Calculate the percent by mass of a solution containing 0.21 moles of c12h22o11 (gram-molecular mass = 342 g/mole) in 250 g of water.

28.728%

We are given;

Moles of the solute, C12H22O11 = 0.21 moles

Molar mass of C₁₂H₂₂O₁₁ = 342 g/mol

Mass of the solvent water = 250 g

We need to calculate the percent by mass of a solution

Mass = Number of moles × Molar mass

Therefore;

Mass of solute = 0.21 moles × 342 g/mol

                        = 71.82 g

% by mass = (Mass of solute ÷ mass of the solution)× 100

                = (71.82 g ÷ 250 g) × 100

                = 28.728%

Therefore, the percent by mass of the solution is 28.728%

the ozone layer acts as a filter for the shorter wavelength and highly hazardous ultraviolet radiation (uvr) from the sun, protecting life on earth from its potentially harmful effects. when the sky is clear, there is an inverse relationship between stratospheric ozone and solar uvr measured at the earth's surface.

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.