Mass Relationships

What is the sum of all coefficients when the following equation is balanced using the smallest possible whole numbers?

__ C₂H₂ + __O₂ → __CO₂ + __H₂O

• 5

• 7

• 11

• 13

How many molecules are present in a drop of ethanol, C2H5OH, of mass 2.3 × 10–3 g?

(L = 6.0 × 1023 mol–1)

• 3.0 × 10 ¹⁹

• 3.0 × 10²⁰

• 6.0 × 10²⁰

• 6.0 × 10²⁶

Which sample has the greatest mass?

• 1 mol of SO₂

• 2 mol of N₂O

• 2 mol of Ar

• 4 mol of NH₃

Tags

NGSS.HS-PS1-7

The relative molecular mass of a gas is 56 and its empirical formula is CH₂. What is the molecular formula of the gas?

• CH₂

• C₂H₄

• C₃H₆

• C₄H₈

Tags

NGSS.HS-PS1-7

What is the total number of hydrogen atoms in 1.0 mol of benzamide, C₆H₅CONH₂?

• 7

• 6.0 × 10²³

• 3.0 × 10²⁴

• 4.2 × 10²⁴

Tags

NGSS.HS-LS1-6

Which amount of the following compounds contains the least number of ions?

• 2 mol of NaOH

• 1 mol of NH₄Cl

• 2 mol of CaCl₂

• 1 mol of Al₂O₃

Which is both an empirical and a molecular formula?

• C₅H₁₂

• C₅H₁₀

• C₄H₈

• C₄H₁₀

6.0 mol of aluminium reacts with oxygen to form aluminium oxide. What is the amount of oxygen, in mol, needed for complete reaction?

4Al(s) + 3O₂(g) → 2Al₂O₃(s)

• 1.5

• 3.0

• 4.5

• 6.0

Tags

NGSS.HS-PS1-7

What is the total number of nitrogen atoms in two mol of NH₄NO₃?

• 4

• 6.02 × 10²³

• 1.20 × 10²⁴

• 2.41 × 10²⁴

Which sample has the greatest mass?

• 6.0 × 10²⁵ molecules of hydrogen

• 5.0 mol of neon atoms

• 1.2 × 10²⁴ atoms of silver

• 1.7 × 10² g of iron