Quantitative Chemistry

How many molecules are present in 27.0 g of distilled water? (Avogadro’s constant = 6 x 10²³ mol^-1)

• 2.7 x 10²⁴

• 1.5

• 9.0 x 10²³

• 4.5

What amount of carbon dioxide (in mol) will be formed when 32.0 g of methane, CH₄, burnscompletely in oxygen?

• 1.0

• 2.0

• 4.0

• 8.0

How many oxygen atoms are present in 0.5 mole of pentahydrated copper(II) sulfate, CuSO₄.5H₂O?(Avogadro’s constant = 6 x 10²³ mol^-1)

• 2.5

• 4.5

• 3.0 x 10²³

• 2.7 x 10²⁴

What is the total number of atoms in 3.0 molecules of propanone, CH₃COCH₃?(Avogadro’s constant = 6 x 10²³ mol^-1)

• 10

• 30

• 1.8 x 10²⁴

• 1.8 x 10²⁵

Which contains the same number of ions as the value of Avogadro’s constant?

• 0.5 mol KBr

• 0.5 mol CaBr₂

• 1.0 mol CaO

• 1.0 mol K₂O

Tags

NGSS.HS-PS1-7

Which molecular formulas are possible for a compound which has an empirical formula of C₂H₄O?

I. CH₃CH₂OH

II. CH₃CH₂CH₂COOH

III. CH₃CH₂COOCH₃

• I & II only

• I and III only

• II and III only

• I,II and III

Which compound has the empirical formula with the largest mass?

• CH₄

• C₂H₄

• C₂H₆

• C₆H₆

What is the maximum mass, in grams, of magnesium oxide that can be formed when 4.8 g of magnesium reacts with oxygen?

• 4.8

• 8.0

• 11.2

• 12.8

Tags

NGSS.HS-PS1-7

Which is a correct statement about the molecular formula of a compound?

• It shows which functional groups are present in the molecule.

• It shows how all the atoms are bonded in a molecule.

• It is the simplest ratio of the atoms of different elements in the molecule.

• It is an integral multiple of the empirical formula.

98 g of a pure hydrocarbon contains 84 g of carbon. Which statements are correct?

I. The compound has an empirical formula of CH₂.

II. The compound has a molecular formula of C₇H₁₄.

III. Not enough information has been given to deduce the molecular formula.

• I & II only

• I & III only

• II & III only

• I,II & III

Tags

NGSS.HS-PS1-2