Most Challenging AP Chem

An impure sample of NaCl contains 20% Na, and the other impurities do not contain Na. How much of the sample contains pure NaCl? Use the following molar masses: Na - 23, NaCl - 58

• 50%

• 20%

• 110%

• 35%

What is the molecular shape of BrF₃^-

• linear

• bent

• seesaw

• t-shaped

If a sample of x grams of Li₂O contains 40% Li (not accurate), then what would the percent of Li be for Li₂S of x grams?

• It would be less than 40% because S has a larger molar mass.

• It would be less than 40% because S is not a diatomic

• It would be greater than 40% because S has a smaller molar mass.

• It would be greater than 40% because S is just fat

Cu + HNO₃ → Cu(NO₃)₂ + NH₄NO₃ + H₂O

Which is Oxidized?

• Cu

• HNO₃

• NO_3

• H₂O

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which of the following is true according to the image above?

• Bond order on the top oxygen atom is 1.33

• Bond order on the top oxygen atom is 1

• Bond order on the bottom right oxygen atom is 2

• Bond order on the bottom right oxygen atom is 1.67

A student combines a solution of NaCl(aq) with a solution of AgNO₃(aq), and a precipitate forms.

Assume that 50.0mL of 1.0MNaCl(aq) and 50.0mL of 1.0MAgNO₃(aq) were combined. According to the balanced equation, if 50.0mL of 2.0MNaCl(aq) and 50.0mL of 1.0MAgNO₃(aq) were combined, the amount of precipitate formed would

• not change, because the amount of AgNO₃(aq) did not change

• not change, because all of the coefficients are 1

• double, because the amount of one of the reactants was doubled

• double, because all of the coefficients are 1

Tags

NGSS.HS-PS1-5

The table above shows the first ionization energy and atomic radius of several elements. Which of the following best helps to explain the deviation of the first ionization energy of oxygen from the overall trend?

• The atomic radius of oxygen is greater than the atomic radius of fluorine.

• The atomic radius of oxygen is less than the atomic radius of nitrogen.

• There is repulsion between paired electrons in oxygen’s 2p orbitals.

• There is attraction between paired electrons in oxygen’s 2p orbitals.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

What is the VSEPR shape of ClF₃?

• T-Shaped

• Trigonal Pyramidal

• Trigonal Planar

• Seesaw

Which species is being oxidized in the reaction below?

Cu(s) + 2 AgNO₃ (aq) → 2 Ag(s) + Cu(NO₃)₂ (aq)

• Cu(s)

• Ag(s)

• NO3 (aq)

• None of the above

Which of these is the oxidation number of H₂ gas?

• 0

• +1

• -1

• +2