Praxis Biology: Molecular Structure Basics Chapter Exam

Exam Instructions:

Choose your answers to the questions and click 'Next' to see the next set of questions. You can skip questions if you would like and come back to them later with the yellow "Go To First Skipped Question" button. When you have completed the practice exam, a green submit button will appear. Click it to see your results. Good luck!

Page 1

Question 1 1. Particles that are found in the atomic nucleus are:

Question 2 2.

Which of the following statements accurately describe ice:

I. Ice is denser than water.

II. Hydrogen bonds hold ice molecules closer together than they do liquid water molecules.

III. Ice has a crystalline structure.

Question 3 3.

If a carbon atom has four valence electrons, which of the following statements are true?

I. Carbon can form a triple covalent bond with another carbon atom.

II. A carbon atom cannot form two double bonds simultaneously.

III. A carbon atom can form four single covalent bonds simultaneously.

Question 4 4. What does the atomic number represent?

Question 5 5. If Argon is a noble gas and its atomic number is 18, how many electrons can be found in the valence level?

Page 2

Question 6 6.

Which of the following statements are true?

I. Noble gases complete their valence level by sharing electrons.

II. Covalent bonds are weak and easily broken.

III. Covalent bonds allow us to make predictions on how the molecule will look.

Question 7 7. Which of the following concepts best describes a chlorophyll molecule absorbing light and changing it into chemical energy?

Question 8 8.

Which of the following statements is true?

I. In an ionic bond, electrons move toward the atom that is more electronegative.

II. A cation is a negatively charged atom.

III. A positively charged atom is called an anion.

IV. Under biological conditions, ionic bonds are stronger than covalent bonds.

Question 9 9.

Given the following information, which element(s) are most likely to lose electrons?

I. Iodine is a member of Group VII (halides).

II. Strontium is located in the second column of the periodic table.

III. Selenium has six valence electrons.

Question 10 10. If only one type of atom makes up a substance, what can you call this substance?

Page 3

Question 11 11. Which of the following is NOT a hydrophobic substance?

Question 12 12. Which of the following solutes would NOT form a solution if added to water?

Question 13 13. What do you think would happen if you added a sugar crystal to a super saturated solution of sugar in water?

Question 14 14. Which of the following is a strong acid?

Question 15 15. Which of the following atoms is most likely to participate in an ionic bond with chlorine, an atom with 7 valence electrons?

Page 4

Question 16 16.

The second law of thermodynamics states that:

I. Energy can neither be created nor destroyed

II. All free energy cannot be converted into usable energy

III. The entropy of a system increases over time

Question 17 17. What is the process of water moving across a semipermeable membrane?

Question 18 18. Two different molecules can participate in which of the following bonds?

Question 19 19. An element is defined by the number of:

Question 20 20. Which of the following is NOT true?

Page 5

Question 21 21.

Which of the following statements are true?

I. Water molecules can form hydrogen bonds with sodium chloride.

II. Water molecules can form an ionic bond with other water molecules.

III. The hydrogen of a water molecule can form a hydrogen bond with the hydrogen of another water molecule.

Question 22 22. What would you expect to happen to a piece of celery you put into a hypertonic solution?

Question 23 23. Which of the following properties helps explain why a city near the Pacific Ocean experiences less dramatic changes in temperature during the day compared to a city farther inland?

Question 24 24. Two atoms with the same electronegativity would form what kind of bond?

Question 25 25. Which of the following has a positive charge and a mass of one amu?

Page 6

Question 26 26. Which of the following is an example of diffusion?

Question 27 27. Which of the following statements is true?

Question 28 28. What is the maximum number of electrons that can occupy the 2s orbital?

Question 29 29. If a silicon atom has four valence electrons, what is the maximum number of bonds it can form?

Question 30 30.

What differentiates a nonpolar covalent bond from a polar covalent bond?

I. Unequal sharing of electrons

II. Ions

III. Atoms of partial charge

Praxis Biology: Molecular Structure Basics Chapter Exam Instructions

Choose your answers to the questions and click 'Next' to see the next set of questions. You can skip questions if you would like and come back to them later with the yellow "Go To First Skipped Question" button. When you have completed the practice exam, a green submit button will appear. Click it to see your results. Good luck!

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