Practice Midterm Exam Flashcards
Which of the following describes a scientific law?
A scientific law is a concise statement that summarizes a fundamental relationship of nature.
Which of the following statements is not a part of Dalton’s atomic theory.
The number of protons determines the identity of an atom
Which of the following elements of the scientific method is a concise summary of repeated scientific observations?
A scientific law.
An intensive property such as density is only relevant to pure substances and homogeneous mixtures, and not to heterogeneous mixtures.
false
“Melting point” is not a(n) _____________________.
qualitative property of a substance
Which of the following particles have roughly the same mass?
a proton and a neutron
Lithium combines with fluorine in a 1:1 ratio. Which of the following pairs of elements also combines in a 1:1 ratio?
potassium (K) and bromine (Br)
What is the coefficient for water in the properly balanced equation for the combustion of butane and oxygen gas to form carbon dioxide gas and water according to the equation:
C4H10 + O2 → CO2 + H2O
10
What is the mass of the oxygen in 2.0 moles of silver nitrate (AgNO3)?
96 grams
A reaction has an expected yield of 30.5 grams. What is the percent yield if performing the reaction produced 29.6 grams of product?
97.0 percent
The following reaction is of which type?
2KClO3(s) -> 2KCl(s) + 3O2
oxidation-reduction reaction
In an oxidation-reduction reaction, it required 25.6 ml of a 0.65 M potassium permanganate solution to reach the equivalence point with 15.0 mL of an iron(II) sulfate solution. What is the molar concentration of the iron(II) sulfate solution? The net ionic equation for the reaction is:
MnO4-(aq) + 5Fe2+(aq) + 8H+(aq) -> Mn2+(aq) + 5Fe3+(aq) + 4H2O(l)
5.6 M
A balloon containing 4.28 L of an unknown gas at 1.00 atm and 298 K has a mass of 16.90 g. The empty balloon has a mass of 2.24 g. What is the molar mass of the gas in the balloon?
83.8 g/mol
The larger the volume of the individual molecules of a gas, the more that gas behaves like an ideal gas.
false
Which of the following correctly represents an exothermic reaction?
ΔH < 0
What is the primary difference between coffee-cup calorimetry and bomb calorimetry?
Coffee-cup calorimetry is carried out at constant pressure and bomb calorimetry is carried out at constant volume.
In the visible absorption spectrum of a gas sample, certain discrete frequencies are missing. What do these missing frequencies represent?
Frequencies which cause the electrons of the gas to move to higher energy levels
Both the d orbitals and the f orbitals have exactly three angular nodes.
false
The principal quantum number is not a good indicator of orbital energy level because:
of electron shielding
Alkali metals are
strong reducing agents