Sc 912 P 8 4

George's science teacher has a mixture of table salt and iron filings.
Which of the following would be the best way to separate the salt and the iron filings?

• A.  use a magnet to pull the iron filings from the salt
• add food coloring to the mixture to make the salt change color
• pour them into a beaker of water and see if the iron filings float
• heat up the mixture to see if the salt or the iron filings will burn away

What was Bohr's basic proposal about the atom?

• An electron remains in a fixed position in the space around the nucleus.

• An electron is found in a specific circular path, or orbit, around the nucleus.

• An electron oscillates, or moves back and forth, within one small region of space in the atom.

• An electron readily exchanges position with either a proton or a neutron.

How does the quantum mechanical model differ from the Bohr model in the way it describes the arrangement of electrons in atoms?

• The quantum mechanical model describes electrons as moving anywhere in the atom, not specific circular orbits.

• The quantum mechanical model describes electrons as moving through specific orbits, and not staying in one place.

• The quantum mechanical model places electrons in fixed positions, not moving through specific orbits or orbitals.

• The quantum mechanical model describes electrons as moving through cloud-like orbitals, not specific circular orbits.

The isotopes of hydrogen-1 and hydrogen-2 make up nearly all of the hydrogen found in nature. The mass of hydrogen-1 is 1.0078 amu and the mass of hydrogen-2 is 2.0141 amu. Becuase the average atomic mass of hydrogen is 1.0079 amu what can be concluded about the 2 isotopes of hydrogen?

• Hydrogen-1 is by far the more abundant isotope.

• Hydrogen-2 is by far the more abundant isotope.

• Hydrogen-1 and hydrogen-2 are about equally abundant.

• The isotope hydrogen-3 does not exist in nature.

Answer explanation

Since the average atomic mass is closer in value to the mass of hydrogen-1, we can assume that it is more abundant relative to hydrogen-2.

Tags

SC.912.N.1.1.5

SC.912.P.8.4

FL.SC.912.N.1.1.5

FL.SC.912.P.8.4

What are three types of subatomic particles?

• Ions, neutrons, nucleus

• Protons, electrons, nucleus

• Muons, ions, electrons

• Protons, electrons, neutrons

Tags

FL.SC.912.P.8.4

The atomic mass of oxygen is 15.999 amu. What does this value equal?

• The mass of a randomly chosen oxygen atom

• The mass of every oxygen atom

• The mass of an atom of the most common oxygen isotope

• The weighted average mass of oxygen atoms in nature

Answer explanation

The weighted average is determined by the relative abundance of each oxygen atom and isotopes.

Tags

FL.SC.912.P.8.4

An element has an atomic number of 76. The number of protons and electrons in a neutral atom of the element are ____.

• 152 protons and 76 electrons

• 76 protons and 0 electrons

• 38 protons and 38 electrons

• 76 protons and 76 electrons

Answer explanation

The atomic number also specifies the amount of protons within an element's atom. For a Neutral (charge = 0) atom, the amount of protons and electrons will be equal.

Tags

NGSS.HS-PS1-7

What distinguishes the atoms of one element from the atoms of another?

• The number of protons in the nucleus

• The number of neutrons in the nucleus

• The total number of protons and neutrons in the nucleus

• The total number of protons, neutrons, and electrons

Tags

FL.SC.912.P.8.4

Marshall is interested in how temperature affects the volume of a substance. He conducts an experiment in which he measures the volume of a given mass, in milliliters (ml), at various temperatures, in Kelvin (K). He plots his results, as shown in the graph. From the graph, which of the following can Marshall correctly conclude?

• Energy may change form, but it cannot be created nor destroyed

• Temperature is directly proportional to the volume of a given mass

• Mass may change form, but it can neither be created nor destroyed

• Temperature is inversely proportional to the volume of a given mass

Answer explanation

There is a direct correlation between volume of a given mass and it's temperature as shown by the data in the graph. This is made apparent by the fact that an increase in one variable is accommodated by an increase in the other (As volume increases, so does temperature and vice versa).

Given the hypothesis that the element zinc prevents cancer, which of the following procedures BEST exemplifies the nature of scientific investigation?

• Analyze zinc, looking for allotropic forms

• Do research on zinc and its uses throughout history to determine if there is evidence that zinc prevents incidence of cancer.

• Give zinc supplements to a group of rats and not to another group. After a period of time, determine if there is a higher incidence of cancer in the control group.

• Rely on testimony of friends and relatives, as well as conduct a survey to see if there is a concentration of cancer in the people not taking zinc supplements.