Mole Conversions and Percent Composition

What is the percent by mass of oxygen in Magnesium oxide?

• 20%

• 40%

• 50%

• 60%

Find the percent composition of Cu₂S?

• %Cu= 67.987 %S= 32.013
• %Cu= 79.854   %S= 20.145
• %Cu= 35.946   %S= 64.054

How many molecules are in 2.5 mol of NaCl?

• 1.51x10²³
• 146
• 4.15
• 1.51x10²⁴

Tags

NGSS.HS-PS1-7

How many atoms of carbon are in 6.00g of carbon?

• 1.20x10²⁴atoms C
• 6.02x10²³atoms C
• 3.01x10²³atoms C
• 1.50x10²³atoms C

Tags

NGSS.HS-PS1-7

How many grams are in 1.2 x 10²⁴ molecules of Carbon monoxide?

• 28 grams

• 56 grams

• 6.02 grams

• 1.2 grams

How many moles are in 3.01 x 10²² atoms of magnesium?

• 0.05 moles
• 1.81 x 10⁴⁶ moles
• 5.00 x 10²¹ moles
• 5 moles

What is the mass of 0.89 mol of CaCl₂?

• 111 grams
• 0.008 grams
• 98.9 grams
• none of the choices

Tags

NGSS.HS-PS1-7

Calculate the number of atoms in 0.0340 g Zn.

• 5.200 x 10^-4 atoms Zn
• 3.130 x 10²³ atoms Zn
• 3.130 x 10²⁰ atoms Zn
• 1 atom Zn

Tags

NGSS.HS-PS1-7

What is the percent by mass of fluorine in Calcium fluoride (molar mass = 78 g/mol)?

• 24%

• 49%

• 51%

• 65%

What is the percent composition by mass of sulfur in the compound MgSO₄ (molar mass = 120 g/mol)?

• 20%

• 27%

• 46%

• 53%