Moles and Conversions

Multiple Choice

Why is the concept of the mole important in chemistry?

• It allows chemists to count particles by weighing them

• It helps chemists to identify elements

• It is used to measure temperature

• It is used to measure volume

Open Ended

How does the relationship between atomic mass in amu and molar mass in grams help chemists in practical applications?

Multiple Choice

What is the difference between formula mass and molecular mass?

• Formula mass is used for ionic compounds, while molecular mass is used for molecular compounds.

• Formula mass is measured in grams, while molecular mass is measured in amu.

• Formula mass is used for molecules, while molecular mass is used for ions.

• Formula mass and molecular mass are always the same.

Fill in the Blanks

For any ionic compound, formula mass (amu) =

(grams)

Open Ended

Explain how the mass of one mole of a substance is related to its atomic or molecular mass in amu.

Open Ended

Why is it important to be able to convert between grams and moles in chemistry?

Multiple Select

Which of the following statements are true about molar mass?

• Molar mass allows conversion between grams and moles.

• Molar mass is calculated by adding the masses of all atoms in a formula.

• Molar mass is only used for elements, not compounds.

• Molar mass can be measured in the lab.

Fill in the Blanks

A conversion factor is a fraction or ratio whose numerator and denominator have different units but are

Multiple Choice

Which of the following best describes what a conversion factor does in dimensional analysis?

• It introduces the unit you want in the numerator and cancels out the original given unit in the denominator.

• It multiplies the original unit by a constant.

• It adds units together to form a new unit.

• It divides the original unit by a random number.

Multiple Select

Which of the following are valid conversion factors for 1 hour?

• 1 hour / 60 min

• 60 min / 1 hour

• 1 min / 60 hour

• 60 hour / 1 min

Open Ended

Explain how dimensional analysis helps in converting between different units. Use examples from the slides to support your answer.

Fill in the Blanks

To convert from mass to moles, the conversion factor should have

in the numerator and grams in the denominator.

Open Ended

How would you convert 3.2 mol of Zn(NO3)2 to grams? Describe the steps and the conversion factor used.

Multiple Choice

How many moles is 8.74 formula units of CaCO3?

• 1.45 mol

• 8.74 mol

• 6.022 mol

• 0.145 mol

Open Ended

What is Avogadro's number and how is it used in mole to particle conversions?

Multiple Choice

Which of the following steps are required to convert grams of a compound to molecules?

• Convert grams to moles using molar mass, then convert moles to molecules using Avogadro's number

• Convert grams directly to molecules using Avogadro's number

• Convert grams to atoms using atomic mass, then to molecules

• Convert grams to liters, then to molecules

Fill in the Blanks

Convert 76.0 grams of MgO to formula units of MgO. Fill in the blank: The answer is

x 10^25 Form. U.

Labeling

4 FeS + 7 O₂ → 2 Fe₂O₃ + 4 SO₂

Place the numbers in the correct spots to solve this problem: how many moles of SO₂ will be produced if you use 19.6 moles of O₂?

Drag labels to their correct position on the image

19.6 mol SO2

4 mol SO2

7 mol FeS

4 mol FeS

7 mol O2

2.8 mol SO2

2 mol Fe2O3

34.3 mol SO2

11.2 mol SO2

19.6 mol O2

Labeling

How many moles are in 2.2x10²⁴ atoms of argon?

Drag labels to their correct position on the image

6.02x10²³ formula units

6.02x10²³ atoms

1 mole

0.27 moles

6.02x10²³ molecules

1.3x10⁴⁸ moles

2.2x10²⁴ atoms

6.02x10²³ moles

3.7 moles

6.02x10²³ compounds

Fill in the Blanks

The atomic mass in

is equal to the molar mass in grams.

Open Ended

How does the concept of the mole help chemists count particles in a substance?