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3 years ago

List two detection (i.e. visualisation) techniques commonly used to visualise compounds in TLC.

Chemistry

1 answer:

olya-2409 [2.1K]3 years ago

7 0

Answer:

The most common non-destructive visualization method for TLC plates is ultraviolet (UV) light. A UV lamp can be used to shine either short-waved (254nm) or long-waved (365nm) ultraviolet light on a TLC plate with the touch of a button

Explanation:

hope this helps

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A researcher studying the nutritional value of a new candy places a 4.90 g sample of the candy inside a bomb calorimeter and com

snow_lady [41]

Answer:

449730.879 cal/g

Explanation:

Given data:

Mass of sample = 4.9 g

Change in temperature = 2.08 °C (275.23 k)

Heat capacity of calorimeter = 33.50 KJ . K⁻¹

Solution:

C(candy) = Q/m

Q = C (calorimeter) × ΔT

C(candy) = C (calorimeter) × ΔT / m

C(candy) = 33.50 KJ . K⁻¹ × 275.23 K / 4.90 g

C(candy) = 9220.205 KJ / 4.90 g

C(candy) = 1881.674 KJ / g

It is known that,

1 KJ /g = 239.006 cal/g

1881.674 × 239.006 = 449730.879 cal/g

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3 years ago

Hydrogen has three isotopes, 1H, 2H, and 3H. What is the difference between these three isotopes?

Firdavs [7]

C... The number of neutrons ranges from 1H with 0 neutron, 2H with 1 neutron and 3H with 2 neutrons.

6 0

3 years ago

Read 2 more answers

In a periodic table, dots around an elements symbol indicate the number of valence electrons in an atom ? True Or False

Liono4ka [1.6K]

True,I think.(so don't really count on my answer sorry :D)

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2 years ago

Describe the three values in a learner-centred curriculum that a teacher can use

ad-work [718]

Answer:

to talk in a way that the class can all understand . help them in thing they are falling . and have a good relashaship.

Explanation:

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2 years ago

A reaction vessel is charged with hydrogen iodide, which partially decomposes to molecular hydrogen and iodine: 2HI (g) H2(g) +

leonid [27]

Answer:

The value of the equilibrium constant: $K_{p} = 0.25$

Explanation:

Given reaction: 2HI (g) ⇌ H₂(g) + I₂(g)

Number of moles of- HI: n₁ = 2 mole; H₂: n₂ = 1 mole; I₂: n₃ = 1 mole

Total number of moles: n = n₁ + n₂ + n₃ = 2 + 1 + 1 = 4 moles

The equilibrium constant for the given reaction is given as:

$K_{p} = \frac{pH_{2}\; pI_{2}}{(pHI)^{2}}$

Given: Temperature: T = 425 °C = 425 + 273 = 698 K

The partial pressure: pHI = 0.708 atm,

and, pH₂ = pI₂

∵ partial pressure of a given gas: pₐ = Χₐ . P

Here, P is the total pressure

Χₐ is the mole fraction of given gas and is given by the equation

$\chi_{a} = \frac{number \, of \,moles \,of \,given \,gas (n_{a})}{total \,number \,of \,moles (n)}$

Mole fraction for HI: $\chi_{1} = \frac {n_{1}}{n} = \frac {2}{4} = 0.5$

Mole fraction for H₂: $\chi_{2} = \frac {n_{2}}{n} = \frac {1}{4} = 0.25$

Mole fraction for I₂: $\chi_{3} = \frac {n_{3}}{n} = \frac {1}{4} = 0.25$

Thus, Χ₂ = Χ₃ = 0.25

The partial pressure of HI is given by;

pHI = Χ₁ P

0.708 atm = 0.5 × P

⇒ P = 1.416 atm

As the partial pressures: pH₂ = pI₂

∴ pH₂ = pI₂ = Χ₂ P = Χ₃ P = 0.25 × 1.416 atm = 0.354 atm

Therefore, the value of Kp can be calculated as:

$K_{p} = \frac{pH_{2}\; pI_{2}}{(pHI)^{2}}$

$K_{p} = \frac{0.354 atm\times 0.354 atm}{(0.708 atm)^{2}} = 0.25$

Therefore, the value of the equilibrium constant:  $K_{p} = 0.25$

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3 years ago