CHEM 280 MIDTERM EXAM AND CHEM 280 FINAL

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CHEM 280 MIDTERM EXAM AND CHEM 280 FINAL

EXAM PRACTICE TESTS WITH 300 REAL EXAM

QUESTIONS WITH CORRECT DETAILED ANSWERS

(EXPERT VERIFIED SOLUTIONS T O ALL CALC

PROBLEMS AND FORMULAS SHOWN)

Chem 280 midterm exam practice qs These are all the formulas you need to know to succeed!

• Molarity = Moles / Volume
• Moles = Mass / Molar Mass

Moles 9 is also 9 x 10^-3 Milli Moles

• pH = -log x Cation
• H3O x OH = 1 x 10^-14
• Total Mass = Solute + Solvent
• Mass Percent = Solvent Mass / Total Mass x 100
• Total Pressure - Partial Pressures = Remaining Pressure
• P1 x V1 / T1 = P2 x V2 / T2
• Molar Mass = G/Mol
• Specific Heat = Energy / (Mass x Temp)

11. V1 / T1 = V2 / T2

• M1 x V1 = M2 x V2
• Percent Yield = Actual Yield / Theoretical Yield

What is the molarity of a solution prepared by dissolving 10.7 g NaI in 0.250 L?

0.286 Molarity (M) = Number of Moles of solute / Liters solution

• How many moles represent 10.7 g of NaI?

NaI = 22.9 g/mol + 126.90 g/mol = 149.8 g/mol 1 / 4

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Exactly 17.0 mL of a H2SO4 solution was required to neutralize 45.0 mL of 0.235 M NaOH. What was the concentration of the H2SO4 solution?

Given: H2SO4 (aq) + 2NaOH (aq) → 2H2O (l) + Na2SO4 (aq)

0.311 M

Molarity = Concentration

H2SO4 (aq) + 2NaOH (aq) → 1:2 (NaOH 2mol당 H2So4 1mol)

In the following reaction:

HCO3- (aq) + H2O (aq) → H2CO3 (aq) + OH- (aq) H2O is an acid and OH- is its conjugate base.

How many carbon atoms are in the formula Al2(CO3)3?

• 6
• 3
• 1
• 9none of the above - ANSWER-b. 3 2 / 4

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A fictional element has two naturally occurring isotopes with the natural

abundances shown here:

ISOTOPE

18 40.0%

ABUNDANCE

20 60.0% Which statement is TRUE for this element?

• The atomic mass would be less than 18.
• The atomic mass would be exactly 19.
• The atomic mass would be greater than 20.
• The atomic mass would be closer to 20 than to 18.
• The atomic mass would be closer to 18 than to 20. - ANSWER-d. The atomic

mass would be closer to 20 than to 18.

Which of the following is a molecular compound?

• barium sulfide
• calcium acetate
• potassium hydroxide
• nitrogen monoxide
• none of the above - ANSWER-d. nitrogen monoxide
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pg. 4 Which statement reflects the results of Rutherford's gold foil experiments?

• Almost all of the alpha particles sputtered gold atoms off of the surface of the

foil.

• Almost all of the alpha particles were deflected back in the direction from which

they came.

• Almost all of the alpha particles passed directly through the foil.
• Almost all of the alpha particles were deflected while passing through the foil.
• none of the above - ANSWER-c. Almost all of the alpha particles passed directly

through the foil.

Which of the following is NOT a correct name, symbol combination?

• iron, Fe
• phosphorus, P
• beryllium, Be
• manganese, Mg
• silicon, Si - ANSWER-d. manganese, Mg

Which statement below accurately describes the contributions of Thomson?

• created the modern periodic table
• proposed the modern Atomic Theory
• discovered the existence of electrons
• ancient Greek philosopher who proposed that matter was continuous
• none of the above - ANSWER-c. discovered the existence of electrons
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