Quiz 2 - Chemistry and the Scientific Method | Chemistry and the Scientific Method

1

What aspect of scientific measurement inherently includes uncertainty?

Measurements that involve estimation, particularly of decimals, inherently include uncertainty. This is because there is always a degree of approximation when assessing values beyond exact counts or discrete units.

2

When a chemist uses dimensional analysis to convert from grams to moles, which of the following principles is being applied?

Utilizing dimensional analysis to convert from grams to moles applies the mole concept, where molar mass serves as a conversion factor, allowing one to switch between mass and quantity of substance.

3

Which scenario best illustrates a quantitative observation in the scientific method?

Measuring a compound's boiling point is a quantitative observation because it provides numeric data concerning a specific property of matter, unlike qualitative observations like color, or predictive tasks.

4

A chemist records the mass of a compound as 5.487 g, which includes known and estimated digits. What term best describes the 7 in this measurement?

The 7 in the measurement is described as a significant figure, which indicates the precision of the measurement; it includes all known digits and the last estimated digit.

5

In the context of the International System of Units (SI), why is it important for scientists to use standardized units of measurement?

Using standardized units of measurement, such as SI units, is crucial to ensure that scientific results are consistent, comparable, and reproducible worldwide, regardless of where measurements are taken.

6

A researcher calculates the yield of a chemical reaction to be 7.56 ± 0.02 grams. Which part of the reported value addresses the uncertainty in measurement?

The plus-minus range of ± 0.02 grams explicitly states the uncertainty associated with the measurement of the chemical reaction's yield, giving a margin of error around the calculated value.

7

Which of the following best illustrates the property of matter that is both extensive and intensive?

Density is both extensive and intensive. It is extensive as it depends on the amount of substance present (mass over volume) but also intensive as it remains constant regardless of sample size.

8

What is the purpose of using significant figures in scientific measurements?

Significant figures represent the precision of measurements by including all known digits and a final estimated digit. This prevents the overestimation of accuracy in calculated numerical results.

9

How does the scientific method promote the advancement of scientific knowledge?

The scientific method is a systematic approach that fosters scientific inquiry. By emphasizing repeatable experiments and encouraging scrutiny through peer review, it allows for the verification and evolution of scientific knowledge.

10

A chemist observes that increasing the pressure on a gas reduces its volume. This observation best relates to:

The chemist's observation relates to the properties of matter in its gaseous state. It is an empirical manifestation of Boyle's Law, which states that pressure and volume are inversely proportional for a given amount of gas at constant temperature.

11

What does the use of dimensional analysis in chemical calculations exemplify?

Dimensional analysis is a mathematical technique used to convert between units. This method exemplifies the connection between various units of measurement and shows the necessity of accurately converting them to analyze scientific data correctly.