Unit 6 Post Assessment Remediation (PAR)

What is a chemical name of the compound CuS?

• copper(I) sulfide

• copper(I) sulfate

• copper(II) sulfide

• copper(II) sulfate

What is the chemical formula for ammonium sulfide?

• (NH₄)₂S

• (NH₄)₂SO₃

• (NH₄)₂SO₄

• (NH₄)₂S₂O₃

What is the chemical formula for lead(IV) oxide?

• PbO₂

• PbO₄

• Pb₂O

• Pb₄O

A compound has a molar mass of 90. grams per mole and the empirical formula CH₂O. What is the molecular formula of this compound?

• CH₂O

• C₂H₄O₂

• C₃H₆O₃

• C₄H₈O₄

What is the percent composition by mass of nitrogen in the compound N₂H₄ (gram-formula mass = 32 g/mol)?

• 13%

• 44%

• 88%

• 93%

What is the number of moles in a 78.8-gram sample of MgCO₃ (gram-formula mass = 84.3 g/mol)?

• 0.949 mol

• 0.935 mol

• 0.843 mo

• 1.070 mol

What is the gram-formula mass of Ca(OH)₂?

• 29 g/mol

• 54 g/mol

• 57 g/mol

• 74 g/mol

What is the approximate percent by mass of the water in the hydrated salt?

• 2.5%

• 12%

• 88%

• 98%

Tags

NGSS.HS-PS1-7

What is the total number of atoms of oxygen in the formula Al(ClO₃)₃ · 6H₂O?

• 6

• 9

• 10

• 15

Which formula is an empirical formula?

• N₂O₄

• NH₃

• C₃H₆

• P₄O₁₀