49. Which type of precursor is used
as reactant in intramolecular Claisen
condensation?
O One molecule with an ester end
O Two molecules of ester
O One molecule with two ester ends
O One molecule of ester and enolate​

Answer:

For a dot structure, I will explain it.

Explanation:

So there's an S (the symbol for Sulfur) and on the top, there are two dots, as well as two on the left side. On the bottom and right of the symbol, there is only 1 dot on each of these sides.

The correct Lewis structure for the sulfur atom has six dots. These six dots are distributed in such a way that two dots are present at the top, two are on the left side, and one each is on the bottom and right side.

Lewis's structure may be defined as a structural representation of a molecule where dots are used to show electron positions around the atoms and lines or dot pairs represent covalent bonds between atoms.

Sulfur has an atomic number of 16. Its electronic configuration is 2, 8, and 6. It represents that the sulfur atom has six valence electrons. These six electrons are represented by dots in the Lewis structure.

Each sulfur atom is connected to an identical atom on either side by single covalent bonds. This ensures the sulfur completes its octet.

Therefore, the correct Lewis structure for the sulfur atom has six dots.

To learn more about Lewis's structure, refer to the link:

https://brainly.com/question/6224949

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Answer:

Chemical digestion is a vital part of the digestive process. Without it, your body wouldn't be able to absorb nutrients from the foods you eat, also chemical digestion uses enzymes to break down food

mechanical digestion involves physical movements, such as chewing and muscle contractions,

Explanation:

Answer:

C

Explanation:

Answer:

Hey mate....

Explanation:

This is ur answer...

Plastics are produced from natural gas, feedstocks derived from natural gas processing, and feedstocks derived from crude oil refining.

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Answer:

sliding friction occurs

Answer:

Sliding friction is occurs

Answer:

Chemical bonds

Explanation:

the chemicals in your food are what give you energy when they break down, that's how it releases energy Into your body.

Answer:

The strength of an electric field as created by source charge Q is inversely related to square of the distance from the source. This is known as an inverse square law. Electric field strength is location dependent, and its magnitude decreases as the distance from a location to the source increases

Answer:

Increase

Explanation:

More collisions mean more force, so the pressure will increase. When the volume decreases, the pressure increases. This shows that the pressure of a gas is inversely proportional to its volume.

Answer:

a) 0.70

b) 7.00

c) 0.85

d) 12.15

e) 1.30

Explanation:

The neutralization reaction involved in the titration is:

HClO₄(aq) + KOH(aq) → KClO₄(aq) + H₂O(l)

According to the chemical equation, 1 mol of HClO₄ reacts with 1 mol of KOH (1 equivalent of acid with 1 equivalent of base). The moles are calculated from the product of the molar concentration (M) and the volume in liters.

We have the following moles of acid (HClO₄):

40.0 mL x 1 L/1000 mL = 0.04 L

0.200 mol/L x 0.04 L = 8 x 10⁻³ moles HClO₄

Since HClO₄ is a strong acid (completely dissociated into H⁺ and ClO₄⁻ ions), the moles of HClO₄ are equal to the moles of H⁺. Then, we can calculate the initial pH:

[H⁺] = 0.200 M → pH = -log [H⁺] = -log (0.200) = 0.70

Now, we calculate the pH after the addition of KOH. Since KOH is a strong base, the concentration of KOH is equal to the concentration of OH⁻ ions.

a) 0.0 mL

No KOH is added, so the pH is the initial pH: 0.70

b) 80.0 mL KOH

80.0 mL x 1 L/1000 mL = 0.08 L

0.100 mol/L x 0.08 L = 8 x 10⁻³ moles KOH = 8 x 10⁻³ moles OH⁻

After neutralization we have:

8 x 10⁻³ moles H⁺ - 8 x 10⁻³ moles OH⁻ = 0

The neutralization reaction is complete and there is no remaining H⁺ from the acid. The concentration of H⁺ is equal to the concentration of H⁺ of water:

