ACS CP Chemical Principles & Laboratory Techniques

Question 1

What is the pH of a neutral solution at 25°C?

Accepted Answer

7

Answer

The pH scale measures the acidity or alkalinity of a solution, ranging from 0 to 14. A neutral solution, like pure water at 25°C, has an equal concentration of hydrogen ions (H+) and hydroxide ions (OH-). This balance results in a pH value of 7, indicating neither acidic nor basic properties.

Question 2

Which laboratory equipment is best for accurately measuring liquid volume?

Accepted Answer

Volumetric flask

Answer

Volumetric flasks are specifically designed and calibrated to measure a precise, fixed volume of liquid with high accuracy. They feature a narrow neck and a single calibration mark, making them ideal for preparing solutions of known concentration. Other equipment like beakers or test tubes are for general use and do not offer the same level of precision for volume measurement.

Question 3

Which technique separates a solid from a liquid?

Accepted Answer

Filtration

Answer

Filtration is a common laboratory technique used to separate insoluble solid particles from a liquid. The mixture is passed through a filter medium, such as filter paper, which retains the solid (residue) while allowing the liquid (filtrate) to pass through. This method relies on the difference in particle size between the solid and liquid components.

Question 4

What safety equipment should be used when handling strong acids?

Accepted Answer

Safety goggles

Answer

When handling strong acids, there is a significant risk of splashes or fumes causing severe eye damage. Safety goggles provide essential protection by creating a barrier that shields the eyes from chemical contact. This is a critical safety measure to prevent serious injury in the laboratory.

Question 5

Which bond involves the sharing of electron pairs between atoms?

Accepted Answer

Covalent bond

Answer

A covalent bond is formed when two atoms share one or more pairs of electrons to achieve a stable electron configuration, typically a full outer shell. This sharing creates a strong attractive force that holds the atoms together in a molecule. In contrast, an ionic bond involves the complete transfer of electrons.

(ACS CP) American Chemical Society (ACS) Certified Professional Practice Test

(ACS CP) American Chemical Society (ACS) Certified Professional Practice Test

ACS CP Chemical Principles & Laboratory Techniques