Unit 4: Gases
How does KMT define pressure?
Rank the 3 different IMFS based on their strength (weakest to strongest).
1.) London dispersion forces
2.) Dipole-dipole forces
3.) Hydrogen bonding
What three things are required for a reaction to occur?
1.) Particles must collide
2.) with enough energy
3.) and in proper orientation
Define each variable AND their units in the Molarity equation: M=n/V
M = Molarity (M)
n = moles (mol)
V = volume (L)
In which process does the system GAIN energy (endothermic or exothermic)?
Endothermic
Convert 889 mmHg to atm.
1 atm = 760 torr = 101.3 kPa = 760 mmHg
1.170 atm
Name the following molecule:
S3F6
Trisulfur hexafluoride
In an exothermic reaction, are the reactants or the products at a higher potential energy?
Reactants
Find the Molarity of a 850 mL solution containing 42.6 g of CaCl2.
(MM of CaCl2 = 110.98 g/mol)
0.45 M CaCl2
If the same amount of energy is added to both, will a substance with a high or low specific heat reach a higher temperature? Explain your answer.
Low specific heat because it requires less energy to change its temperature
What is the temperature (in °C) if a gas at 990 mmHg and 32°C is compressed to 740 mmHg?
P1/T1 = P2/T2
-45°C (228 K)
Draw the Lewis structure for SiO2.
Is it polar or nonpolar??
(Ms. Tran will draw it!)
Nonpolar
DOUBLE JEOPARDY!
What is Avogadro's number?
6.02 x 1023 !!
Find the volume (in mL) of a 1.45 M KCl solution containing 0.283 mol of KCl.
195 mL of KCl
Determine the mass of iron that has absorbed 3020 J of energy and increased from 20°C to 83°C. The specific heat capacity of iron is 0.449 J/g°C.
106.763 g of iron
What is the volume (in mL) of a gas containing 2.32 g of CO2 at 28°C and 1.8 atm?
(Molar Mass of CO2 = 44.009 g/mol)
723 mL of CO2
For SO2 and CCl4,
- Draw their Lewis structures
- Determine their VSEPR shape
- Determine its molecular polarity
- Identify the IMFs
SO2: bent; polar; LDF & DD
CCl4: tetrahedral; nonpolar; LDF
How does adding a catalyst speed up the rate of a reaction?
Adding a catalyst offers another pathway with a LOWER activation energy
How many grams of AlCl3 are made when 400 mL of 1.5 M HCl reacts with excess Al?
2 Al + 6 HCl → 2 AlCl3 + 3 H2
26.668 g of AlCl3
A 23.0 g sample of lead initially at 27°C was given 83.2 J of energy. The specific heat capacity for lead is 0.128 J/g°C. Calculate the FINAL temperature of the lead sample.
55.26°C
If 10.3 g of magnesium nitride is treated with water, what volume of ammonia gas would be collected at 20°C and 0.989 atm?
Mg3N2 + 3 H2O --> 3 MgO + 2 NH3
(Molar Mass of Mg3N2 = 100.9494 g/mol)
4.961 L of NH3
Out of the following molecules, which would have the highest melting point? Explain.
CO2, NH3, CH4, SO2
NH3 (It has hydrogen bonding!)
If I wanted to increase the rate of a reaction by manipulating volume, would I have to increase the volume or decrease it? Explain your answer.
Decrease the volume
There will be less space for the particles to move around, therefore increasing the frequency of effective collisions
How many Liters of 2.3 M AgNO3 are needed to react fully with 650 mL of 1.3 M Na3PO4?
3 AgNO3 + 1 Na3PO4 --> 1 Ag3PO4 + 3 NaNO3
1.102 Liters of AgNO3
An unknown mass sample of copper heated to 94°C was dropped into 130.0 mL of water initially at 25°C. The temperature of the water increased by 10.5°C. Copper has a specific heat of 0.385 J/g°C. What is the mass of the copper sample?
253.576 g of copper