Question

The specific rotation, [α]_D, for (-)-malic acidis -27. What is the observed rotation for a solution of 0.75 g of (-)-malic acid in 10 mL of water in a sample tube having a pathlength of 10 cm?


The observed rotation of a solution of 1.4 g of a compound in 10 mL of water is -10degrees. If the pathlength is 10 cm, what is the specific rotation of the compound?


The specific rotation, [α]_D, for (-)-malic acidis -27. What is the observed rotation for a solution of 0.75 g of (-)-malic acid in 10 mL of water in a sample tube having a pathlength of 10 cm?


The observed rotation of a solution of 1.2 g of a compound in 10 mL of water is -5.3degrees. If the pathlength is 10 cm, what is the specific rotation of the compound?

The specific rotation, [α]_D, for (-)-malic acidis -27. What is the observed rotation for a solution of 1.2 g of (-)-malic acid in 10 mL of water in a sample tube having a pathlength of 10 cm?


The observed rotation of a solution of 1.3 g of a compound in 10 mL of water is +8.2degrees. If the pathlength is 10 cm, what is the specific rotation of the compound?

Answer 1

The specific rotation, [α]_D, for (-)-malic acidis -27. What is the observed rotation for a solution of 0.75 g of (-)-malic acid in 10 mL of water in a sample tube having a pathlength of 10 cm?

The Beer’s Law as follows:

[α]_D = α/ℓ ×c

Here [α]_D = -27,

l = 10 cm

1 .0 cm = 0.1 dm

10 cm = 1 dm

amount = 0.75 g and volume = 10 ml

c = concentration in g/mL

= 0.75 g/ 10 ml

= 0.075 g/ ml

[α]_D = α/ℓ ×c

α= [α]_D × ℓ × c

= -27*1*0.075

= -2.025 degree dm-g / ml

The observed rotation of a solution of 1.4 g of a compound in 10 mL of water is -10degrees. If the pathlength is 10 cm, what is the specific rotation of the compound?

The Beer’s Law as follows:

[α]_D = α/ℓ ×c

Here The observed rotation =-10degrees

l = 10 cm

1 .0 cm = 0.1 dm

10 cm = 1 dm

amount = 1.4 g and volume = 10 ml

c = concentration in g/mL

= 1.4g/ 10 ml

= 0.14 g/ ml

[α]_D = α/ℓ ×c

= -10degrees /1 *0.14

= -71.4

The specific rotation, [α]_D, for (-)-malic acidis -27. What is the observed rotation for a solution of 0.75 g of (-)-malic acid in 10 mL of water in a sample tube having a pathlength of 10 cm?

The Beer’s Law as follows:

[α]_D = α/ℓ ×c

Here [α]_D = -27,

l = 10 cm

1 .0 cm = 0.1 dm

10 cm = 1 dm

amount = 0.75 g and volume = 10 ml

c = concentration in g/mL

= 0.75 g/ 10 ml

= 0.075 g/ ml

[α]_D = α/ℓ ×c

α= [α]_D × ℓ × c

= -27*1*0.075

= -2.025 degree dm-g / ml

The observed rotation of a solution of 1.2 g of a compound in 10 mL of water is -5.3degrees. If the pathlength is 10 cm, what is the specific rotation of the compound?

The Beer’s Law as follows:

[α]_D = α/ℓ ×c

Here The observed rotation =-5.3 degrees

l = 10 cm

1 .0 cm = 0.1 dm

10 cm = 1 dm

amount = 1.2 g and volume = 10 ml

c = concentration in g/mL

= 0.12 g/ 10 ml

= 0.12 g/ ml

[α]_D = α/ℓ ×c

= -5.3 degrees /1 *0.12

= -1