Introductory Chemistry

Nivaldo J. Tro

Chapter 1 The Chemical World - all with Video Answers

Educators

Chapter Questions

00:22

Problem 1

Why does soda fizz?

David C.

Numerade Educator

00:29

Problem 2

What are chemicals? Give some examples.

David C.

Numerade Educator

00:41

Problem 3

What do chemists try to do? How do they understand the natural world?

David C.

Numerade Educator

00:53

Problem 4

What is meant by the statement, "Matter does what molecules do"? Give an example.

David C.

Numerade Educator

00:31

Problem 5

Define chemistry.

David C.

Numerade Educator

00:39

Problem 6

How is chemistry connected to everyday life? How is chemistry relevant outside the chemistry laboratory?

David C.

Numerade Educator

00:57

Problem 7

Explain the scientific method.

David C.

Numerade Educator

01:08

Problem 8

Cite an example from this chapter of the scientific method at work.

David C.

Numerade Educator

02:17

Problem 9

What is the difference between a law and a theory?

Eric F.

Numerade Educator

00:35

Problem 10

What is the difference between a hypothesis and a theory?

Himanshu G.

Numerade Educator

00:54

Problem 11

What is wrong with the statement, "It is just a theory"?

David C.

Numerade Educator

00:23

Problem 12

What is the law of conservation of mass, and who discovered it?

David C.

Numerade Educator

00:19

Problem 13

What is the atomic theory, and who formulated it?

David C.

Numerade Educator

00:44

Problem 14

What are three things you need to do to succeed in this course?

David C.

Numerade Educator

00:22

Problem 15

Examine the opening figure of this chapter. Use the information in Section 1.1 to identify the two molecules sitting next to the cola glass and identify each of the atoms within each molecule.

David C.

Numerade Educator

01:06

Problem 16

Examine Figure 1.1 and, from a molecular point of view, explain why soda pop fizzes. What molecules are inside the bubbles in a glass of soda pop?

David C.

Numerade Educator

01:30

Classify each statement as an observation, a law, or a theory.
(a) When a metal is burned in a closed container, the sum of the masses of the container and its contents does not change.
(b) Matter is made of atoms.
(c) Matter is conserved in chemical reactions.
(d) When wood is burned in a closed container, its mass does not change.

David C.

Numerade Educator

01:07

Problem 18

Classify each statement as an observation, a law, or a theory.
(a) The star closest to Earth is moving away from Earth at high speed.
(b) A body in motion stays in motion unless acted upon by a force.
(c) The universe began as a cosmic explosion called the Big Bang.
(d) A stone dropped from an altitude of $450 \mathrm{m}$ falls to the ground in $9.6 \mathrm{s}$.

David C.

Numerade Educator

00:46

Problem 19

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.
$$\begin{array}{lc}
\hline \text { Mass of Gas (in g) } & \text { Volume of Gas (in L) } \\
\hline 22.5 & 1.60 \\
35.8 & 2.55 \\
70.2 & 5.00 \\
98.5 & 7.01 \\
\hline
\end{array}$$

David C.

Numerade Educator

00:39

Problem 20

A student measures the volume of a gas sample at several different temperatures. The results are tabulated as follows. Formulate a tentative law from the measurements.
$$\begin{array}{lc}
\hline \text { Temperature of Gas (in } \mathrm{K} \text { ) } & \text { Volume of Gas (in } \mathrm{L} \text { ) } \\
\hline 298 & 4.55 \\
315 & 4.81 \\
325 & 4.96 \\
335 & 5.11 \\
\hline
\end{array}$$

David C.

Numerade Educator

01:11

Problem 21

A chemist in an imaginary universe does an experiment that attempts to correlate the size of an atom with its chemical reactivity. The results are tabulated as follows.
$$\begin{array}{ll}
\hline \text { Size of Atom } & \text { Chemical Reactivity } \\
\hline \text { small } & \text { low } \\
\text { medium } & \text { intermediate } \\
\text { large } & \text { high } \\
\hline
\end{array}$$
(a) Formulate a law from this data.
(b) Formulate a theory to explain the law.

David C.

Numerade Educator

01:11

Problem 22

A chemist decomposes several samples of water into hydrogen and oxygen and measures the mass of the hydrogen and the oxygen obtained. The results are tabulated as follows.
$$\begin{array}{lll}
\hline \begin{array}{l}
\text { Sample } \\
\text { Number }
\end{array} & \begin{array}{l}
\text { Grams of } \\
\text { Hydrogen }
\end{array} & \begin{array}{l}
\text { Grams of } \\
\text { Oxygen }
\end{array} \\
\hline 1 & 1.5 & 12 \\
2 & 2 & 16 \\
3 & 2.5 & 20 \\
\hline
\end{array}$$
(a) Summarize these observations in a short statement.
Next, the chemist decomposes several samples of carbon dioxide into carbon and oxygen. The results are tabulated as follows:
(b) Summarize these observations in a short statement.
(c) Formulate a law from the observations in (a) and (b).
(d) Formulate a theory that might explain your law in (c).

David C.

Numerade Educator

00:34

Problem 23

The manufacturer of a particular brand of toothpaste claims that the brand contains "no chemicals." Using a few grammatically correct English sentences, describe what you think the company means by that statement. Would a scientist consider the manufacturer's statement to be correct? Why or why not?

David C.

Numerade Educator

00:22

Problem 24

Make a list (including up to ten items) of all the atoms or molecules group members can name off the top of their heads. Get at least one contribution from each group member.

David C.

Numerade Educator

00:55

Problem 25

In your own words, provide a brief definition for each of the following: observation, law, hypothesis, and theory.

David C.

Numerade Educator

00:49

Problem 26

How curious are you? How good are your quantitative skills? How hard are you willing to work to succeed in chemistry? Answer these questions individually on a scale of $1(=\text { not at all })$ to 5 (= very), then share your answers with your group. Report the group average for each question.

David C.

Numerade Educator