Chem Exam 2

"How many atoms are present in 0.375 mol of palladium (Pd) atoms?

2.26 x 10^23

6. "The top graph shows the mean temperature over the past 160,000 years as determined from ice-core data. Which of graphs A through D best represents the carbon dioxide concentration in air over the same time period as measured from air bubbles trapped in the ice cores?

C, same as original graph or most similar to it

"Although carbon dioxide is the primary compound discussed with respect to global warming; of the common atmospheric components the global warming potential (GWP) of a carbon dioxide molecule is very low. Which statement best explains this pair of facts?

CO2 exists in relatively high concentrations.

"A gasoline's octane rating is determined by:

Comparing its burning properties to those of pure isooctane, which has an octane rating of 100.

"The measure of how much energy is dispersed in a given process is called the:

Entropy

"In order to make useful predictions, which factors must be accounted for by climatic models? I.Aerosol Emissions II.Land Use III.Solar Irradiance

I, II, and III only (aerosol emissions, land use, and solar irradiance). Can also be all 4 if it includes combustion of fossil fuels, and solar irradiance can also be "smoke, haze, and cloud cover"

"Land use changes have a big impact on global warming because of their effect on albedo. Albedo:

Is the ratio of electromagnetic radiation reflected by a surface to the amount of radiation hating that surface.

"What is the effect of infrared energy on matter?

It increases the vibration of chemical bonds.

"Oxygenated gasolines are blends of petroleum-derived compounds with oxygen-containing compounds. Which of the following oxygenated compounds has been discontinued in some states because of potential health risks?

MTBE

"The following molecules contain only single bonds. NH3(g) + 3F2(g) → NF3(g) + 3 HF(g) The bond energies are: N H 391 kJ/mol; F F 158 kJ/mol; N F 272 kJ/mol; H F 566 kJ/mol. Which is the heat evolved or absorbed per mole of NH3 that reacts with F2?

-867 kJ/mol

"Which occurrences or processes are expected to reduce the level of atmospheric carbon? I.Decaying plant and animal remains II.The growth of trees III.Formation of carbonate rock in the ocean IV.Animal respiration

2 and 3, The growth of trees and the formation of carbonate rock in the ocean.

"Octane (C8H18) is one of the principal components of gasoline. How many moles of CO2 are produced during the combustion of 3.0 mol of octane? Unbalanced equation: C8H18 + O2 → CO2 + H2O

24

"Assume that an extremely inefficient electrical utility company delivers electrical energy to your home from a natural gas-burning power plant with an overall efficiency of only 31% and your furnace is 85% efficient in converting electrical energy into heat energy. What mass of natural gas the power plant must burn if heating your home requires 3.5 × 107 kJ? The heat of combustion of natural gas is 50.1 kJ/g.

2650 kg

"Hydrogen gas (H2) is a promising alternative to fossil fuels. How many molecules are present in 1.0 kg of hydrogen gas?

3.0 x 10^23

"Although coal is a complex mixture of substances, its elemental composition can be approximated by the formula C135H96O9NS. Using this formula, predict the amount of CO2 released from the combustion of 1.00 × 106 metric tons of coal (about the annual average for a coal-fired power plant). 1 metric ton = 1 × 103 kg

3.11 x 10^9 kg

"Calculate the amount of energy that is saved by replacing a 75-watt incandescent light bulb with an 18-watt fluorescent bulb during the 1500-hour life of the incandescent bulb. One watt is the equivalent of one joule of energy used per second.

308,000kJ

"The heat of combustion of methane, CH4, is 50.1 kJ/g. How much heat would be generated if 1.00 mol of methane undergoes complete combustion? "

804 kJ

"In which example is the entropy of the initial state lower than the entropy of the final state?

A pot of water boils to produce water vapor at 100 degrees Celsius

"The diagram below shows a simplified version of a fractionating column used in the petroleum industry. The compounds that are obtained at position D are

Asphalt. (Items with the highest boiling points will be at the bottom of the column)

The greenhouse effect refers to the process by which?

Atmospheric gases trap and return infrared radiation radiated by Earth.

"During petroleum refining, catalysts play an extremely important role during the:

Cracking and reforming processes.

"Identify the single most effective strategy to reduce carbon dioxide emissions.

Develop alternate energy sources that do not rely on fossil fuels.

"The first law of thermodynamics states that:

Energy is neither created nor destroyed. Aka conservation of energy

"A gasoline's octane rating is a measure of the:

Gasoline's resistance to causing knocking in a vehicle's engine

"The most abundant greenhouse gas in Earth's atmosphere is:

H2O vapor

"The energy that flows from a warmer body to a colder body is called

Heat

"Consider these three compounds. Which are isomers?

I and III only, the linear one and the bigger of the other 2

"Which substances are regulated by the Kyoto Protocol? I.argon II.carbon dioxide III.nitrogen IV.nitrous oxide V.sulfur hexafluoride

II, IV, and V only- carbon dioxide, nitrous oxide, and sulfur hexafluoride

"Where is most of the carbon on earth stored?

In the form of fossil fuels and carbonate minerals and rocks.

"Which is not a known advantage of natural gas over other fossil fuels?

It is far more abundant than any other fossil fuel.

"Which of the following has the lowest albedo?

Ocean

"Which of the following has the highest boiling point?

Octane

"Tropospheric ozone (O3) is a greenhouse gas. Why is O3 not assigned a Global Warming Potential (GWP)?

Ozone has a relatively short lifetime in the troposphere and its distribution is not uniform around the world.

"Over the very long run, the energy source that has the greatest potential to meet humanity's needs is

Solar (the sun)

"Power plants generate electricity by harnessing the energy stored in chemical bonds. Which lists, in the correct order, the forms that the energy takes to get from a fossil fuel to an electrical outlet?

potential energy -> heat energy -> electrical energy -> mechanical energy

Which of these represent the best Lewis Structure for Acetylene?

the linear one.