Human Anatomy
If the following generic atom were to undergo ionization, what would be the charge of the most likely product?
+2
If the heat of melting of a sample is 135 J/g, what would the heat of freezing for the sample be?
-135 J/g
If a neutral atom gains two electrons, what is the electrical charge of the atom?
-2
How many electrons are used to draw the electron-dot structure for acetylene, a covalent compound with the formula, C2H2
10
Which temperature is the hottest?
100°C
The half-life of carbon-14 is 5,730 years. A sample is found to have one-eighth the original amount of carbon-14 in it. How old is the sample?
17,200 years
Complete the following nuclear equation: 210/84Po → ?? + 4/2He
206/82Pb
Complete the following nuclear equation:?? -> 222/86 Rn +4/2He
226/88Rn
A walnut stuck to a pin is burned beneath a can containing 100.0 grams of water at 21°C. After the walnut has completely burned, the water's final temperature is a warmer 28°C. How much heat energy arose from the burning walnut?
3,000 joules
If a material has a half-life of 24 hours, how long do you have to wait until the amount of radioisotope is 1/4 its original amount?
48 hours
Which of the following is a major advantage of nuclear-fission-based power plants?
A and C
Which of the following is generally true regarding the relationships of the density of an object and its massiveness?
A denser object is not necessarily always more massive.
What is a rem?
A rem is a unit for measuring radiation exposure.
Why do aerosol cans explode if heated?
An increase in temperature will increase the pressure inside the aerosol can. When the pressure inside the can exceeds the pressure limit of the can, it explodes.
Alcohol wiped across a table top rapidly disappears. Which of the following is true?
As the alcohol evaporates it soaks up energy from the table top which is thus cooled.
Barium ions carry a 2+ charge, and nitrogen ions carry a 3-charge. What would be the chemical formula for the ionic compound barium nitride?
Ba3N2
Which of the following molecules has two pairs of nonbonding electrons on the central atom?
C and D
Would it be easier or harder for a water molecule to donate a hydrogen ion if its polar H-O bond were even more polar? Why?
Easier. As polarity increases the bond classification tends towards ionic. An ionic bond would mean a greater separation of positive and negative charge making it easier for the water molecule to donate a hydrogen ion.
Ice floats in room temperature water, but does it float in boiling water? Why or why not?
If boiling water is less dense than ice, the ice cube should sink.
If Earth's oceans were fresh water, would fluctuations in global temperatures be more or less pronounced?
If the oceans were fresh water, the oceans' specific heats would be greater and this would help towards moderating global temperatures.
What happens to the pH of soda water as it loses its carbonation?
It increases as it loses the carbon dioxide molecules which form the carbonic acid in the soda.
What is a half-life?
It is the time it takes for 1/2 of the material to undergo radioactive decay
Why does soap decrease the surface tension of of water?
It keeps water molecules away from the surface.
Why is it better to recycle metals than to mine more?
It takes far less energy to recycle
Which of the following compounds contains ionic bonds?
K2O
Which is more evident: potential or kinetic energy?
Kinetic energy is more evident than potential energy because it involves motion.
You take 50 mL of small BB's and combine them with of large BB's and you get a total of 90 mL of BB's of mixed size. Which of the following statements best explains this?
Many of the smaller BB's are able to fit within the pockets of space that were empty within the of large BB's.
Which of the following molecules contains an ionic bond?
MgCl2
Why does water have a high specific heat?
Much of the added energy is required to break hydrogen bonds.
Water will boil spontaneously in a vacuum. Could you cook an egg in this boiling water?
No, because food is cooked by the transfer of thermal energy from the water to the food, and water at room temperature does not have enough thermal energy to cook an egg.
The age of the Dead Sea Scrolls was found by carbon-14 dating. Could this technique have worked if they were carved in stone tablets? Explain.
No, this method of dating requires a material that was once living.
Which of the following is NOT an ion?
O2
According to the following reaction, which molecule is acting as a base?OH- + NH4+ → H2O + NH3
OH
If water had a lower specific heat, would ponds be more likely to freeze or less likely to freeze?
Ponds would take less time to freeze because they couldn't hold on to heat so well.
