Unit 1 - Matter and Energy - Honors

Question 1

Definition of Gay - Lussac’s Law of Combining Volumes (4)

Answer 1

1. When gases react
2. Volumes of gases
3. Are in simple, small whole-number ratios
4. If temperature and pressure are constant

Ex: H₂ (g) + CI₂ (g) = 2HCI (g)
1 vol. + 1 vol. = 2 vol.
1:1:2

Question 2

What’s the formula for the Ideal Gas Law?

Answer 2

PV = nRT

P = Pressure of Gas
V = Volume of Gas
n = Number of Moles in a Gas
R = Universal Gas Constant
T = Temperature in Kelvin of a Gas

Question 3

What is the Ideal Gas Law for? (2)

Answer 3

1. Combines Avogadro’s Law, Boyle’s Law and Charles’ Law
2. Gets the bigger picture on how gases behave under certain conditions

Question 4

How can you find the number of molecules in a gas?

Answer 4

You take PV = nRT and isolate n

n₁ = P₁V₁/RT ₁ n₂ = P₂V₂/RT₂

Question 5

How does
n₁ = P₁V₁ n₂ = P₂V₂
RT₁ RT₂
connect with Avogadro’s Hypothesis?

Answer 5

If P₁ = P₂, V₁ = V₂, R is ALWAYS the same, and T₁ = T₂, then n₁ = n₂

Question 6

Definition of Effusion (3)

Answer 6

1. Escape of gaseous molecules
2. Through a small hole
3. Into an evacuated space

Question 7

What are two things that the rate effusion depends on?

Answer 7

1. Temperature
2. Mass of Molecules

Question 8

What is Graham’s Law of Effusion? (2)

Answer 8

1. Under same temperature and pressure
2. Lighter molecules effuse faster

Question 9

How do you calculate Graham’s Law of Effusion? (2)

Answer 9

1. Identify molar masses (M₁ and M₂)
2. Take the quotient of the masses and square root it

Ex: Why do latex balloons filled with helium deflate?

He = 4g/mol
Air = 29g/mol
29/4 = 7.25
Square root of 7.25 = 2.69

Therefore, helium effuses 2.69x faster than air.

Question 10

Definition of Dalton’s Law of Partial Pressures

Answer 10

Total Pressure of a Mixture = Sum of Partial Pressures

(Assuming constant temperature and no interaction of gases)

Question 11

Dalton’s Law of Partial Pressure
1. You know ratio between PP
2. Know one value of moles for PP

Answer 11

Pₐ moles a
__ = __________
Pᵦ moles b

Question 12

Dalton’s Law of Partial Pressure
1. You know ratio between PP
2. Know one value of kPa for PP

Answer 12

Pₐ kPa a
___ = ________
Pᵦ kPa b

Question 13

Dalton’s Law of Partial Pressure
1. You know PP
2. Need to find TP

Answer 13

TP = PP1+PP2…..

Question 14

Dalton’s Law of Partial Pressure
1. If you know TP in kPa
2. If you know PP in percentages
3. Calculate PP

Answer 14

1. Convert Percentages to Decimals
2. Multiply Decimals by TP kPa

Question 15

What are Colloids? (6)

Answer 15

1. Heterogenous mixtures
2. Uniform to the naked eye
3. Due to Emulsifying Agents
4. Substance that is soluble in both liquids and stabilizes the mixture
5. Scatters Visible Light
6. Contains small undissolved particles
   Ex: Egg Yolk in Mayo

Question 16

What are the three different properties of liquids? (3)

Answer 16

1. Solution
2. Colloid
3. Suspension

Question 17

What is a Solution? (3)

Answer 17

1. Not filterable
2. Does not Separate Standing
3. Does Not Scatter Visible Light

Question 18

What is a Suspension? (3)

Answer 18

1. Cloudy/Opaque
2. Filterable
3. Separates While Standing