Chemistry 32S Exam Flashcards
What does the mass number of an atom tell us?
The mass number of an atom tells us how many protons and neutrons there are.
Define the pressure inside a closed container in terms of the kinetic theory
A particle colliding with the interior walls of the container
What is the bond angle of linear or AB2?
180°
What volume of 0.196 M of LiOH is required to neutralize 27cm3 of 0.413M H2SO4? (Worth 3 marks)
1.) write the balanced chemical equation
(1/2) 2LiOH + H2SO4 —> LiSO4 + 2H2O
2.) n = CV
(1/2) n = 0.0113 mol (1/2)
(1/2) 2 to 1 ratio moles of LiOH = 0.02255mol (1/2)
(1/2) 115 ml of LiOH required
Describe how to prepare a 500.0 ml solution of 0.520 M of NaBr using 12.9g of NaBr. (4)
- ) Add 12.9g of NaBr to a 500ml volumetric flask
- ) Add distilled water and dissolve NaBr.
- ) Top up with distilled water until bottom of meniscus is at the etch mark
- ) Cap, invert several times to mix thoroughly
What does the atomic mass of an atom tell us?
The atomic mass of an atom tells us the average mass of the atom’s mass number
What is the bond angle of a linear or AB(E)small n?
N/A
The relative rates of diffusion of two gasses at constant temperature depend only on this factor:
Relative masses of molecules
State what happens according to kinetic theory to cause a drink to get squished when the juice inside is sucked out through the straw.(2)
Interior particles are removed, reducing interior pressure.
Atmospheric pressure is greater, crushing it.
What is the bond angle of trigonal planar or AB3?
120° —> 360/3
What is the melting point trend in halogens as you go down the periodic table?
The melting point trend in halogens as you go down the periodic table is that it increases
If 6 mol of H2 is reacted with 4 mol of O2 to form water, the limiting reactant is:
Hydrogen
As the temperature of the gas in a sealed glass container increases, what happens to the pressure?
The pressure of the gas will increase linearly
What is the bond angle of angular or AB2E?
120° > x > 109.5°
Define the temperature of a substance in terms of the kinetic theory
Average kinetic energy of the particles
Compare the boiling points of C2H6 and C3H8.
C2H6 and C3H8 are both polar. C2H6 has a lower boiling point because C3H8 is much heavier, it has more molar mass than C2H6. The higher the molar mass, the more energy you need to boil
The mass of 1.30*10 to the 23 molecules of water is:
44.8g
What is the bond angle of tetrahedral or AB4?
109.5°
What is the bond angle of pyramidal or AB3E?
109.5° > x > 90°
What condition must be fulfilled in order for boiling to occur?
Pressure of evaporated vapour must equal the atmospheric pressure
This is the number of molecules in 3.3*10 to the 14 mol of H2O
2.0*10 to the 32 molecules