Lecture 11

Question 1

ΔHrxn gas

Answer 1

1 atm, ideal gas (not interacting)

Question 2

ΔHrxn liquid

Answer 2

1M concentration

Question 3

ΔHrxn pure substance

Answer 3

Standard state at 1 atm and 25 degrees C

Question 4

What does putting NaCl into water do?

Answer 4

Aqueous solution with Na + (aq) + Cl - (aq)

Question 5

Soluble

Answer 5

When a solid dissolves in a solvent

Question 6

Miscible

Answer 6

When one liquid “dissolves” into another liquid

Question 7

Nonelefcrolytes

Answer 7

Retain their molecular structure when dissolved in water

Question 8

Gases: temp and solubility

Answer 8

Temp (up), solubility (down)

Question 9

Solids (Temp and solubility)

Answer 9

Temp (up), solubility (up)

Question 10

Concentration

Answer 10

Relative amount of solute and solvent in the solution

Question 11

Dilute

Answer 11

Relatively small amount of solute

Question 12

Concentrated

Answer 12

Relatively large amount of solute

Question 13

Saturated

Answer 13

Largest amount of solute possible in that solvent at that temperature

Question 14

Supersaturated solution

Answer 14

Contains more solute than the maximum expected in that solvent at that tempersture (unstable)

Question 15

Molarity (concentration)

Answer 15

mol of solute/ L of solution

Question 16

Solubility

Answer 16

Maximum amount of solute that can be added to solvent to achieve a stable, equilibrium solution

Question 17

Molality units

Answer 17

Moles of solute/ kg of solvent

Question 18

Molarity units

Answer 18

Moles solute/ volume solution

Question 19

Mass percentage (parts per millions)

Answer 19

Grams solute/ grams solvents

Question 20

Mole fraction

Answer 20

Moles of solute/moles of solution

Question 21

UV-VIS Spectroscopy

Answer 21

Measurement of absorption of UV or visible light by a substance

Question 22

Visible regions

Answer 22

UV: 190-400 nm
Visible: 400-700nm

Question 23

Releasing light

Answer 23

When excited electrons fall back to normal energy levels

Question 24

Water is transparent above

Answer 24

190 nm

Question 25

Beer-Lambert Law

Answer 25

A = εbl

ε - extinction coefficient (molar absorptivity)
c - concentration (usually M)
l - path length (often 1cm)

Question 26

Process to “release” excess energy

Answer 26

Fluorescence, phosphorescence, heat, photochemistry

Question 27

Standard solution

Answer 27

Solutions with unknown concentrations

Question 28

Calibration curve

Answer 28

A general method for determining the concentration of a substance in an unknown sample by comparing the unknown to a set of standard samples of known concentration

Question 29

The higher the pressure,

Answer 29

The higher the solubility

Question 30

UV-VIS bands are

Answer 30

Broad bc of different vibrational, rotational, translational states

Question 31

Electrolyte be non electrolyte

Answer 31

Electrolyte: aqueous solution conducts electric current well
Non: apps solution does not conduct electric current