Question 1

A scientist is measuring the density of an unknown liquid. She records the following masses and volumes: 25.0 g in 20.0 mL, 37.5 g in 30.0 mL, and 50.0 g in 40.0 mL. What is the density of the liquid, and what does this indicate about the precision and accuracy of her measurements if the true density is 1.25 g/mL?

Accepted Answer

Density is $$1.25\ \mathrm{g/mL}$$; measurements are both precise and accurate.

Question 2

Which of the following best describes the role of a buffer in a biological system?

Accepted Answer

A buffer maintains a stable pH by neutralizing small amounts of added acid or base.

Question 3

A student adds a solid ionic compound to water and observes that the solution conducts electricity. Which property of the compound is responsible for this observation?

Accepted Answer

The compound dissociates into ions, making it an electrolyte.

Question 4

Which of the following best explains why water forms a meniscus in a graduated cylinder?

Accepted Answer

Adhesion between water molecules and glass causes the surface to curve downward.

Question 5

A solution is prepared by dissolving $$0.5$$ moles of NaCl in enough water to make $$1.0$$ liter of solution. What is the molarity ($$M) of $$the solution?

Accepted Answer

$$0.5\ M$$

Question 6

Which part of a compound microscope is responsible for focusing light onto the specimen?

Accepted Answer

Condenser

Question 7

A scientist hypothesizes that increasing light intensity will increase the rate of photosynthesis in algae. In her experiment, what is the independent variable?

Accepted Answer

Light intensity

Question 8

Which of the following best describes a hydrogen bond?

Accepted Answer

A weak attraction between a hydrogen atom bonded to oxygen, nitrogen, or fluorine and another electronegative atom.

Question 9

A solution has a pH of $$4. $$Which of the following statements is correct?

Accepted Answer

The solution is acidic and has a high concentration of hydrogen ions ($$[H^+]).$$

Question 10

Which of the following best describes cytoplasmic streaming?

Accepted Answer

The movement of cytoplasm within a cell to help transport materials.

Question 11

A student is using a compound microscope with a $$10	imes$$ ocular lens and a $$40	imes$$ objective lens. What is the total magnification?

Accepted Answer

$$400	imes$$

Question 12

Which of the following is an example of a cation?

Accepted Answer

$$\mathrm{Na^+}$$

Question 13

A scientist uses a standard curve to determine the concentration of an unknown protein sample. Which property is most likely measured to create the standard curve?

Accepted Answer

Absorbance at a specific wavelength

Question 14

Which of the following best describes the octet rule?

Accepted Answer

Atoms tend to gain, lose, or share electrons to have eight electrons in their outer shell.

Question 15

A student adds $$10.0\ \mathrm{g} of a $$solid to a graduated cylinder containing $$50.0\ \mathrm{mL} of $$water. The water level rises to $$55.0\ \mathrm{mL}. $$What is the density of the solid?

Accepted Answer

$$2.0\ \mathrm{g/mL}$$

Question 16

Which of the following statements about acids and bases is correct?

Accepted Answer

Acids release $$\mathrm{H^+}$$ ions in water, while bases accept $$\mathrm{H^+} or $$release $$\mathrm{OH^-}$$ ions.

Question 17

Which of the following best describes the difference between a covalent bond and an ionic bond?

Accepted Answer

A covalent bond involves sharing electrons, while an ionic bond involves transferring electrons.

Question 18

Which of the following is the correct molecular formula for a molecule containing two hydrogen atoms and one oxygen atom?

Accepted Answer

$$\mathrm{H_2O}$$

Question 19

Which of the following best describes the function of the iris diaphragm on a compound microscope?

Accepted Answer

It controls the amount of light reaching the specimen.

Question 20

Which cellular structure is directly involved in the light-dependent reactions of photosynthesis?

Accepted Answer

Thylakoid

Fundamental Concepts in Biology: Measurements, Chemistry, Microscopy, and Cell Biology

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