HW - Chapter 1
1. Scientific Theory
Which is true about scientific theories?
a theory is a model that explains the underlying reasons for observations and scientific laws
a theory briefly summarizes past observations and predicts future ones
a theory is a scientific opinion with very little observations to support it
a theory is a method of learning that emphasizes reason as the way to understand the world
none of the other answers apply
2. Exercise 1.17
Classify each of the following as an observation, a law, or a theory. Part A - When a metal is burned in a closed container, the mass of the container and its contents do not change. ANSWER:
Part B - Matter is made of atoms.
Part C - Matter is conserved in chemical reactions.
Part D - When wood is burned in a closed container, its mass does not change. ANSWER:
3. Exercise 1.5
Part A - Define chemistry.
Chemistry is the science that seeks to understand what matter does by studying what atoms and molecules do.
Chemistry is the science of matter and its motion, as well as space and time - the science that deals with concepts such as force, energy, mass, and charge.
Chemistry is the science that studies the molecular transformations only in nonliving matter.
Chemistry is the science that studies the molecular transformations only in living matter.
4. Exercise 1.12
Part A - What is the law of conservation of mass?
In a chemical reaction, matter is neither created nor destroyed.
In a chemical reaction, matter is created and destroyed.
In a chemical reaction number of atoms remains constant.
In a chemical reaction energy remains constant but cannot be recreated, although it may change forms.
Part B - Who discovered it?
5. Exercise 1.13
Part A - What is the atomic theory?
All matter is composed of small, indestructible particles called atoms.
"In a chemical reaction, matter is neither created nor destroyed."
Part B - Who formulated the atomic theory?
6. Exercise 1.14
What are three things you need to do to succeed in this course? Check all that apply.
7. Exercise 1.16 The picture required for the next question can be found at http://courses.mglittle.com/wp-content/uploads/c1cover.jpg Part A - What molecules are inside a bubble within soda pop? ANSWER:
8. Exercise 1.19
Part A - A student prepares several samples of the same gas and measures their mass and volume. The results are tabulated as follows. Formulate a tentative law from the measurements. Mass of Gas (in grams)
Volume of Gas (in )
Check all that apply.
The mass of a gas is directly proportional to its volume.
The mass to volume ratio of a gas is constant.
The mass to volume ratio of a gas isn't constant.
The mass of a gas is inversely proportional to its volume.
9. Exercise 1.2
Part A - What are chemicals?
Chemicals are poisons (e. g. insecticides).
Chemicals are what make up everything around us, including ourselves.
Chemicals are the substances which are used in agriculture.
Chemicals are inorganic substances.
Part B - Give some examples of pure chemical substances.
Soda water and brass.
Sugar, carbon dioxide and water.
Bronze and brass.
10. Exercise 1.10
Part A - What is the difference between a hypothesis and a theory? ANSWER:
A scientific theory and a...
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