AP Chem Midterm Review Questions

Fun fact: Rice absorbs moisture even faster than salt. You're familiar with the lifesaver of putting your water-damaged phone in a bag of uncooked rice? It's the same concept. By adding just a few grains of rice to your salt shaker, restaurants can guarantee that your salt will pour with ease. How does the percent by mass of Na⁺ compare in the two shakers?

NO Calculator:)

• The shaker WITHOUT rice has a larger percent by mass Na⁺. A larger part of the whole 10.0g sample is due to the mass of Na_⁺.

• The shaker WITH rice has a larger percent by mass Na⁺. A larger part of the whole 10.0g sample is due to the mass of Na_⁺.

• The shakers have EQUAL percent by mass Na⁺. They have the same total mass and therefore the same percent by mass Na⁺.

Tags

NGSS.HS-PS1-3

One salt shaker is pure NaCl. The second salt shaker is a mixture of NaCl and Na₂O. How does the percent by mass of Na⁺ compare in the two shakers?

NOTE: Do not eat Na₂O :)

NO Calculator:)

• The shaker WITHOUT Na₂O has a larger percent by mass Na⁺. A larger part of the whole 10.0g sample is due to the mass of Na^₊.

• The shaker WITH Na₂O has a larger percent by mass Na⁺. A larger part of the whole 10.0g sample is due to the mass of Na^₊.

• The shakers have EQUAL percent by mass Na⁺. They have the same total mass and therefore the same percent by mass Na⁺.

Tags

NGSS.HS-PS1-7

When a 2.04 g sample of an unknown hydrate of magnesium carbonate, MgCO₃ · xH₂O(s), is heated, H₂O (molar mass 18 g) is driven off. The mass of the anhydrous MgCO₃(s) (molar mass 84 g) that remains is 1.68 g. The value of x in the hydrate is

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• 1

  The sample is a monohydrate

  MgCO₃ · H₂O

• 2

  The sample is a dihydrate

  MgCO₃ · 2H₂O

• 5

  The sample is a pentahydrate

  MgCO₃ · 5H₂O

• 10

  The sample is a decahydrate

  MgCO₃ · 10H₂O

Tags

NGSS.HS-PS1-7

A student prepares a solution of potassium permanganate, KMnO₄, (molar mass 160g/mol) as the titrant for a REDOX titration. To do so, they dissolve 32.0g in enough water to make 400.mL of solution. What is the molar concentration of the solution?

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• 0.500M

• 0.200M

• 0.100M

• 0.700M

Tags

NGSS.HS-PS1-5

A mixture of O₂(g) and H₂(g) is placed in a container, as shown. A reaction occurs, forming H₂O(g). Which of the following best represents the contents of the box after the reaction has proceeded as completely as possible?

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• 
• 
• 
• 

Tags

NGSS.HS-PS1-4

NGSS.HS-PS1-7

Give the net ionic equation for the reaction

Pb(NO₃)₂ + Li₂SO₄ → PbSO₄ + 2LiNO₃

I) Pb²⁺(aq) + 2(NO₃)^1-(aq) + 2Li¹⁺(aq) + SO₄^2-(aq) → PbSO₄(s) + 2LiNO₃(s)

II) 2Li¹⁺(aq) + 2(NO₃)^1-(aq) → 2LiNO₃(s)

III) Pb²⁺(aq) + SO₄^2-(aq) → PbSO₄(s)

IV) Li¹⁺(aq) + (NO₃)^1-(aq) → LiNO₃(s)

NO Calculator :)

• I)

• II)

• III)

• IV)

Tags

NGSS.HS-PS1-2

The diagram shown represents an initial mixture of H₂(g), I₂(g) and HI(g) in a 1.0L container at 298K. The gases react and reach equilibrium according to the equation below. To reach equilibrium, what will happen to the initial mixture?

H₂(g)+ I₂(g) ⇄ 2HI(g) K = 9 at 298K

• The initial mixture will shift to form more product.

• The initial mixture is at equilibrium.

• The initial mixture will shift to form more reactant.

• This is not an equilibrium reaction.

Tags

NGSS.HS-PS1-5

The diagram shown represents an initial mixture of H₂(g), I₂(g) and HI(g) in a 1.0L container at 298K. The gases react and reach equilibrium according to the equation below. To reach equilibrium, what will happen to the initial mixture?

H₂(g)+ I₂(g) ⇄ 2HI(g) K = 9 at 298K

• The initial mixture will shift to form more product.

• The initial mixture is at equilibrium.

• The initial mixture will shift to form more reactant.

• This is not an equilibrium reaction.

The diagram shown represents an initial mixture of H₂(g), I₂(g) and HI(g) in a 1.0L container at 298K. The gases react and reach equilibrium according to the equation below. To reach equilibrium, what will happen to the initial mixture?

H₂(g)+ I₂(g) ⇄ 2HI(g) K = 9 at 298K

• The initial mixture will shift to form more product.

• The initial mixture is at equilibrium.

• The initial mixture will shift to form more reactant.

• This is not an equilibrium reaction.

Tags

NGSS.HS-PS1-5

Cu²⁺(aq) + Zn(s) → Cu(s) + Zn²⁺(aq)

E⁰_cell= +1.10V

Which of the following correctly describes the equilibrium constant, K, and the standard free energy change, ΔG°, for this reaction?

• K is greater than 1

  ΔG° is positive

• K is greater than 1

  ΔG° is negative

• K is less than 1

  ΔG° is positive

• K is less than 1

  ΔG° is negtaive

Tags

NGSS.HS-PS1-4