Ch 2 Measurements & Calculations

Which of these observations is qualitative rather than quantitative?

• A chemical reaction is complete in 2.3 s.

• The solid has a mass of 23.4 g.

• The density of aluminum is 2.70 g/cm3.

• Salt deposits form from an evaporated liquid.

Quantitative observations are recorded in the form of

• numerical data.

• detailed descriptions.

• precise predictions.

• step-by-step procedures.

All of the following are steps in the scientific method except

• observing and recording data.

• forming a hypothesis.

• discarding data inconsistent with the hypothesis.

• making predictions based on a theory.

Which of these statements about the scientific method is not true?

• All experiments must follow the same step-by-step procedure.

• Experiments may be repeated several times.

• Some unexpected results can be beneficial.

• Experimental results may or may not support the hypothesis.

Ten plants are grown in equal amounts of sunlight with equal amounts of water and varying amounts of fertilizer. Sunlight, water, and fertilizer are

• controls.

• experiments.

• systems.

• variables.

An experiment was designed to measure the effect of sulfur dioxide emissions from a power plant on the pH of rain falling downwind of the plant. In this experiment, the average pH of rainwater upwind from the plant would be considered

• a model.

• a variable.

• the hypothesis.

• the control.

Which of these best describes a scientific model?

• a small version of a large object

• the most recent version of a theory

• a way of explaining a complex concept

• a detailed description of a natural event

A proposed explanation that is based on observations and that can be tested is known as a(n)

• principle.

• experiment.

• law.

• hypothesis.

For each investigation, the scientific method

• requires that the same set of procedures be followed.

• provides a logical set of procedures.

• is abandoned if there are unexpected results.

• helps to predict the results.

A theory is accepted as the explanation of an observed phenomenon until

• one study contradicts the theory.

• repeated observations conflict with the theory.

• a new method is used to gather data.

• a leading scientist feels that it is invalid.