Percent Composition and Moles

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

Find the percent composition of N₂S₂.

• N: 69.6%  S: 30.4%

• N:36% S: 75.6%

• N: 96.6% S: 3.4%

• N: 30.4% S: 69.6%

What is the mass percentage of Carbon in Carbon dioxide (CO₂)?

• 27.27%

• 42.86%

• 72.73%

• 72.72%

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

• Mg₄N₃

• MgN₂

• Mg₃N₂ 

• MgN

A student calculated the number of moles of methane (CH4) present in a 100g sample of a gaseous mixture. If the student determined that there’s 0.6 moles of methane present in the sample, what is the percent composition of methane in the sample?

• .096%

• 9.6%

• .9%

• 90%

What is the percent composition by mass of sulfur (S) in the compound MgSO₄?

• 20.22%

• 19.85%

• 26.64%

• 28.64%

Find the percent composition of Cu₂S?

• %Cu= 67.987 %S= 32.013

• %Cu= 79.854   %S= 20.145

• %Cu= 35.946   %S= 64.054

What is the percent composition of hydrogen in water (H2O)?

• A) 11.19%

• B) 88.81%

• C) 33.33%

• D) 66.67%

Calculate the number of moles in 50 grams of water (H2O).

• A) 2.78 moles

• B) 1.39 moles

• C) 0.56 moles

• D) 0.28 moles

A sample contains 40% carbon and 60% oxygen by mass. What is the empirical formula of the compound?

• A) CO

• B) CO2

• C) C2O

• D) C2O3