Which of the following best describes the meaning of molar mass?

• a) the mass of one mole of electrons
• b) the mass of one mole of water
• c) the mass of one mole of a substance
• d) the volume that a mole of a given mass occupies
• e) the mass of one of your back teeth

Why is the mass corresponding to a mole of one element different from the mass corresponding to a mole of another element ?

How many grams of solid iron (III) chloride ($\mathrm{FeCl_{3}}$) are produced when 2.00 moles of solid iron (Fe) are combined with chlorine gas $\left(\mathrm{Cl}_{2}\right)$?

1. Analyze the Problem Known: __________ Unknown: __________ You are given the moles of the reactant, Fe, and must determine the mass of the product, $\mathrm{FeCl_{3}}$, therefore, you will do a mole to mass conversion.
2. Solve for the Unknown Write the balanced chemical equation. Identify the known and unknown substances.

$$\mathrm{Fe}(\mathrm{s})+\square \mathrm{Cl}_{2}(\mathrm{g})=\square \mathrm{FeCl}_{3}(\mathrm{s})$$

List the mole ratios for this equation. Multiply the number of moles of Fe by the mole ratio.

$$\square \text{mol Fe} \times \frac{\square \mathrm{mol} \ \mathrm{FeCl_{3}}}{\square\mathrm{mol \ Fe}} = \square \mathrm{mol \ FeCl_{2}}$$

Multiply the moles of $\mathrm{FeCl}_{3}$ by the molar mass of $\mathrm{FeCl}_{3}$.

$$\operatorname{mol} \mathrm{FeCl}_{3} \times \frac{\mathrm{g} \mathrm{FeCl}_{3}}{1 \mathrm{mol} \mathrm{FeCl}_{3}}=\square \mathrm{gFeCl}_{3}$$

3. Evaluate the Answer The given number of moles has $\square$ digits, so the mass of $\mathrm{FeCl}_{3}$ must have $\square$ digits.

Organize the following equations by drawing a line from type of conversion to the correct equation.

$$\text{mole to mass} \qquad \text{mass} \times \frac{1 \text { mole }}{\text { number of grams }}$$

$$\text{mass to mole} \qquad\left\{\begin{array}{l} \operatorname{mass} \times \frac{1 \mathrm{mole}}{\text { number of grams }}, \\ \text { moles } \times \frac{6.02 \times 10^{23}}{1 \mathrm{mole}} \end{array}\right.$$

$$\text{mass to atoms} \qquad \text{number of moles} \times \frac{\text { number of grams }}{1 \mathrm{mole}}$$

$$\text{atom to mass} \qquad \left\{\begin{array}{l} \operatorname{atoms} \times \frac{1 \mathrm{mole}}{6.02 \times 10^{23}}, \\ \mathrm{moles} \times \frac{\text { number of grams }}{1 \mathrm{mole}} \end{array}\right.$$

Draw a concept map that relates the following mole quantity.

mass of chloroform and molecules of chloroform, $\mathrm{CHCl}_3$

Discuss the relationships that exist between the mole, molar mass, and Avogadro's number.

Discuss the relationships that exist between the mole, molar mass, and Avogadro’s number.

What is $pH$?

A) the negative logarithm of the hydrogen ion concentration

B) the positive logarithm of the hydrogen ion concentration

C) the negative logarithm of the hydroxide ion concentration

D) the positive logarithm of the hydroxide ion concentration

The lower the $\ce{pH}$ of a solution, the ______.

A) greater the number of oxygen atoms

B) more acidic the solution

C) less toxic the solution

D) higher the $\ce{OH^-}$ concentration

In the pH scale, the lower the pH, the higher the hydrogen ion concentration. True or False

You are given two samples of carbon. The first sample, carbon-12, has a mass number of 12, the second sample, carbon-13, has a mass number of 13. Both samples have an atomic number of 6. Determine the number of protons, electrons, and neutrons in each sample.

1. Analyze the Problem Known: Carbon-12 Mass number is _____ Atomic number is _____ Carbon-13 Mass number is _____ Atomic number is ____ Unknown: The number of protons, electrons, and neutrons in each sample.
2. Solve for the Unknown Number of protons = number of electrons = atomic number = ____ Number of neutrons = mass number - atomic number The number of neutrons for carbon-12 = 12 - 6 = _____ The number of neutrons for carbon-13 = 13 - 6 = _____
3. Evaluate the Answer The number of neutrons does equal the ________ minus the _______, or the number of protons.

Why is the depth of field important in studying biological structures? How can it affect your ability to find and examine a specimen?

Examine the micrograph of the letter $e$ shown in figure 3.4. This letter is magnified $40 \times$. What is the actual height of the letter?

What means to increase the scan field of view?