Inv. 8. Exp.3. Practice Quiz Team Competition

Find the molar mass of KCl ?

• 58.44 g/mol
• 89.10 g/mol
• 35.45 g/mol
• 74.55 g/mol

Find the number of mol in 5 g. Of NaCl₂ ?

• 0.0532 mol
• 0.0756 mol
• 0.1000 mol
• 0.0254 mol

A common fertilizer used in agriculture is NH₂NO. What is the approximate percent composition of nitrogen, hydrogen, and oxygen?

• Nitrogen: 70%, Hydrogen: 15%, Oxygen: 15%
• Nitrogen: 60%, Hydrogen: 5%, Oxygen: 35%
• Nitrogen: 50%, Hydrogen: 10%, Oxygen: 40%
• nitrogen : 61%

  hydrogen : 4 %

  oxygen: 35%

Copper (III) oxide (Cu₂O₃), also known as rust, is a common compound found in nature. What mass of pure copper can be extracted from 100 g of Copper Oxide?

• 71.52 g

• 50.0 g
• 39.0 g
• 72.58 g

Cobalt(II) chloride hexahydrate (CoCl₂ · 6H₂O) is a pink crystalline compound. Calculate the percentage by mass of water present in this hydrated compound, rounded to the nearest whole number.

• 60
• 30
• 75
• 45

From the combustion analysis, determine the mole ratio of the elements in the sample.

60% Carbon (C)

13.3% Hydrogen (H)

26.7% Oxygen (O)

• 5 mol C, 13 mol H, 1.6 mol O

• 1 mol C, 2 mol H, 1 mol O

• 4 mol C, 10 mol H, 1 mol O

• 7 mol C, 3 mol H, 1 mol O

Given a mole ratio of 3 moles of Carbon, 8 moles of Hydrogen, and 1 mole of Oxygen, what is the empirical formula?

• C₃H₈O

• C₃H₇O₂

• C₄H₁₀O

• C₂H₆O

Given: Sample W2112, molar mass 51.0 g/mol, empirical formula C₂N₃H. Determine the molecular formula.

• C₁N₃H₂

• C₂N₃H

• C₂N₄H

• C₃N₂H₂