Bio 240 Practice Exam 1

Two neutral atoms with the same mass number and different atomic number:

• A. Are isotopes the same element

• B. Are two different elements

• C. Have the same number of electrons

• D. Have the same number of protons

• Both C and D

Which of the following atoms has the lowest number of valence electrons? Assume all are neutral.

• A. Carbon (atomic # = 6)

• B. Sulfur (atomic # = 16)

• C. Lithium (atomic # = 3)

• D. Silicon (atomic # = 14)

• E. Nitrogen (atomic # = 7)

Tags

NGSS.HS-PS1-1

Which of the following is true of the ion 22Na+? (Atomic number of neutral Na = 11)

• A. It has the same atomic number as a neutral Na atom

• B. It has the same number of electrons as a neutral Na atom

• C. It is an isotope of sodium

• D. A and B are both true

• E. None of the above

Tags

NGSS.HS-PS1-3

Nitrogen is much more electronegative than hydrogen. Which of the following statements is true about ammonia (NH3)?

• The nitrogen atom has a complete negative charge

• Each hydrogen atom has a partial positive charge

Tags

NGSS.HS-PS1-1

Which molecule is hydrophobic?

• A. HF

• B. H2

• C. CH4

• D. All of the above

• E. B and C

Which of the following is least likely to dissolve in water?

• A. Polar molecules

• B. Nonpolar molecules

• C. Ionic compounds

• D. Hydrophilic molecules

• E. All of the above are likely to dissolve in water

Tags

NGSS.HS-PS1-1

Which property of water allows you to fill a cup with water a little bit over the rim without it spilling over?

• A. Solvent of life

• B. Adhesion/cohesion

• C. Temperature moderation

• D. Expansion upon freezing

• E. None of the above

Tags

NGSS.HS-ESS2-5

Water is such a good solvent because:

• A. The bonds in water are non-polar and interact with every kind of particle

• B. Water molecules are polar, so they can dissolve ions and polar molecules

• C. The bonds are ionic, so they can bond with ions

• D. It has a high specific heat, so it exhibits temperature moderation

• E. It can dissolve nonpolar organic compounds

Adding an acid to a solution will:

• A & D

• A. Increase [H+]

• B. Increase pH

• C. Increase [OH-]

• D. Decrease pH

The pOH of a solution is 2. Which of the following are true?

• A. The solution is basic

• B & C

• B. The solution is acidic