Exam 2 things to know

Question 1

7 Strong acids

Answer 1

HCl, HBr, HI, HClO3, HClO4, HNO3, H2SO4

Question 2

Strong bases

Answer 2

metal hydroxides of group 1A and 2A

Question 3

How do you find a minimum volume of a solution?
given: Molarity of a solution
mL of solution and Molarity of the solution
e.g. 2KI (aq) + Pb(NO3)2 -> 2KNO3 + PBI2
given: 1 M of KI
155.0 mL of 0.0560 M Lead (II) nitrate

Answer 3

Equation necessary: Molarity= moles of solute (mol) / Volume of solution (L)

1. convert mL to Liters (155.0 mL /1000 = 0.155 L)
2. multiply Liters and molarity to get mols of Lead (II) Nitrate (.155 L * .0560 M = .00868 mol)
3. find mols of Potassium Iodide. (1mol Pb(NO3)2 - 2 mols of KI. 2mols KI * .00868 mols of Pb(NO3)2 = .01736 mols of KI)
4. covert mols to Liters. (1 M of KI / .01736 mols off KI = .01736 L)

Question 4

How do you find an approximate volume of a solvent?
given: mL of a solution with given concentration
dilution with a given concentration
eg. 50 mL of a 4.6 M solution diluted to a concentration of 2.0 M

Answer 4

equation necessary: C1 V1= C2 V2

1. Multiply C1 and V1 (50 mL * 4.6 M = 230)
2. Divide by concentration of dilution (230 / 2.0 M = 115 mL)

Question 5

How to find the concentration of a particular element in a solution?
given: mL and concentration in an initial solution
Liters of dilution
eg. If 35.0 mL of .750 M stock solution of Na2CO3 are diluted to the volume of 0.500 L, what is the concentration of Na+ (aq)

Answer 5

necessary equation C1 V1 = C2 V2

1. write out the equation and balance (Na2CO3 -> 2Na + CO3)
2. convert mL to Liters ( 35.0 mL / 1000 = .035 L)
3. Find the Molarity of the dilution by multiply C1 and V1 and dividing by V2. (.035 L * .75 M / .5 L = .0525 M of 2Na+ CO3)
4. find Molarity of substance by multiplying its mols by the Molarity of the reaction from the balanced equation. (.0525 M * 2 mols of Na= .105 M)

Question 6

In endothermic reactions, heat is _____ and the sign of delta H is ____

Answer 6

absorbed, positive

Question 7

In exothermic reactions, heat is _____ and the sign of delta H is ____

Answer 7

released, negative

Question 8

How to find the amount of heat energy released?
given: grams of a substance in a reaction
eg. If 34.7 grams of water were produced, what amount of heat energy would be released
N2H4 + O2 -> N2 + 2H2O ; delta H = -622 kJ

Answer 8

1. Find mols of substance by using the molar mass of substance and mass of substance in reaction. ( (1 mol of H2O * 37.7 grams of H2O) / 18.018 g/mol of H2O = 1.926 mols of H2O)
2. find energy by multiplying the mols of the substance by the heat and dividing by the number of moles in the substance. ( (622 kJ * 1.926 mols of H2O) / 2 moles of H2O = 599 kJ

Question 9

find the energy of a substance released?

given: mols of substance and energy of a reaction

Answer 9

1. multiply mols of substance by energy

Question 10

Is energy emitted or absorbed?

from n=2 to n=5

Answer 10

absorbed, from closer to further

Question 11

Is energy emitted or absorbed?

from an orbit of radius 9.5 A to 4.5 A

Answer 11

emitted, from far to close

Question 12

Is energy emitted or absorbed?

from n=6 to n=1

Answer 12

emitted, from far to close