Chemistry

Steven S. Zumdahl, Susan A. Zumdahls

Chapter 2 Atoms, Molecules, and lons - all with Video Answers

Educators

Chapter Questions

01:25

Problem 1

Which of the following is true about an individual atom? Explain.
a. An individual atom should be considered to be a solid.
b. An individual atom should be considered to be a liquid.
c. An individual atom should be considered to be a gas.
d. The state of the atom depends on which element it is.
e. An individual atom cannot be considered to be a solid, liquid,
or gas. Justify your choice, and for choices you did not pick, explain what is wrong with them.

Nicole Smina

Numerade Educator

01:25

Problem 2

How would you go about finding the number of "chalk molecules" it takes to write your name on the board? Provide an explanation of all you would need to do and a sample calculation.

David Collins

Numerade Educator

04:11

Problem 3

These questions concern the work of J. J. Thomson.
a. From Thomson's work, which particles do you think he would feel are most important for the formation of compounds (chemical changes) and why?
b. Of the remaining two subatomic particles, which do you place second in importance for forming compounds and why?
c. Propose three models that explain Thomson's findings and evaluate them. To be complete you should include Thomson's findings.

Crystal Wang

Numerade Educator

03:53

Problem 4

Heat is applied to an ice cube in a closed container until only steam is present. Draw a representation of this process, assuming you can see it at an extremely high level of magnification. What happens to the size of the molecules? What happens to the total mass of the sample?

Lena Jake

Numerade Educator

00:26

Problem 5

You have a chemical in a sealed glass container filled with air. The setup is sitting on a balance as shown below. The chemical is ignited by means of a magnifying glass focusing sunlight on the reactant. After the chemical has completely burned, which of the following is true? Explain your answer.
a. The balance will read less than $250.0 \mathrm{~g}$.
b. The balance will read $250.0 \mathrm{~g}$.
c. The balance will read greater than $250.0 \mathrm{~g}$.
d. Cannot be determined without knowing the identity of the chemical.

Ly Tran

Numerade Educator

08:02

Problem 6

You take three compounds consisting of two elements and decompose them. To determine the relative masses of $X, Y$, and $Z$, you collect and weigh the elements, obtaining the following data:
$$\begin{array}{cc}
\text { Elements in Compound } & \text { Masses of Elements } \\
\hline X \text { and } Y & X=0.4 \mathrm{~g}, Y=4.2 \mathrm{~g} \\
Y \text { and } Z & Y=1.4 \mathrm{~g}, Z=1.0 \mathrm{~g} \\
X \text { and } Y & X=2.0 \mathrm{~g}, Y=7.0 \mathrm{~g}
\end{array}$$
a. What are the assumptions in solving this problem?
b. What are the relative masses of $X, Y$, and $Z$ ?
c. What are the chemical formulas of the three compounds?
d. If you decompose $21 \mathrm{~g}$ of compound $X Y$, how much of each element is present?

Julian Taurozzi

Numerade Educator

01:09

Problem 7

The vitamin niacin (nicotinic acid, $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NO}_{2}$ ) can be isolated from a variety of natural sources such as liver, yeast, milk, and whole grain. It also can be synthesized from commercially available materials. Which source of nicotinic acid, from a nutritional view, is best for use in a multivitamin tablet? Why?

Anand Jangid

Numerade Educator

02:32

Problem 8

One of the best indications of a useful theory is that it raises more questions for further experimentation than it originally answered. Does this apply to Dalton's atomic theory? Give examples.

Ricardo Moreno

Numerade Educator

01:14

Problem 9

Dalton assumed that all atoms of the same element were identical in all their properties. Explain why this assumption is not valid.

Mehrnaz Siavoshi

Numerade Educator