Percent by mass

John is studying the composition of water for his science project. He needs to know the percent by mass of Oxygen in a water molecule (H₂O). Can you help him?

• 33 %

• 88.9%

• 11.1%

• 50%

Tags

NGSS.HS-ESS2-5

What is the percent by mass of Carbon in sugar C₁₂H₂₂O₁₁ ?

• 144.0

• 42.1

• 12.01

• 342.0

What is the percent by mass of Hydrogen in sugar C₁₂H₂₂O₁₁?

• 42.1

• 22.0

• 342.0

• 6.43

What would the percent by mass be of Oxygen in a compound that has a formula of C₁₀H₁₈O ?

• 154.0

• 77.9

• 10.4

• 11.7

A manufacturer advertises a new synthesis reaction for methane with a percent yield of 110%. Comment on this claim.

• That is an awesome return as most can not even get 100%

• It is false because you can not get more than 100% it must have contaminants in the product.

• It could be possible if they did not loose any product in the process

• It is unlikely because in the process product is often lost along the way making hitting 110% difficult but not impossible.

Tags

NGSS.HS-PS1-6

NGSS.HS-PS1-7

What is the concentration, in percent by mass, of 0.62 g of solute in 45.0 g of solution?

• 0.014 %

• 1.4 %

• 0.13%

Determine the number of oxygen atoms in Al(OH)₃

• 1

• 2

• 3

• 4

Tags

NGSS.MS-PS1-1

C₃H₅(NO₃)₃ Identify the correct number of atoms

• C = 3, H = 5, N = 3, O = 9

• C = 3, H = 5, N = 1, O = 9

• C = 9, H = 15, N = 3, O = 9

• C = 9, H = 15, N = 1, O = 3

Tags

NGSS.MS-PS1-1

Calculate the molar mass of CuBr₂

• 143.45 g/mol

• 223.35 g/mol

• 287.30 g/mol

• 307.90 g/mol

What is the percent by mass of Cu in CuBr₂?

• 50%

• 71.6%

• 28.4%

• 44.3%