Moles, % Comp, EF/MF Quiz 2021

Which of the following statements regarding the mole is INCORRECT?

• A mole is a unit of quantity 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

What is the molar mass of PbSO₄?

• 303.27 g/mol

• 255.27 g/mol

• 163.87 g/mol

• 372.27 g/mol

Shivani measures out 6.0 moles of epsom salt (MgSO₄) to put in her bath. How many grams of MgSO₄ went in the bath?

• 3.6 x 10²⁴ g

• 720 g

• 0.050 g

• 340 g

Tags

NGSS.HS-PS1-7

How many molecules are there in 31.8 moles of water?

• 5.28 x 10^-23 molecules
• 1.91 x 10²⁵ molecules
• 5.28x 10-²⁵
• 1.91 x 10²²

What is the mass of 1.2 x 10²⁴ atoms of C?

• 2.0 grams

• 24 grams

• 0.17 grams

• 1.4 x 10²⁵ grams

Tags

CCSS.8.EE.A.3

Calculate the number of atoms in 0.0340 g Zn.

• 5.20 x 10^-4 atoms Zn

• 3.13 x 10²³ atoms Zn

• 3.13 x 10²⁰ atoms Zn

• 2.05 x 10²² atoms Zn

Tags

CCSS.8.EE.A.3

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

• 1.26 moles

• 0.8 moles

• 7,670 moles

• 1.63 x 10^-22 moles

Tags

NGSS.HS-PS1-7

What is the equation for calculating percent composition?

• mass of element/mass of compound = x 100
• mass of compound/mass of element = x 100 
• total mass/molar mass = x 100 
• molar mass/molar mass = x 100 

What is the percent composition by mass of magnesium in the compound MgSO₄

• 20%

• 27%

• 46%

• 53%

What is the empirical formula for the following molecular formula: C₆H₁₄

• C₆H₁₄
• C₃H₇
• CH₂
• CH₃