1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Orlov [11]
3 years ago
12

Let’s say you have 3 UV active spots in the crude material and co-spot TLC plate. One has the same Rf value as the starting mate

rial and the other 2 are very different. What could these 2 nonstarting material spots be? Use structures and words. Hint: think about the nucleophilic addition of the hydride.

Chemistry
2 answers:
Troyanec [42]3 years ago
8 0

Answer:

Answer: (1R,2S) / (1S, 2R) , (1R,2R) / (1S, 2S)  

Explanation:

Sodium borohydride reduction of benzoin will give four possible stereo isomers out of which are (1R,2S) - (1S, 2R) isomers and (1R,2R) - (1S, 2S) isomers which are known as enantiomers.

In general enantiomers show single spot in the TLC as they do not show any difference in Rf value (i.e) (1R,2S) - (1S, 2R) isomers show only one spot although they are two compounds and also (1R,2R) - (1S, 2S) isomers also show one spot. That is the reason why you are observing two spots in the TLC ( of reaction mixture) other than starting materilal.

Sveta_85 [38]3 years ago
3 0

Answer:

Explanation:

find the solution below

You might be interested in
Is "average rainfall is 31.96 inches in miami" a climate or weather
n200080 [17]

Answer:

hvhvfhvfhbvfhvbbbbbbb

Explanation:

5 0
3 years ago
Read 2 more answers
A sample of ammonia gas was allowed to come to equilibrium at 400 K. 2NH3(g) <---> N2(g) 3H2(g) At equilibrium, it was fou
Softa [21]

Answer:

Kc for this equilibrium is 2.30*10⁻⁶

Explanation:

Equilibrium occurs when the rate of the forward reaction equals the rate of the reverse reaction and the concentrations of reactants and products are held constant.

Being:

aA + bB ⇔ cC + dD

the equilibrium constant Kc is defined as:

Kc=\frac{[C]^{c}*[D]^{d}  }{[A]^{a} *[B]^{b} }

In other words, the constant Kc is equal to the multiplication of the concentrations of the products raised to their stoichiometric coefficients by the multiplication of the concentrations of the reactants also raised to their stoichiometric coefficients. Kc is constant for a given temperature, that is to say that as the reaction temperature varies, its value varies.

In this case, being:

2 NH₃(g) ⇔ N₂(g) + 3 H₂(g)

the equilibrium constant Kc is:

Kc=\frac{[N_{2} ]*[H_{2} ]^{3}  }{[NH_{3} ]^{2} }

Being:

  • [N₂]= 0.0551 M
  • [H₂]= 0.0183 M
  • [NH₃]= 0.383 M

and replacing:

Kc=\frac{0.0551*0.0183^{3}  }{0.383^{2} }

you get:

Kc= 2.30*10⁻⁶

<u><em>Kc for this equilibrium is 2.30*10⁻⁶</em></u>

8 0
3 years ago
Please help me l don’t understand please !!!!!!
garik1379 [7]

Answer: C

Explanation:

he never had evidence in the first place that was nearly enough.

7 0
3 years ago
V1T2 = V2T1 is an expression of who’s law
Andru [333]

<u>Answer:</u>

It is the expression of Charles' Law.

<u>Explanation:</u>

The given expression V1T2 = V2T1 is the formula for the Charles' Law.

A special case of an ideal gas is named as the Charles' Law. This law applies to ideal gases only which are at constant pressure.

According to this law, the volume of a fixed mass of a gas is directly proportional to its temperature and is given by:

V1T2 = V2T1

6 0
3 years ago
Read 2 more answers
Any help would be appreciated. Confused.
masya89 [10]

Answer:

q(problem 1) = 25,050 joules;  q(problem 2) = 4.52 x 10⁶ joules

Explanation:

To understand these type problems one needs to go through a simple set of calculations relating to the 'HEATING CURVE OF WATER'. That is, consider the following problem ...

=> Calculate the total amount of heat needed to convert 10g ice at -10°C to steam at 110°C. Given are the following constants:

Heat of fusion (ΔHₓ) = 80 cal/gram

Heat of vaporization (ΔHv) = 540 cal/gram

specific heat of ice [c(i)] = 0.50 cal/gram·°C

specific heat of water [c(w)] = 1.00 cal/gram·°C

specific heat of steam [c(s)] = 0.48 cal/gram·°C

Now, the problem calculates the heat flow in each of five (5) phase transition regions based on the heating curve of water (see attached graph below this post) ...   Note two types of regions (1) regions of increasing slopes use q = mcΔT and (2) regions of zero slopes use q = m·ΔH.

q(warming ice) =  m·c(i)·ΔT = (10g)(0.50 cal/g°C)(10°C) = 50 cal

q(melting) = m·ΔHₓ = (10g)(80cal/g) 800 cal

q(warming water) = m·c(w)·ΔT = (10g)(1.00 cal/g°C)(100°C) = 1000 cal

q(evaporation of water) =  m·ΔHv = (10g)(540cal/g) = 5400 cal

q(heating steam) = m·c(s)·ΔT = (10g)(0.48 cal/g°C)(10°C) = 48 cal

Q(total) = ∑q = (50 + 800 + 1000 + 5400 + 48) = 7298 cals. => to convert to joules, multiply by 4.184 j/cal => q = 7298 cals x 4.184 j/cal = 30,534 joules = 30.5 Kj.

Now, for the problems in your post ... they represent fragments of the above problem. All you need to do is decide if the problem contains a temperature change (use q = m·c·ΔT) or does NOT contain a temperature change (use q = m·ΔH).    

Problem 1: Given Heat of Fusion of Water = 334 j/g, determine heat needed to melt 75g ice.

Since this is a phase transition (melting), NO temperature change occurs; use q = m·ΔHₓ = (75g)(334 j/g) = 25,050 joules.

Problem 2: Given Heat of Vaporization = 2260 j/g; determine the amount of heat needed to boil to vapor 2 Liters water ( = 2000 grams water ).

Since this is a phase transition (boiling = evaporation), NO temperature change occurs; use q = m·ΔHf = (2000g)(2260 j/g) = 4,520,000 joules = 4.52 x 10⁶ joules.

Problems containing a temperature change:

NOTE: A specific temperature change will be evident in the context of problems containing temperature change => use q = m·c·ΔT. Such is associated with the increasing slope regions of the heating curve.  Good luck on your efforts. Doc :-)

5 0
3 years ago
Other questions:
  • After a hormone enters the bloodstream, it is transported throughout the body, but the hormone only affects certain cells. The r
    6·1 answer
  • Calcium oxide (CaO) reacts with tetraphosphorus decoxide (P4O10) to form calcium phosphate (Ca3(P4O10)2) according to this equat
    10·1 answer
  • What is the compound of scI2
    11·1 answer
  • How many grams of sulfur are in 164 g of potassium sulfate?
    10·1 answer
  • Discuss the phenomena of sunrise and sunset seen on Earth and describe how they will be different from the perspective of outer
    15·1 answer
  • 3. Which of the rocks from the table would be classified as metamorphic rocks?
    5·1 answer
  • Which reaction will occur? 2NaBr I2 Right arrow. 2NaI Br2 2Fe Al2O3 Right arrow. 2Al Fe2O3 2AgNO3 Ni Right arrow. Ni(NO3)2 2Ag P
    13·1 answer
  • Help me please (~ ̄- ̄)~​
    14·2 answers
  • 1. What is the pH of a solution with a [H3O+] concentration of 4.32 x 10-2 M?
    6·1 answer
  • (a) Which region of Earth’s crust is not involved in the phosphorus cycle?
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!