AP Chemistry Unit

According to the following reaction, how many grams of ammonia will be formed upon the complete reactions of 15.8 grams of nitrogen gas with excess hydrogen gas?

• 9.60 grams ammonia

• 19.2 grams ammonia

• 38.4 grams ammonia

• 4.80 grams ammonia

A sample of a hydrate of Na₂CO₃ with a mass of 550 grams was heated until all the water was removed. The sample was then weighed and found to have a mass of 300 grams. What is the formula for the hydrate?

• Na₂CO₃ ⋅ 4H₂O

• Na₂CO₃ ⋅ 10H₂O

• Na₂CO₃ ⋅ 3H₂O

• Na₂CO₃ ⋅ 5H₂O

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-7

Al₂O₃(l) → Al(s) + O₂(g)

Approximately how many liters of oxygen gas will be evolved at STP, if 25.68 grams of alumina decomposes?

• 22.4 L

• 8.46 L

• 5.64 L

• 11.2 L

The mass spectrum represented above is most consistent with which of the following elements?

• Nb

• Zr

• Y

• Mo

An element consists of 94.93% of an isotope with mass 31.97 u, 0.76% of an isotope with mass 32.97 u, 4.29% of an isotope with mass 33.97 u, and 0.02% of an isotope with mass 35.97 u. Calculate the average atomic mass, and identify the element.

• 32.06,S

• 32.07,P

• 3206,S

• 3207,P

The element boron (B) has two naturally occurring isotopes, ¹⁰B and ¹¹B, with an average atomic mass of 10.812 u. Boron is 80.2 % ¹¹B, and the atomic mass of ¹¹B is 11.009 u. Calculate the mass of ¹⁰B.

• 10.5 u

• 11.01 u

• 10.01 u

• 10.8 u

The molecule drawn above has the same empirical formula as another compound "X" with a molar mass of 265.1.

Determine the molecular formula of compound "X".

• C₂H₃O

• C₄H₆O₂

• C₁₂H₁₈O₆

• C₈H₁₂O₄

A compound contains only carbon, hydrogen, and oxygen. Combustion of 15.36 mg of the compound yields 9.56 mg CO₂ and 1.80 mg H₂O. The molar mass of the compound is 120.2 g/mol. What is the molecular formula of the compound?

• CHO₄

• C₂H₂O6

• C₃H₁₂O₃

• C₃H₃O12

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-7

A compound containing only calcium, oxygen, and carbon is 45.3% Ca and 20.5% O by mass; the molar mass is 525 g/mol. What is the molecular formula of the compound?

• Ca₂O₂C_5

• CaOC_2.5

• Ca₆O₆C₁₅

• Ca₂O₂C₆

A sample of a compound is a mixture of FNO₃ and ClNO₃. The compound is analyzed in a laboratory, and the results are recorded in the table above. Calculate the mole ratio of Cl to F in the compound?

• 2:1

• 1:2

• 3:2

• 2:3