[H⁺] = 1 x 10⁻⁷ M → pH = -log [H⁺] = -log (1 x 10⁻⁷) = 7.0

c) 10.0 mL KOH

10.0 mL x 1 L/1000 mL = 0.01 L

0.100 mol/L x 0.01 L = 1 x 10⁻³ moles KOH = 1 x 10⁻³ moles OH⁻

After neutralization we have:

8 x 10⁻³ moles H⁺ - 1 x 10⁻³ moles OH⁻ = 7 x 10⁻³ moles H⁺

The total volume is: V = 40.0 mL + 10.0 mL = 50 mL = 0.05 L

[H⁺] = 7 x 10⁻³ moles/0.05 L = 0.14  → pH = -log [H⁺] = -log (0.14) = 0.85

d) 100.0 mL KOH

100.0 mL x 1 L/1000 mL = 0.1 L

0.100 mol/L x 0.1 L = 0.01 moles KOH = 1 x 10⁻² moles OH⁻

After neutralization we have:

1 x 10⁻² moles OH⁻ - 8 x 10⁻³ moles H⁺ = 2 x 10⁻³ moles OH⁻

The total volume is: V = 40.0 mL + 100.0 mL = 140 mL = 0.14 L

[OH⁻] = 2 x 10⁻³ moles/0.14 L = 0.014  → pOH = -log [OH⁻] = -log (0.014) = 1.84

pH + pOH = 14 → pH = 14 - pOH = 14 - 1.84 = 12.15

e) 40.0 mL KOH

40.0 mL x 1 L/1000 mL = 0.04 L

0.100 mol/L x 0.04 L = 4 x 10⁻³ moles KOH = 4 x 10⁻³ moles OH⁻

After neutralization we have:

8 x 10⁻³ moles H⁺ - 4 x 10⁻³ moles OH⁻ = 4 x 10⁻³ moles H⁺

The total volume is: V = 40.0 mL + 40.0 mL = 80.0 mL = 0.08 L

[OH⁻] = 4 x 10⁻³ moles/0.08 L = 0.05 M  → pH = -log [H⁺] = -log (0.05) = 1.30

Answer:

B

Explanation:

Answer:

B its correct because i did the test.

Explanation:

Answer:

B. To change from a liquid state to a solid state is called Freezing

Answer:

Your Answer Is

B. Freezing

Explanation:

Hope It Help

Answer:

1 2 2

Explanation:

Answer:

they hace a rock surface composition

Answer: Sodium salt

Explanation: sorry if this is wrong

Answer:

attached below

Explanation:

write the chemical equations for the test  and confirmation test

i.e.

i)Chemical equation for main copper test

ii)Chemical equation for copper confirmation test

iii)Chemical equation for main bismuth test

iv) Chemical equation for bismuth confirmation test

attached below are the chemical equations for the test and confirmation test

Answer:

Chromosphere

Explanation:

You see the middle layer of the sun’s atmosphere, the Chromosphere, at the start and end of a total eclipse.

Answer:

2. B. 5:3

3. C. mass and atoms only.

Explanation:

Hello there!

2. In this case, according to the given balanced chemical reaction it is possible to realize that the mole ratio of oxygen to carbon dioxide is B. 5:3 since there is a 5 on O2 and a 3 on CO2.

3. In this case, according to the law of conservation of mass it is possible to realize that matter cannot be created nor destroyed; for that reason both mass and atoms must remain unchanged as the reaction takes place; therefore the answer is C. mass and atoms only.

Best regards!

Answer:

It should be B

Explanation:

I hope this helps

Answer: The value of the equilibrium constant Kc for this reaction is 3.72

Explanation:

Equilibrium concentration of [tex]HNO_3[/tex] = [tex]\frac{15.5g}{63g/mol\times 9.5L}=0.026M[/tex]

Equilibrium concentration of [tex]NO[/tex] = [tex]\frac{16.6g}{30g/mol\times 9.5L}=0.058M[/tex]

Equilibrium concentration of [tex]NO_2[/tex] = [tex]\frac{22.5g}{46g/mol\times 9.5L}=0.051M[/tex]

Equilibrium concentration of [tex]H_2O[/tex] = [tex]\frac{189.0g}{18g/mol\times 9.5L}=1.10M[/tex]

