Structure 1.4 Review

Which of the following statements does not conform to the definition of a mole?

• 1 mole is the number of H₂O molecules in 18.02 g of H₂O

• 1 mole of Fe has a mass equal to the relative atomic mass of Fe in grams

• 1 mole of any substance contains 6.02 x 10²³ particles

• 1 mole is the number of H₂ molecules in 1.01 g of H₂

Which compound has the largest molar mass?

• FeSO₄

• K₂Cr₂O₇

• KMnO₄

• (NH₄)₃PO₄

Which of the following statements is true?

• The empirical formula shows only the type of each atom in a molecule

• The molecular formula is always the same as the empirical formula

• Organic molecules often have different empirical and molecular formulas

• The empirical formula is always greater than the molecular formula

Calculate the number of moles in 20.5 grams of sodium phosphate (Na₃PO₄)

• 0.125 mol

• 1.25 mol

• 12.5 mol

• 125 mol

Tags

NGSS.HS-PS1-7

Which of the following substances would have the lowest mass?

• 2.50 moles H₂O

• 2.50 moles CH₄

• 2.00 moles SO₂

• 2.00 moles CO₂

Tags

NGSS.HS-PS1-7

Refer to the following chemical equation: 2NO₂(g) → N₂O₄(g)

At the same temperature and pressure, 25.0 cm³ of nitrogen dioxide gas is completely converted into dinitrogen tetroxide gas. What will be the volume of N₂O₄ produced?

• 10.0 cm³

• 12.5 cm³

• 25.0 cm³

• 50.0 cm³

Tags

NGSS.HS-PS1-7

What is the percentage by mass of S in the compound sulfur dioxide SO₂?

• 25%

• 50%

• 75%

• 100%

What is the molecular formula of a compound with an empirical formula of CH₂O and a molar mass of 180.18 g/mol?

• CH₂O

• C₆H₆O₆

• C₆H₁₂O₆

• C₅H₁₀O₅

A sample containing 0.70 g of calcium nitrate, Ca(NO₃)_2, is dissolved in water to a volume of 200 cm³. What is the concentration of nitrate ions in this solution?

• 3.5 g dm^-3

• 7.0 g dm^-3

• 0.021 mol dm^-3

• 0.043 mol dm^-3

Tags

NGSS.HS-PS1-7

For which molecule is the empirical formula the same as the molecular formula?

• CH₃CH₂CH₂OH

• CH₃CH₂CH₂CH₃

• CH₃COOCH₂CH₃

• CH₃COOH