Chapter 7 Moles

Which of the following statements regarding the mole is incorrect?

• A mole is a counting unit equal to 6.02 x 1023 particles.

• The number of particles in a mole is known as Avogadro’s number.

• A mole of particles of an element is numerically equal to the atomic mass of the element.

• none of the above

How many atoms of iodine are in a mole of iodine?

• 53
• 63.55g
• 126.9
• 6.02 x 10²³

What is the molar mass of NaCl?

• 58.45g/mol
• 28g/mol
• 12g/mol
• 6.02 x 10²³

What is the percent by mass of magnesium in MgO?

• 20%
• 40%
• 50%
• 60%

How many moles are 98.3 grams of aluminum hydroxide, Al(OH)₃?

• 1.26 moles
• 0.8 moles
• 7,673.4 moles
• 150 moles

Tags

NGSS.HS-PS1-7

A compound consists of 72.2% magnesium(Mg) and 27.8% nitrogen(N) by mass. What is the empirical formula?

• Mg₄N₃
• MgN₂
• Mg₃N₂ 
• MgN

Convert 25 g of NaBr to molecules

• 102.96 molecules

• 0.24 molecules

• 1.45x10²³ molecules

• 2.34 x 10²⁰molecules

Tags

NGSS.HS-PS1-7

The empirical formula for hydrocarbon A is C₂H₇O. If the molar mass of the hydrocarbon is 141 g/mol, determine the molecular formula for this hydrocarbon.

• C₂H₇O

• C₄H₁₄O₂

• C₆H₂₁O₃

• C₈H₂₈O₄

(0903) Determine how many grams are in 0.36 moles of CCl₄ (molar mass = 153.82 g/mol)

• 150 g

• 55 g

• 0.0023 g

• 2.2 g

A formula with the lowest whole # ratio of elements in a compound is called

• Molecular Formula
• Chemical Formula
• Empirical Formula 
• Distance Formula