence point in a 16.3 mL aliquot of 0.226 M triprotic acid?
55.0
How many grams of H3PO4 are in 175 mL of a 4.00 M solution of H3PO4?
68.6
Lead (II) carbonate decomposes to give lead (II) oxide and carbon dioxide: PbCO3 (s) → PbO (s) + CO2 (g) ________ grams of lead (II) oxide will be produced by the decomposition of 8.75 g of lead (II) carbonate?
7.31
If an electron has a principal quantum number (n) of 7 and an angular momentum quantum number (l) of 3, the subshell designation is ________.
7f
The number with the most significant zeros is ________.
90.300
There are ________ protons, ________ neutrons, and ________ electrons in 238U+5.
92, 146, 87
Based on the octet rule, aluminum most likely forms an ________ ion.
Al3+
Which of the following elements is a nonmetal?
At
A 22.5-g sample of ammonium carbonate contains ________ mol of ammonium ions.
0.467
A stock solution of HNO3 is prepared and found to contain 12.7 M of HNO3. If 25.0 mL of the stock solution is diluted to a final volume of 0.500 L, the concentration of the diluted solution is ________ M.
0.635
Which one of the following has the element name and symbol correctly matched?
Be, beryllium
The spectator ions in the reaction between aqueous hydrobromic acid and aqueous sodium hydroxide are ________.
Br- and Na+
In which species does bromine have an oxidation number of zero?
Br2
A compound that is composed of only carbon and hydrogen contains 85.7% C and 14.3% H by mass. What is the empirical formula of the compound?
CH2
Of the following atoms, which has the largest first ionization energy?
Ca
When calcium reacts with sulfur the compound formed is ________.
CaS
Element M reacts with fluorine to form an ionic compound with the formula MF3. The M-ion has 21 electrons. Element M is ________.
Cr