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3 years ago

Is caffeine optically active

1 answer:

7 0

Caffeine is not optically active because it is a planar heterocycle. When you say optically active, it means that compounds have molecules which are chiral. Chirality is the property of molecules as a result of its structure. And when you say planar heterocycle, molecules are flat and the ring should contain atoms located in a similar plane.

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The H 2 produced in a chemical reaction is collected through water in a eudiometer. If the pressure in the eudiometer is 760.0 t

siniylev [52]

Answer:

the pressure (torr) of theH₂ gas is 736.2 torr

Explanation:

Given that

The H₂ gas produced in a chemical reaction is collected through water in a eudiometer; during this process, the gas collected contains some droplets of water vapor along with these gas.

So; the total pressure in the eudiometer = Pressure in the H₂ gas - Pressure of the water vapor

Where;

$P_{Totsl}$ = total pressure in the eudiometer = 760.0 torr

$P_{H_2}$ = Pressure in the H₂ gas = ???

$P_{H_2O}$ = Pressure in the water vapor = 23.8 torr

Now:

$P_{Totsl}$ = $P_{H_2}$ + $P_{H_2O}$

- $P_{H_2}$ = + $P_{H_2O}$ - $P_{Totsl}$

$P_{H_2}$ = - $P_{H_2O}$ + $P_{Totsl}$

$P_{H_2}$ = (- 23.8 + 760) torr

$P_{H_2}$ = 736.2 torr

Thus; the pressure (torr) of theH₂ gas is 736.2 torr

8 0

4 years ago

Materials expand when heated. Consider a metal rod of length L0 at temperature T0. If the temperature is changed by an amount ΔT

marysya [2.9K]

Answer:

(a) The length at temperature 180°C is 40.070 cm

(b) The length at temperature 90°C is 64.976 inches

Explanation:

(a) The given parameters are

The thermal expansion coefficient, α for steel = 1.24 × 10⁻⁵/°C

The initial length of the steel L₀ = 40 cm

The initial temperature, t₀ = 40°C

The length at temperature 180°C = L

Therefore, from the given relation, for change in length, ΔL, we have;

ΔL = α × L₀ × ΔT

The amount the temperature changed ΔT = 180°C - 40°C = 140°C

Therefore, the change in length, ΔL, is found as follows;

ΔL = α × L₀ × ΔT = 1.24 × 10⁻⁵/°C × 40 × 140°C = 0.07 cm

Therefore, L = L₀ + ΔL = 40 + 0.07 = 40.07 cm

The length at temperature 180°C = 40.07 cm

(b) Given that the length at T = 120°C is 65 in., we have;

The temperature at which the new length is sought = 90°C

The amount the temperature changed ΔT = 90°C - 120°C = -30°C

ΔL = α × L₀ × ΔT = 1.24 × 10⁻⁵/°C × 65 × -30°C = -0.024375 inches

The length, L at 90°C is therefore, L = L₀ + ΔL = 65 - 0.024375 = 64.976 in.

The length at temperature 90°C = 64.976 inches

Therefore;

L = 60 + α × 60 × (T - 150°C)

L = 60 + α × 60 × T - 9000 × α

L(T, α) = 60·α·T - 9000·α + 60

7 0

4 years ago

Solar power would be most successful as an energy source in

dangina [55]

Answer:

The correct answer is: a. Southern California and Australia.

Explanation:

The solar power, in order to be more efficient and more productive, needs to be produced in places that have a lot of sunny days throughout the year. So the wisest and most practical thing to do is to install solar panels at places that are warm and sunny for most of the year. The southern part of California and most of Australia would be excellent choices for something like this. Both places have predominantly warm weather throughout the year, and more important, they have a lot of sunny days throughout the year. That provides the perfect conditions for harvesting the solar energy and use it as an energy source.

3 0

3 years ago

Read 2 more answers

At a particular temperature, the solubility of Kr in water is 0.060 M when the partial pressure is 0.90 atm. What partial pressu

elena55 [62]

At a particular temperature, the solubility of He in water is 0.060 M when the partial pressure is 0.90 atm. 2.27 atm is the partial pressure of Kr would give a solubility of 0.150 M.

<h3>What is Henry's Law ?</h3>

According to Henry's law, the weight of a gas dissolved by a liquid is proportional to the pressure of the gas onto the liquid.
With very few exceptions, a solute molecule in an extremely diluted solution will only have solvent molecules as its close neighbors. This means that the likelihood that a specific solute molecule will escape into the gas phase is predicted to be independent of the total concentration of solute molecules.

Solution:

The solubility of gas is directly proportional to partial pressure. It is expressed as:

S = $K_ h \times P _g_a_s$

where, S = Solubility of gas

$K_h$ = Henry's Law constant

$P_g_a_s$ = Partial pressure of gas

Now, put the values in above expression we get

0.060M = $K_h$ × 0.9 atm

$K_h$ = = 0.066 M/atm

Now we have to find the partial pressure of He

0.150 M = 0.066 M/atm × $P_g_a_s$

$P_g_a_s$ = 2.27 atm

Learn more about the Henry's Law : brainly.com/question/23204201

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3 0

2 years ago

An aqueous of H3PO4 was prepared by dissolving 8.85 g in enough water to make 350.0 mL solution. Also, an aqueous solution of Ca

vivado [14]

Answer:

25.0 mL

Explanation:

1. Gather the information in one place.

MM: 98.00 74.09

2H3PO4 + 3Ca(OH)2 → Ca3(PO4)2 + 6H2O

m/g: 8.85 15.76

V/mL: 350.0 550

2. Moles of H3PO4

n = 8.85 g × (1 mol/98.00 g) = 0.09031 mol H3PO4

3. Moles of Ca(OH)2

n = 15.76 g × (1 mol/74.09 g) = 0.2126 mol Ca(OH)2

4. Moles of Ca(OH)2 in 25.0 mL Solution

n = 0.2126 mol × (25.0 mL/550 mL) = 0.009 663 mol Ca(OH)2

5. Moles of H3PO4 needed

From the balanced equation, the molar ratio is 2 mol H3PO4: 3 mol Ca(OH)2

n = 0.009 663 mol Ca(OH)2 × (2 mol H3PO4/3 mol Ca(OH)2)

= 0.006 442 mol H3PO4

6. Volume of H3PO4

V = 0.006 442 mol ×( 350.0 mL/0.09031 mol) = 25.0 mL H3PO4

It will take 25.0 mL of the H3PO4 solution to neutralize 25.0 mL of the Ca(OH)2 solution.

8 0

4 years ago