Which of the following best helps to explain why hexane has a higher boiling point than methanol has?   The figure shows a three column table with four rows of data. The heading for column 1 is “Compound.” The heading for column 2 is “Structure.” The heading for column 3 is “Boiling Point, in degrees Celsius.” The data in the table are as follows. Row 1. Compound: Methanol. Structure: A C atom is connected to 3 H atoms and 1 O atom, each by a single bond. The O atom has two pairs of nonbonding electrons. The O atom is connected to an H atom by a single bond. Boiling Point: 65 degrees Celsius. Row 2. Compound: Ethanol. Structure: 1 C atom is connected to 3 H atoms and 1 C atom, each by a single bond. The second C atom is connected to 2 H atoms and 1 O atom, each by a single bond. The O atom has two pairs of nonbonding electrons. The O atom is connected to 1 H atom by a single bond. Boiling Point: 78 degrees Celsius. Row 3. Compound: Propanal. Structure: 1 C atom is connected to 3 H atoms and 1 C atom, each by a single bond. The second C atom is connected to 2 H atoms and 1 additional C atom, each by a single bond. The C atom is connected to 1 O atom by a double bond and 1 H atom by a single bond. The O atom has two pairs of nonbonding electrons. Boiling Point: 49 degrees Celsius. Row 4. Compound: Hexane. Structure: 6 C atoms are arranged in a horizontal row, each connected by a single bond. The leftmost and rightmost C atoms are each connected to 3 H atoms by single bonds. The middle 4 C atoms are each connected to 2 H atoms by single bonds. Boiling Point: 69 degrees Celsius.

When free Cl(g) atoms encounter O3(g) molecules in the upper atmosphere, the following reaction mechanism is proposed to occur.   Cl(g) + O3(g) → ClO(g) + O2(g) slow step   ClO(g) + O3(g) → Cl(g) + 2 O2(g) fast step   2 O3(g) → 3 O2(g)  overall reaction △H = -285 kJ/molrxn     X + O3 → XO + O2 XO + O3 → X + 2 O2 2 O3 → 3 O2   The proposed mechanism can be written in a more general form, as shown above. Species other than Cl can also decompose O3 through the same mechanism. Which of the following chemical species is most likely to decompose O3 in the upper atmosphere through the mechanism in the above mechanism?

The graph shows the heating curve for methane, CH4.   The figure shows a graph with the horizontal axis labeled Heat Added and the vertical axis labeled Temperature, in units of Kelvin. The numbers appearing on the vertical axis, from bottom to top, are from zero to 150, in increments of 10. A line begins at 60 Kelvin on the vertical axis and moves up and to the right until 90 Kelvin; this portion of the line is labeled P. The line then moves horizontally to the right for a very short distance; this portion of the line is labeled Q and contains the text, delta H subscript fusion equals zero point nine four kilojoules per mole. The line then moves up and to the right until 110 Kelvin; this portion of the line is labeled R. The line then moves horizontally to the right this portion of the line is labeled S and contains the text, delta H subscript vaporization equals 8 point 2 kilojoules per mole. The line then moves up and to the right ending at 140 Kelvin; this portion of the line is labeled T. The enthalpy of vaporization of water is 40.7 kJ/mol. Which of the following best explains why the enthalpy of vaporization of methane is less than that of water?

Which of the following Lewis electron-dot diagrams represents the molecule that is the most polar?

An experiment is performed to measure the mass percent of CaCO3(s) in eggshells. Five different samples of CaCO3(s) of known mass react with an excess of 2.0 M HCl(aq) in identical sealed, rigid reaction vessels. The pressure of the gas produced is measured with a pressure gauge attached to the reaction vessel. Since the reaction is exothermic, the reaction system is cooled to its original temperature before the pressure is recorded. The experimental data are used to create the calibration line below.   The figure presents a graph consisting of five points and a straight line of best fit. The horizontal axis is labeled “Mass of C a C O 3, solid, in grams,” and the numbers 0.05 through 0.20, in increments of 0.05, are indicated. The vertical axis is labeled “Pressure of Gas Produced, in atmospheres,” and the numbers 0.02 through 0.10, in increments of 0.01, are indicated. The data represented in the graph are as follows. Note that all values are approximate. The line begins at a mass of 0.06 gram and a pressure of 0.03 atmosphere, and ends at a mass of 0.21 gram and a pressure of 0.10 atmosphere. The data points are at 0.07 gram and 0.032 atmosphere; 0.09 gram and 0.045 atmosphere; 0.14 gram and 0.068 atmosphere; 0.17 gram and 0.08 atmosphere; and 0.20 gram and 0.096 atmosphere.   The experiment is repeated with an eggshell sample, and the experimental data are recorded in the table below.   Mass of eggshell sample 0.200 g Pressure prior to reaction 0.800 atm Pressure at completion of reaction 0.870 atm   The mass percent of CaCO3(s) in the eggshell sample is closest to

The melting point of MgO is higher than that of NaF. Explanations for this observation include which of the following? I. Mg2+ is more positively charged than Na+.II. O2- is more negatively charged than F-.III. The O2- ion is smaller than the F- ion.

When Reaction 3 occurs, does the hybridization of the carbon atoms change? Reaction 1: CaC2(s) + 2 H2O(l) → C2H2(g) + Ca(OH)2(s)Reaction 2: NaOCl(aq) + 2 HCl(aq) → Cl2(g) + NaCl(aq) + H2O(l)Reaction 3: C2H2(g) + Cl2(g) → C2H2Cl2(g)

Which species has a trigonal-pyramidal molecular geometry?

Which of the following best represents the ground-state electron configuration for an atom of selenium?

Which of the following lists the substances F2, HCl, and HF in order of increasing boiling point?