Unit 1 Makeup

Dimensional Analysis and Waves

Practice your knowledge of dimensional analysis and waves

Conversion factors that we use when...

Multiple Choice

What conversion factor would you use to determine how many moles are in 5.8 grams of water (H₂O)?

• 1 mol = 6.02 x 10²³ particles

• 1 mol = molar mass (g)

• 6.02 x 10²³ particles = molar mass (g)

• None of the above

Multiple Choice

What conversion factor would you use to determine how many moles are in 78 atoms of Na?

• 1 mol = molar mass

• 1 mol = 1 mol

• 1 mol = 6.02 x 10²³ particles

• 1 mol = 62 x 10²³ particles

Converting particles to grams

Converting grams to particles

Multiple Choice

How will you determine the amount of grams in 4.5 atoms of Na?

• Convert 4.5 atoms to grams (molar mass), then to moles (avogadro's number)

• Convert 4.5 atoms to grams (molar mass), then to moles (avogadro's number)

• Convert 4.5 atoms to moles (avogadro's number), then to grams (molar mass)

• Convert 4.5 atoms to particles, then to grams

Multiple Choice

How would you determine the amount of particles in 9.2 grams of MgO₂?

• Convert 9.2 grams to moles only.

• Convert 9.2 atoms to moles (avogadro's number), then to grams (molar mass)

• Convert 9.2 grams to particles (avogadro's number), then to moles (molar mass)

• Convert 9.2 grams to moles (molar mass), then to particles (avogadro's number)

Multiple Choice

Which of the following shows the correct set up to convert from moles to grams?

• $$mol\times\frac{grams}{mol}$$

• $$mol\times\frac{mol}{grams}$$

• $$grams\times\frac{mol}{grams}$$

• None of the above

Setting up dimensional analysis:

Multiple Choice

How will you determine the amount of grams in 4.5 atoms of Na?

• Convert 4.5 atoms to grams (molar mass), then to moles (avogadro's number)

• Convert 4.5 atoms to grams (molar mass), then to moles (avogadro's number)

• Convert 4.5 atoms to moles (avogadro's number), then to grams (molar mass)

• Convert 4.5 atoms to particles, then to grams

Multiple Choice

Determine how many molecules of water are in 4.5 g of water. What should be used to complete the dimensional analysis set up below?

$$4.5\ g\ H_2O\ \times\frac{1\ mol}{18.02\ g\ H_2O}\times\frac{?\ molecules}{1\ mol}$$  

• Molar mass of water

• Avogadro's Number (6.02 x 10^23)

• Atomic mass of hydrogen

• 1 molecule

Multiple Choice

Calculate how many grams are in 3.4 moles of water by completing the dimensional analysis set up below:

$$?\ \times\frac{18.02\ g}{1\ mol}$$  

• 18.02 moles

• 3.4 moles

• 3.4 grams

• 18.02 grams

Multiple Choice

Determine how many grams of water are in 34 molecules of water by finishing the dimensional analysis set up below:

$$34\ molecules\ \times\frac{1\ mol}{6.02\times10^{23}\ molecules}\times\frac{18.02\ ?}{1\ mol}$$  

• moles

• molecules

• grams

• atoms

Multiple Choice

When converting from particles to grams, how should the dimensional analysis be set up?

• $$particles\ \times\frac{particles}{mol}\times\frac{gram}{mol}$$

• $$particles\ \times\frac{mol}{particles}\times\frac{mol}{grams}$$

• $$particles\ \times\frac{mol}{particles}\times\frac{gram}{mol}$$

• $$grams\ \times\frac{mol}{particles}\times\frac{particles}{mol}$$

Wave Characteristics

L.O. investigate and analyze characteristics of waves and the relationship between frequency, wavelength & energy.

Relationship between frequency, wavelength and energy?

• Shorter wavelengths and higher the frequency -> greater energy.

• Longer wavelengths and lower the frequency -> lower energy.

Multiple Choice

Which of the following waves has GREATER energy?

• Wave a

• Wave b

• They both have the same amount of energy

Relationship between frequency, wavelength and energy?

• Frequency = c / wavelength

• c = speed of light = 3.0 x 10⁸ m/s (m/s is a UNIT)

• Energy = frequency x h

• h = Planck's constant = 6.626 x 10^-34 s^-1 (s^-1 is a UNIT. DO NOT count it as part of the number)

Math Response

The frequency of a lavender flame is 7.14 x 10¹⁴ s^-1. Determine the amount of energy in Joules (J) of the flame. Round to TWO decimal places.

Type answer here

Correct Answer: 4.73\times10^{-14}

Deg^°

Rad