Equilibrium constant is defined as the ratio of concentration of products to the concentration of reactants each raised to the power their stoichiometric ratios. It is expressed as [tex]K_c[/tex]  

For the given chemical reaction:

[tex]2HNO_3(aq)+NO(g)\rightarrow 3NO_2(g)+H_2O(l)[/tex]

The expression for [tex]K_c[/tex] is written as:

[tex]K_c=\frac{[NO_2]^3\times [H_2O]^1}{[HNO_3]^2\times [NO]^1}[/tex]

[tex]K_c=\frac{(0.051)^3\times (1.10)^1}{(0.026)^2\times (0.058)^1}[/tex]

[tex]K_c=3.72[/tex]

Thus  the value of the equilibrium constant Kc for this reaction is 3.72

Answer:

30.8 g of CO2.

Explanation:

Using malar masses of gasoline and carbon dioxide:

2 * (12*8 + 1*18) g gas yields 16(12 + 2*16) g of CO2

228...........................................  704 g CO2

1g   ................................................     704/228

10g ....................................................   (704*10)/228 = 30.8 g.

Answer:

Approximately [tex]3.06 \times 10^{2}\; \rm g[/tex] (approximately [tex]306\; \rm g[/tex].)

Explanation:

Calculate the quantity [tex]n[/tex] of lithium phosphate in [tex]V = 2.5\; \rm L[/tex] of this[tex]c = 1.06\; \rm M = 1.06\; \rm mol \cdot L^{-1}[/tex] lithium phosphate solution.

[tex]\begin{aligned}n &= c \cdot V\\ &= 2.5\; \rm L \times 1.06\; mol \cdot L^{-1}\\ &= 2.65\; \rm mol\end{aligned}[/tex].

Empirical formula of lithium phosphate: [tex]\rm Li_3PO_4[/tex].

Look up the relative atomic mass of [tex]\rm Li[/tex], [tex]\rm P[/tex],and [tex]\rm O[/tex] on a modern periodic table:

Calculate the formula mass of [tex]\rm Li_3PO_4[/tex]:

[tex]M(\rm Li_3PO_4) = 3 \times 6.94 + 30.974 + 4 \times 15.999 = 115.79\; \rm g \cdot mol^{-1}[/tex].

Calculate the mass of that [tex]n = 2.65\; \rm mol[/tex] of [tex]\rm Li_3PO_4[/tex] formula units:

[tex]\begin{aligned}m &= n \cdot M \\ &= 2.65\; \rm mol \times 115.79\; \rm g\cdot mol^{-1} \\ &\approx 3.06 \times 10^{2}\; \rm g \end{aligned}[/tex].

Answer:

the answer is gas

Explanation:

It is usually said that the sun is a fiery ball of gases, but, actually, most of it is plasma, which isn't quite the same thing, although hot gas and plasma are often used interchangeably. Plasma is known as the fourth state of matter, following solid, which is the first and coldest state.

Answer:

The correct answer is - the uterus.

Explanation:

The uterus or the womb is an organ that appears to be pear-shaped and it is hollow from inside where the fetus is developed and it is also called the birth canal. The uterus has two parts one is the cervix and the other is the corpus.

The cervix makes the lower part of the uterus and opens up into the vagina the external reproductive organ of the females. The corpus is the part that makes the main body of the uterus. The uterus is present between the bladder and rectum where the egg fertilized and implanted itself.

Answer: d)endothermic with a positive entropy change

Explanation:

Endothermic reactions are those in which heat is absorbed by the system and exothermic reactions are those in which heat is released by the system.

 Entropy is the measure of randomness or disorder of a system. If a system moves from  an ordered arrangement to a disordered arrangement, the entropy is said to decrease and vice versa.

As temperature of water decreases on dissolution of [tex]NH_4NO_3[/tex] , it means heat has been absorbed by [tex]NH_4NO_3[/tex] during dissolution and that heat is taken from water. Thus process is endothermic. As dissolution will lead in the formation of ions [tex]NH_4^+[/tex] and [tex]NO_3^-[/tex] , randomness will increase and thus there is a positive entropy change.

Answer: no answer

Explanation:

no anwser