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2 years ago

Which of the following are present both before and after a chemical reaction?

Chemistry

2 answers:

Harrizon [31]2 years ago

5 0

That would be a catalyst, it makes the reaction faster.

valina [46]2 years ago

4 0

Catalysts is wrong because it is never in the chemical equation. It only speeds up the reactions. A is wrong because reactants are only before the chemical reaction. D is wrong because products are only after the chemical reaction. It's C because the energy is still in the molecules and is not lost when it goes through the chemical reaction. Hope this helps! ;)

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Ketones undergo a reduction when treated with sodium borohydride, NaBH4. The product of the above reaction has the following spe

Anna71 [15]

Answer:

The product is cyclohexanol

Explanation:

Firstly,

A ketone undergo a borohydride reduction reaction to form an alcohol as below,

R-CO-R' ⇒ R-CO(OH)-R'

IR Spectrum confirms that alcohol group is existed with the peak at 3400 cm⁻¹
From 1H-NMR, the product has 10 hydrogen atoms, the MS suggest that the formula is C₅H₁₀O (M = 86). With this formula, the alcohol is monosaturated. Since, the substance already underwent reduction reaction, the only way to suggest a monosaturated compound is a cyclic alcohol. So the compound is cyclopentanol.
Check with other spectroscopic properties,

3 signals of 13C NMR confirms the structure is symmetrical, δ 24.2, (-CH₂-CH₂-CH(CH₂-)-OH), δ 35.5 (-CH₂-CH₂-CH(CH₂-)-OH), δ 73.3 (-CH₂-CH₂-CH(CH₂-)-OH).

1H NMR confirms,

1.56 δ (4H, triplet) - (-CH₂-CH₂-CH-OH) ; triplet as coupling with 2 H,

1.78 δ (4H, multiplet) - (-CH₂-CH₂-CH-OH); multiplet as coupling with 2H of CH₂, 1 H of CH

3.24 δ (1H, quintet); - (-CH₂-CH₂-CH(CH₂-)-OH), coupling with4 H of 2 group of CH₂

3.58 δ (1H, singlet); - (-CH₂-CH₂-CH(CH₂-)-OH), hydrogen of alcohol group, not tend to coupling with other hydrogen

4 0

3 years ago

What volume of 1.10 M SrCl2 is needed to prepare 525 mL of 5.00 mM SrCl2?

grigory [225]

Answer:- 2.39 mL are required.

Solution:- It's a dilution problem and to solve this type of problems we use the dilution equation:

$M_1V_1=M_2V_2$

Where, $M_1$ and $M_2$ are molarities of concentrated and diluted solutions and $V_1$ and $V_2$ are their respective volumes.

$M_1$ = 1.10M

$M_2$ = 5.00mM = 0.005M (since, mM stands for milli molar and M stands for molar. 1M = 1000mM)

$V_1$ = ?

$V_2$ = 525 mL

Let's plug in the given values in the formula:

$1.10M(V_1)=0.005M(525mL)$

$V_1=(\frac{0.005M*525mL}{1.10M})$

$V_1=2.39mL$

So, 2.39 mL of 1.10M are needed to make 525 mL of 5.00mM solution.

7 0

3 years ago

How are elements usually found

riadik2000 [5.3K]

The answer is A cause gas clouds hold elements in it

5 0

3 years ago

Read 2 more answers

Please help me I can describe a real-world situation in which opposite quantities combine to make zero.

ozzi

A hydrogen atom has 0 charge because its two constituents are oppositely charged; and understand p + q as the number located a distance |q| from p, in the positive or negative direction depending on whether q is positive or negative.

6 0

3 years ago

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Plants and animals use different energy storage molecules, yet they both use the same mechanism to "burn" their stored energy. H

jek_recluse [69]

Answer:

The breaking of the chemical bonds of a storage molecule transfer energy, no what molecule is stored.

Explanation:

Being successful of plants and animals does not necessary depend on the stored molecule but on the energy being transferred during their breaking.

8 0

3 years ago