Sodium hydroxide is added to a buffer solution of ammonia, NH3, and ammonium chloride, . What is the effect on the concentration of ammonia? What is the effect on the concentration of ammonium chloride?
Sodium hydroxide reacts with only the ammonium chloride, so the concentration of the ammonium chloride decreases and the concentration of ammonia increases.
Your instructor hands you a closed flask of room-temperature water. When you hold it, the heat from your bare hands causes the water to boil. Quite impressive! How is this accomplished?
The air in the flask is very low in pressure, so that the heat from your hand (not the pressure from your hand) will produce boiling at this reduced pressure.
Which of the following statements regarding a phase change is NOT true?
The amount of heat energy stays the same during a phase change
Which has stronger attractions among its submicroscopic particles: a solid at 25°C or a gas at
The attractions among the submicroscopic particles of the solid must be stronger than the attractions among the particles of the gas.
Does the average distance that a neutron travels through fissionable material before escaping increase or decrease when two pieces of fissionable material are assembled into one piece? Does this assembly increase or decrease the probability of an explosion?
The average distance increases while the probability of an explosion also increases.
What happens to the density of a filled water balloon as it is pulled to the bottom of the ocean?
The density of the filled water balloon increases since the balloon is compressed to a smaller volume.
Why does evaporation cool a liquid?
The departing gas molecule takes some kinetic energy with it as it leaves the surface.
What does Einstein's energy equation (E = mc2) say about the energy that is derived from nuclear fission reactions?
The energy released is due to the missing mass of the products compared to the mass of the starting materials
The number of nonbonding pairs in the water molecule is ________.
The number of nonbonding pairs in the water molecule is ________.
According to Gay-Lussac's law, what happens to a gas as temperature increases?
The pressure increases.
Why do ice skates work?
The pressure of the blades on the ice creates a temporary water layer.
Why might the following nuclear reaction not be very good for energy production in a fission reactor? 235/92U → 229/90Th + 4/2He + 3 neutrons
The products are not the right size to obtain much energy from missing mass due to strong nuclear force.
What best describes what happens when an acid such as HCl is mixed with water?
The proton chemically bonded to the chlorine is transferred to a water molecule and forms a chloride ion and a hydronium ion.
How can a half-life be used to tell the age of a sample?
The ratio between the radioactive form and stable form varies regularly with time.
Why might the following nuclear reaction not be very good for energy production in a fission reactor 56/26Fe →29/14 Si + 24/12Mg + 3 neutrons
The reactants are too small to obtain energy from the missing mass due to strong nuclear force.
What happens if you were to place a concentrated solution into a bag made of a semipermeable membrane and were to then suspend it in a very dilute solution?
The size of the suspended bag would increase.
Which has more total energy: a cup of boiling water at 100°C or a swimming pool of slightly cooler water at 90°C?
The swimming pool at 90°C has more energy.
The amphoteric reaction between two water molecules is endothermic, which means that this reaction requires the input of energy in order to proceed: Energy + H2O + H2O → H3O+ + OH- The warmer the temperature of the water, the more thermal energy is available for this reaction, and the more hydronium and hydroxide ions are formed. Based on this information, should the value of Kw be expected to increase, decrease, or stay the same with increasing temperature?
The value of Kw will increase since the rise in temperature allows for a higher concentration of both ions.
What physical quantities discussed in this chapter change most when a junked car is neatly crushed into a compact cube?
The volume of the car changes as well as its average density.
Place a card over the open top of a glass filled to the brim with water, and then invert it, as is shown below. Why does the card stay in place? How about when the glass is held sideways?
The weight of the air pushing against the outer surface of the card is much greater than the weight of the water pushing against the inner surface of the card, whether inverted or held sideways.
The valence electron of a sodium atom does not sense the full +11 of the sodium nucleus. Why not?
There are two inner shells of electrons containing ten electrons shielding the sodium nucleus from sensing it.
Which of the following solutions is the most dilute?
They all have the same concentration
Atoms of metallic elements can form ionic bonds, but they are not very good at forming covalent bonds. Why?
They have a great tendency to lose electrons.
A great deal of heat is released when liquid water freezes. Why doesn't this heat simply remelt the ice?
This heat is radiated outwards to the environment, rather than back into the ice
A great deal of heat is released when liquid water freezes. Why doesn't this heat simply remelt the ice?
