Basic Chemistry
Concepts
Concepts
Gases
Chemical Bonding
100
Define the term and explain the importance of SI units
SI units, also known as "base units", stands for International System of Units and are used in scientific communication to avoid confusion between different values.
100
State the Ideal gas law and give at least 2 assumptions.
PV = nRT
Assumes that gas molecules are independent and have no effect on other nearby atoms. The volume of each particle is negligible compared to the volume of the container. Each gas particle exhibits perfectly elastic collisions (no energy loss).
100
Name the 3 primary types of chemical bonding
Ionic bonding
Covalent bonding
Metallic bonding
200
Explain the concept of a mol (mole) in simple terms, including its important role in chemistry.
A mole is 6.022*1023 particles, and is a number in the same sense that a dozen (12) is a number. It represents a fixed number of items. Very useful in chemistry as the amount of atoms are huge!
200
A 10L gas cylinder is stored at room temperature (298.15K) at 1800psi. If the gas is transferred to a 6.0L cylinder, what temperature (in Celsius) would the cylinder be if the pressure remains constant?
Charles' Law!
V1/T1 = V2/T2
T2 = 178.89 K = -94.3*C
200
Based on the location of N on the periodic table, how many electrons would a single N atom need to gain/lose to satisfy the octet rule?
Gain 3 electrons.
300
The SI units for mass, length, volume, temperature, pressure, and an amount of a substance is what?
Mass - kg, kilogram
Length - m, meters
Volume - L, Litres
Temperature - K, Kelvin
Pressure - Pa, Pascals
Amount of substance, n - mol
300
1 mol of N2 and 1 mol of Ne are combined in a closed container at STP. What is the volume of the container?
V = 45.42 L
300
What feature of water molecules enables ionic compounds to dissolve in water and what term is used to describe this?
Water molecules are polar and are attracted to the positive and negative ions.
Solvation/hydration or solvated/hydrated
400
Define what a REDOX reaction is by explaining the name and include the movement of electrons.
REDOX reaction involves the transfer of electrons from one species to another in the form of two chemical steps, reduction and oxidation. Reduction is the gain of electrons and oxidation is the loss.
400
What is the molar mass of a gas if 142g of the gas occupies a volume of 45.1L at 301.55K and 0.946bar?
Using PV = nRT, Where n = m/M
Rearranging to solve for M:
M = mRT/PV = 83.4 g/mol
400
Draw the lewis structures for both of the following molecules:
CH4 and NF3
500
Determine whether each balanced chemical reaction on the board is a REDOX reaction. If yes, then identify the reducing agent and oxidizing agent.
a) Redox reaction. Reducing agent is Mg. Oxidizing agent is Fe2+.
b) Not a Redox reaction
500
You have two balloons, one filled with Kr and the other filled with Ne. The volume, pressure, and temperature of each balloon are the same. Which balloon contains the greatest amount of gas? Which balloon contains the most mass? How much denser is Kr than Ne (ratio of mm)?
As ideal gases, both contain the same amount of gas, in moles.
Kr contains the most mass because it has a higher molar mass.
The ratio of density of Kr to Ne is 4.153 (The ratio of their molar masses).
500
Explain the trend in the lattice energies of the alkaline earth metal oxides. Values given in kJ/mol:
MgO = -3795
CaO = -3414
SrO = -3217
BaO = -3029
As the size of the alkaline earth metal ion increases (descending the periodic table), so does the distance between the atoms. Therefore, the magnitude of the lattice energy decreases accordingly due to decreasing potential energy.