Investigation 8 Review

Moles & Molecules

Avogadro's

Percent Composition

Concentrations

Formulas & Relationships

100

How many pages of paper would you have if you had one mole of paper?

6.02x10²³pages of paper

100

What is Avogadro's number?

6.02x10²³

100

If the formula of a compound is N₅H₁₀Cl₂, then what is the ratio of nitrogen to hydrogen to chlorine?

5 : 10 : 2

100

What are the units for concentation?

moles/Liter

100

What is the empirical formula for the compound: N₄H₁₀Br₂?

N₂H₅Br

200

What three variables can you convert between by using moles?

Number of particles, Mass, and Volume

200

What is the representative particle for an ionic compound?

Formula Units

200

If the percent composition of a compound is:

25% Carbon

10% Hydrogen

65% Oxygen

then what is the mass of oxygen in a 100 gram sample of that compound?

65 grams

200

In this chapter, we learned that concentration is also known as _________________.

Molarity

200

Write down an example of another molecular formula that has the same empirical formula as C₃H₄O₂?

C₆H₈O₄

C₉H₁₂O₆

C₁₂H₁₆O₈

C₁₅H₂₀O₁₀

300

If you have one mole of copper, one mole of silver, and one mole of gold, then which one will weigh the most or will they all weigh the same?

One mole of gold will weigh the most because it has the biggest molar mass.

300

Avogadro's hypothesis says that the volume of a gas is directly proportional to ______________________.

The number of gas particles

300

What law serves as the foundation for being able to calculate the percent composition of a compound?

The Law of Definite Proportions

300

How do you dilute a solution?

You add solvent to the solution. Most of the time the solvent is water.

300

What two equations or fractions do we use for the volume - mass relationship (to convert from volume to mass)?

1 mol = 22.4 Liters

and

1 mol = molar mass

400

If you have

50 grams of methane (CH₄),

50 grams of propane (C₃H₈),

50 grams of butane (C₄H₁₀),

50 grams of pentane (C₅H₁₀),

then which sample will have the most molecules?

50 grams of methane (CH₄)

400

Why does a balloon filled with helium gas float while a balloon filled with xenon gas will sink like a brick?

Helium has a low molar mass which makes it lighter than air, but xenon has a very high molar mass which makes it a very heavy gas.

400

If a bottle of hydrogen peroxide says that it is 3% hydrogen peroxide, then what is the percent composition of the bottle?

3% Hydrogen Peroxide

97% Water

400

If you make two solutions by dissolving 50 grams of salt (NaCl) in one liter of water, and 50 grams of sugar (C₁₂H₂₂O₁₁) in another liter of water, then the sugar solution would be less concentrated. WHY?

Sugar has a greater molar mass than salt so 50 grams of sugar has less moles than 50 grams of salt.

400

What is the formula for the ideal gas law?

PV=nRT

500

Why does one mole of salt (NaCl) take up less then half of the volume as one mole of sugar (C₁₂H₂₂O₁₁)?

Salt particles are a lot smaller than sugar particles and salt is more dense then sugar.