1.1.2 The Scientific Method

Question 1

The Scientific Method

Answer 1

• The scientific method involves making a hypothesis about sets of observations and testing the hypothesis.
• When new observations conflict with a hypothesis, the
  hypothesis is revised or completely discarded for a new
  hypothesis.
• Scientific laws, hypothesis, and theories are all parts of a way to organize observations about the real world.
• If a pattern emerges through several observations, a scientific law may be formulated. A scientific law is a concise statement that summarizes trends in a variety of observations.
• This set of observations may lead to a hypothesis. A
  hypothesis is a tentatively accepted explanation of facts. A hypothesis is an attempt to explain why the patterns of a scientific law are observed.
• If a hypothesis is able to predict the result of several
  experiments, it may develop into a theory. A theory is an encompassing idea that provides a full explanation for a
  natural phenomenon.

Question 2

scientific law

Answer 2

• The scientific method involves making a hypothesis about sets of observations and testing the hypothesis.
• Scientific law, a hypothesis, and a theory are all parts of a way to organize observations about the real world.
• Using the scientific method, scientists came to realize that the world is composed of atoms whose chemical behavior could be explained.

Question 3

law of conservation of mass

Answer 3

• Antoine Lavoisier carried out a series of careful experiments which demonstrated the law of conservation of mass. The law of conservation of mass states that in every chemical change, an equal amount of matter exists before and after the change.
• This scientific law led to a hypothesis that matter was
  composed of indestructible building blocks. This hypothesis was extensively tested.
• This hypothesis led to John Dalton’s atomic theory of matter. This theory was able to predict later observations.

Question 4

In carrying out the experiment of burning paper and making observations, which of the following was not a simple observation that was made about the properties involved in the experiment?

Answer 4

• Ashes from burnt paper weigh more than the unburnt paper.

Question 5

Suppose you do some simple experiments in Denver about cooking eggs. After several experiments you write the following statement: It takes longer to cook eggs because chickens at high altitudes lay eggs with thicker shells. This statement is an example of which of the following?

Answer 5

• a hypothesis
• Hypothesis is the best term because it is a tentative explanation that needs further proof in order to evolve into a theory.

Question 6

Which of the following is not a postulate of Dalton’s atomic theory of matter?

Answer 6

• Atoms can be reduced to protons, electrons and neutrons.

Question 7

After many experiments, scientists knew that phlogiston was a substance that was eliminated from a substance when it burned, losing weight. The concept of phlogiston was eventually rejected after it was observed that some materials actually weighed more after they were burned. Which term in the scientific method best describes the concept of phlogiston?

Answer 7

• theory

Question 8

Which of the following steps is not a part of the scientific method?

Answer 8

• Formulate a theory based on a single observation.

Question 9

What is the term in the scientific method that summarizes the results of repeated observations regarding a given phenomenon without providing an explanation?

Answer 9

• law
• A law is a concise verbal statement that summarizes a broad variety of observations, or a fundamental relationship of nature.

Question 10

According to the Scientific Method, what is the term for a tentative explanation of a scientific event?

Answer 10

• a hypothesis

Question 11

According to Dalton’s atomic theory of matter, what happens during a chemical reaction?

Answer 11

• Atoms rearrange to form new compounds.

Question 12

Which statement best describes the field of chemistry?

Answer 12

• Chemistry is the study of matter.

Question 13

Which of the following statements is not true about a theory?

Answer 13

• A theory is a proven fact that is indisputably true.

Question 14

atomic theory of matter

Answer 14

• all matter is composed of indivisible atoms
• all atoms of a given element are identical in mass and all other properties
• different elements have different atoms; for example, some atoms have different masses
• atoms are indestructible and retain their identities in chemical reactions
• a compound forms from its elements through the combination of atoms of unlike elements in small, whole number ratios