Unit 3 Homework

An electron is pushed into an electric field where it acquires a 1-Volt electrical potential. If two electrons are pushed the same distance into the same electric field, the electrical potential of the two electrons is 2 Volts 4 Vlolts 0.5 Volts 0.25 Volts 1 Volt

1 Volt

When a pair of 1 ohm resistors are connected in series, their combined resistance is 2 ohms, and when in parallel, 1 ohm. 2 ohms, and when in parallel, 1/2 ohm. 1 ohm, and when connected in parallel, 2 ohms. 1/2 ohm, and when in parallel, 2 ohms. none of these

2 ohms, and when in parallel, 1/2 ohm.

Which set of coefficients balance the following chemical equation? ____ AlO3H3 → ____ Al2O3 + ____ H2O 1, 3, 2 4, 2, 6 2, 1, 3 8, 4, 5

2, 1, 3

The current through two identical light bulbs connected in series is 0.25 A. The voltage across both bulbs is 110 V. The resistance of a single light bulb is 440 ohms 44 ohms 220 ohms 22 ohms none of these

220 ohms

The electric power of a lamp that carries 2 A at 120 V is 20 Watts. 2 Watts 240 watts 1/6 watts 60 watts

240 watts

The nucleus of an electrically neutral iron atom contains 26 protons. How many electrons does this iron atom have? 24 52 26 none

26

How many electrons are unpaired in the outermost shell of aluminum (Al, atomic number 13)? 3 2 5 8

3

Two charges separated by 1 m exert a 1-N force on each other. If the magnitude of each charge is doubled, the force on each charge is 8 N 1 N 2 N 4 N none of these

4 N

Which set of coefficients balance the following chemical equation? ____ PH3 + ____ O2 → ____ P4O10 + ____ H2O 2, 4, 1, 6 2, 8, 1, 3 4, 6, 1, 3 4, 8, 1, 6

4, 8, 1, 6

How many electrons are in the outermost shell of phosphorus (P, atomic number 15)? 15 5 3 8

5

How many shells are occupied by electrons in the gold atom (Au, atomic #79)? 5 6 7 4

6

Two lamps, one with a thick filament and one with a thin filament, are connected in parallel to a battery. The voltage is greatest across the lamp with the thin filament. thick filament. Both voltages are the same.

Both voltages are the same.

Which of the following shows elements in order of increasing atomic size (Cl, atomic #17; K, atomic #19; Br, atomic #35; Rb, atomic #37)? K < Br < Rb < Cl Br < Cl < Rb < K Rb < Cl < K < Br Cl < Br < K < Rb

Cl < Br < K < Rb

How is a physical change different from a chemical change? A physical change involves changes in chemical properties. The chemical identity of a substance is not altered during a physical change. The chemical identity of a substance is altered during a physical change. The physical properties of a substance are not altered during a chemical change.

The chemical identity of a substance is not altered during a physical change.

The purpose of coefficients in chemical equations is to make the number of molecules of reactants and products equal. the equation balance by splitting the chemical formula. all the subscripts within the chemical formula equal. The number of times each element appears as a reactant and as a product the same.

The number of times each element appears as a reactant and as a product the same.

Ammonia, NH3, is more polar than is borane, BH3, because it its hydrogens are not exactly opposite one another. has a lone pair of electrons. is less symmetrical than borane. all of the above

all of the above

A molecule has structure mass energy all of these none of these

all of these

A neutral hydrogen atom can attract an additional electron when under high temperatures. because the additional electron finds room in the valence shell. when the hydrogen atom has an additional proton. It is not possible because the atom is electrically neutral.

because the additional electron finds room in the valence shell.

Which force binds atoms together to form molecules? gravitational electrical centripetal nuclear none of these

electrical

The chemical properties of matter come mostly from its electrons protons

electrons

The number of elements in a period is unrelated to the electron capacity of shells. half the electron capacity of the shells. twice the electron capacity of the shells. equal to the electron capacity of the shells.

equal to the electron capacity of the shells.

An electron de-excites from the fourth quantum level to the third and then directly to the first. Two frequencies of light are emitted. How do their combined energies compare to the energy of the single frequency that would be emitted by de-excitation from the fourth level directly to the first level? Answer: The combined energies of the two frequencies emitted by the one electron is equal to the energy of the single frequency. greater than the energy of the single frequency. not predictable because other factors, such as the temperature of the surroundings must also be considered. less than the energy of the single frequency.

equal to the energy of the single frequency.

A hydrogen atom does not form more than one covalent bond because it has such a strong electronegativity. loses its valence electron so readily. has only one electron to share. has only one shell of electrons.

has only one electron to share.

An electron in a 7s orbital has more energy than one in a 1s orbital because it is farther from the nucleus. it is surrounded by more electrons. its principle quantum number is higher. It actually has less energy because of inner-shell shielding.

it is farther from the nucleus.

What drives an atom to form a covalent bond: its nuclear charge or the need to have a filled outer shell? its nuclear charge its need to have a filled outer shell both neither

its nuclear charge

As atoms get more massive they become smaller in size because more massive atoms have a greater number of atomic shells. their mass becomes more concentrated. more mass means more protons, which act to pull electrons in closer to the nucleus. But they don't!

more mass means more protons, which act to pull electrons in closer to the nucleus.

Which of the following are electrically neutral neutron electron proton all of these none of these

neutron

What type of chemical bond would you expect between two chlorine atoms (Cl, atomic #17)? nonpolar covalent ionic polar covalent metallic

nonpolar covalent

To say a chemical equation is balanced means the subscripts on both sides of the reaction add up to the same number. coefficients on both sides of the reaction add up to the same number. number of molecules of reactants and products are equal. number of times each element appears as a reactant is equal to the number of times it appears as a product.

number of times each element appears as a reactant is equal to the number of times it appears as a product.

During a chemical reaction old atoms transform into new ones old atoms disappear to be replaced by new ones old atoms stick around merely switching partners none of the above

old atoms stick around merely switching partners

In an electrically neutral atom, the number of protons in the nucleus is balanced by an equal number of quarks orbital electrons neutrons all of these none of these

orbital electrons

One element is distinguished from another by the number of neutrons protons electrons all of the above

protons

The weight of matter comes mostly from its protons electrons

protons

When the distance between two charges is halved, the electrostatic force between the charges double quadruples halves is reduced by one-quarter none of these

quadruples

Suppose that a certain atom possesses only four distinct energy levels. Assuming that all transitions between levels are possible, how many spectral lines will this atom exhibit? three six four unlimited

six

A 60-Watts light bulb and a 100-Watts light bulb are each rated at 120-V. Which light bulb has a larger resistance? the 100 watts bulb the 60 watts bulb both have the same resistance

the 60 watts bulb

The greater the difference in electronegativity between two covalently bonded atoms, the greater the polarity. the closer together the atoms are located on the perioidic table. the smaller the polarity. Two of the above are correct.

the greater the polarity.

Compared to the amount of electric current that flows in the filament of a lamp, the amount of current that flows in the connecting wire is actually more often less the same definitely less all of these

the same

A circuit is powered with a battery. Current flows through both the battery and the rest of the circuit. out of the battery and into the circuit. after a couple seconds passes. from the negative battery terminal to the positive terminal. none of these

through both the battery and the rest of the circuit.

Which of these atoms has the greatest amount of electrical charge in its nucleus? (use the periodic table) carbon helium gold iron uranium

uranium