Subject: basic4
From: Michele Gressman
Date: Tue, 27 Sep 2005 18:32:52 -0700 (PDT)
To: Larry Rudnick


1.

Incorrect What is a joule?

Your Answer:

It is the term used for an atom that has a different number of electrons than protons.

Correct Answer:

It is the standard unit of energy used in science.
  An atom that has a different number of electrons than protons is an ion.

2.

Incorrect The energy attributed to an object by virtue of its motion is known as _________

Your Answer:

radiative energy.

Correct Answer:

kinetic energy.
  Radiative energy is carried by photons of light.

3.

Correct Absolute zero is

Your Answer:

0 degrees Kelvin
  Correct.

4.

Correct Sublimation is the process in which ___________

Your Answer:

molecules go directly from the solid phase to the gas phase.
  Correct.

5.

Correct An atom that has fewer electrons than protons is called a/an

Your Answer:

ion.
  An atom that has a number of protons that does not equal the number of electrons is an ion.

6.

Correct Consider an atom of carbon in which the nucleus contains 6 protons and 7 neutrons. What is its atomic number and atomic mass number?

Your Answer:

Atomic number = 6; atomic mass number = 13.
  Correct.

7.

Incorrect Consider an atom of oxygen in which the nucleus contains 8 protons and 8 neutrons. If it is doubly ionized, what is the charge of the oxygen ion and how many electrons remain in the ion?

Your Answer:

Charge is +2; number of remaining electrons = 8.

Correct Answer:

Charge is +2; number of remaining electrons = 6.
  Because oxygen has 8 protons, it is neutral if it also has 8 electrons.

8.

Incorrect Each of the following describes an "Atom 1" and an "Atom 2." In which case are the two atoms different isotopes of the same element?

Your Answer:

Atom 1: nucleus with 6 protons and 8 neutrons, surrounded by 6 electrons.Atom 2: nucleus with 7 protons and 8 neutrons, surrounded by 7 electrons.

Correct Answer:

Atom 1: nucleus with 7 protons and 8 neutrons, surrounded by 7 electrons.Atom 2: nucleus with 7 protons and 7 neutrons, surrounded by 7 electrons.
  These are not isotopes of one another because they represent two different elements (with different atomic number).

9.

Incorrect In the formula E=mc2, what does E represent?

Your Answer:

The radiative energy carried by light.

Correct Answer:

The mass-energy, or potential energy stored in an object's mass.
  Sorry.

10.

Incorrect Radiative energy is __________

Your Answer:

energy of motion.

Correct Answer:

energy carried by light.
  Sorry.

11.

Correct The nucleus of an atom may contain

Your Answer:

protons and neutrons.
  Correct.

12.

Correct What does temperature measure?

Your Answer:

The average kinetic energy of particles in a substance.
  Correct.

13.

Incorrect What is a plasma?

Your Answer:

A gas consisting of freely moving protons and neutrons.

Correct Answer:

A gas of in which many of the atoms are ionized, so that there are charged ions and electrons moving around.
  Sorry.

14.

Incorrect Which of the following best describes the fundamental difference between two different chemical elements (such as oxygen and carbon)?

Your Answer:

They have different atomic mass numbers.

Correct Answer:

They have different numbers of protons in their nucleus.
  This is not a fundamental difference between chemical elements. For example, carbon--14 and nitrogen--14 have the same atomic mass number of 14, but they are different elements.

15.

Incorrect Which of the following statements correctly describes the law of conservation of energy?

Your Answer:

The total kinetic energy of the particles in any substance must always stay the same.

Correct Answer:

The total quantity of energy in the universe never changes.
  Kinetic energy can change into other forms of energy.

16.

Incorrect Which of the following transitions is not possible?

Your Answer:

An electron begins in the ground state and then gains enough energy to jump to an excited state.

Correct Answer:

An electron begins in an excited state and then gains enough energy to jump to the ground state.
  This is possible, but the question asks for a transition that is NOT possible.



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