This heat is radiated outwards to the environment, rather than back into the ice.
Hard water contains excessive amounts of ________.
Two of the above are the most appropriate answers.
Why doesn't uranium ore spontaneously undergo a chain reaction?
Uranium ore is mostly non-fissionable isotope U-238.
Suppose that water is used in a thermometer instead of mercury. If the temperature is at 4°C and then changes, why can't the thermometer indicate whether the temperature is rising or falling?
Water is most dense at 4°C. The water in a water-filled thermometer at 4°C would expand as the water was cooled or heated.
Why are drops of water shaped like spheres?
Water molecules at the surface are pulled into the liquid, making the drop as small as possible.
Why does water not freeze at 0°C when either ions or molecules other than H2O are present?
When molecules or ions are dissolved in the water, these solute molecules both take up space and inhibit the formation of the solid phase, thus lowering the freezing point temperature below 0°C
From the diagram above describing the phase of water relative to temperature and pressure, is it possible for ice to transform to water vapor (sublime) without ever becoming liquid? At which point on the diagram does this occur?
Yes, water can be made to sublime. This occurs at point D on the diagram.
Can an acid and a base react to form an acid?
Yes. An acid and a base can react to form an acid if the acid is a strong acid and the base is a weak base.
The image below shows a beam of radiation passing between two electrically charged plates. Which of the beams is actually composed of charged particles?
a and c
If three samples have the half-lives listed below, which sample would remain radioactive the longest?
a sample with a half-life of 20 million years
What is the mass in kilograms of a human weighing 130-pounds on the moon?
about 350 kg
The scanning probe microscope creates images of atoms by ________.
all of the above
Which of the following is an example of something with potential energy?
all of the above
Which of the following statements regarding a nucleon is true?
all of the above
Why does adding heat to ice-water disfavor the rate of ice formation?
all the above
Condensation is ________.
always a warming process
According to John Dalton, atoms of a given element ________.
are identical
The image below shows a beam of radiation passing between two electrically charged plates. Which of the beams is due to an energetic non-visible light wave?
b
How come an animal's carbon-14 levels do not start to decrease until it dies?
because it constantly replenishes its carbon-14 supply by eating plants with carbon-14 in them
What is the molecular shape of the following molecule?
bent
What is transmutation?
changing one element into another by adding or removing protons from the nucleus
If the rate at which we produce CO2 were to stop rising, the levels of CO2 in the atmosphere would ________.
continue to rise
If all of the capillaries pictured above were the same size diameter, which would contain the liquid with the greatest capillary action?
d
Which of the following is not a property of metal?
does not conduct heat well
Which of the above liquids has the strongest cohesive forces?
e
Which of the above liquids would most likely have the least capillary action?
e
Which of the following is the correct electron dot structure for carbon (atomic no. = 6)?
e (four dots)
Heat is absorbed by a substance when that substance ________.
evaporates
An old remedy for separating a pair of nested drinking glasses stuck together is to run water at one temperature into the inner glass and then run water at a different temperature over the surface of the outer glass. Which water should be hot and which should be cold?
fill the inner glass with cold water while running hot water over the outer glass
Heat is given off by a substance when that substance ________.
freezes
Which graph most appropriately shows the density of water plotted against temperature?
graph b
A hydrogen atom does not form more than one covalent bond because it ________.
has only one electron to share
Is the density of near-freezing water, which contains microscopic ice crystals, greater or less than the density of liquid water containing no microscopic ice crystals?
less dense
A biological cell is best described as ________.
microscopic
Which of the following nuclear equations correctly describes alpha emission?
none of the above
What is the molecular shape of the following molecule?
pyramidal
In the following buffer system, what happens to the concentration of the highlighted molecule if you add base in the form of OH-?HF + NaF + H2O F- + H3O+ + Na+
stays about the same
Ice is slippery because ________.
surface crystals fall apart
Along with the pH scale, there is the pOH scale, which indicates the level of "basicity" in a solution. Accordingly, pOH = -log[OH-]. What is the sum of the pH and the pOH of a solution always equal to?
the negative log of Kw, which is 14
In behaving as both an acid and a base, water reacts with itself to form ________.
two of the above.