A glucose solution is prepared by dissolving 5.10 g of glucose, C6H12O6, in 110.5 g of water. What is the molality of the glucose solution? A) 0.283 m B) 0.000256 m C) 0.245 m D) 0.256 m

Question :- A glucose solution is prepared by dissolving 5.10 g of glucose, C6H12O6, in 110.5 g of `water. What is the molality of the glucose solution?
A) 0.283 m B) 0.000256 m C) 0.245 m D) 0.256 m

Answer :- 

 molality = number of moles of solute /mass of solvent in Kg 

The molar mass of glucose is   = 6*C + H*12+ O*6: 

                                                     =180.16 g/mol

So number of moles  of glucose = 5.10 / 180 = 0.0283 mol

These are present in 5.10g + 110.5g of solution = 115.6g

divide by 1000 to convert in Kg 

so 115.6 gram = 0.1156 Kg
 

molality = 0.0283 moles / 0.1156 kg
 

molality = 0.256                                            Answer  = D

Four of the five answers below are principal characteristics of all chordates. Select the exception. a. post-anal tail b. bony vertebra c. notochord d. dorsal nerve cord e. pharyngeal gill slits

Four of the five answers below are principal characteristics of all chordates. Select the exception.

a.    post-anal tail

b.    bony vertebra

c.    notochord

d.    dorsal nerve cord

e.    pharyngeal gill slits

Ans: b(  bony vertebra)

The first known primates were characterized as a. arboreal and nocturnal b. ground-dwelling and nocturnal c. arboreal and diurnal d. ground-dwelling and diurnal e. ground-dwelling and either nocturnal or diurnal

The first known primates were characterized as

a.   arboreal and nocturnal

b.   ground-dwelling and nocturnal

c.   arboreal and diurnal

d.   ground-dwelling and diurnal

e.   ground-dwelling and either nocturnal or diurnal

Ans:  arboreal and nocturnal

benzene to m- nitroacetophenone conversion,benzene to benzoic acid ,benzenesulphonic acid to aniline C6H5SO3H to C6H5NH2,phenol to acetophenone C6H5OH to C6H5COCH3

benzene to  m- nitroacetophenone conversion

benzene to benzoic acid

 

benzenesulphonic acid to aniline C6H5SO3H to C6H5NH2

phenol to acetophenone C6H5OH to C6H5COCH3

aniline to benzene , aniline to bromo benzene ,aniline to chloro benzene ,aniline to benzonitrile or cynobenzene ,aniline to Iodo benzene ,aniline to p-hydroxybenzene ,aniline to phenol conversion

aniline to benzene

 aniline to bromo benzene

aniline to chloro benzene 

aniline to benzonitrile or cynobenzene

aniline to Iodo benzene 

aniline to p-hydroxybenzene 

aniline to phenol