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4 years ago

Element before carbon on the periodic table

Chemistry

2 answers:

Crazy boy [7]4 years ago

6 0

Answer:

Boron.

Explanation:

Boron is fifth in the periodic table, and carbon is sixth. It goes: hydrogen, helium, lithium, beryllium, boron, carbon...

Gemiola [76]4 years ago

5 0

Answer:Boron

Explanation:

it is element 5 represented by the letter B

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14. Explain, in terms of ions, why a 10.0-milliliter sample of 0.10 M NH4Cl(aq) is a poorer conductor of

Licemer1 [7]

Ionic compounds conduct electricity when dissolved in water, because the free-floating ions can carry charge. The more ions you have, the more readily the solution will carry that charge. 10.0 mL of 0.10 M NH4Cl has only 0.001 mol of NH4+ and 0.001 mol of Cl-, whereas 10.0 mL of 0.30 NH4Cl has 0.003 mol of NH4+ and 0.003 mol of Cl-. The 0.10 M sample is a poorer conducted of electricity because it has less ions in solution.

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3 years ago

What lab equipment do you use to measure the density of gold and how to use it

tigry1 [53]

Answer: Divide the mass of the object by its volume to yield the density of the object. For example, the object density = mass / (Vf – Vi). Compare the measured density to that of pure gold (19.3 g/cc) to determine whether the object is made of pure gold.

Explanation: I searched it

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3 years ago

Which of the following factors would reduce the yield of a reaction?

NikAS [45]

The products being more stable than the reactants is the factor which would reduce the yield of a reaction and is denoted as option B under standard conditions.

<h3>What is a Chemical reaction?</h3>

This is the process in which one or more substances which are referred to as reactants are converted into new substances which we call the products.

A chemical reaction involves atoms exhibiting different bond formation so as to ensure they acquire an octet configuration and promotes proper stability of the products.

When the products are more stable than the reactants it means it is unable to form other products thereby decreasing the yield which is why it was chosen as the most appropriate choice.

Read more about Chemical reaction here brainly.com/question/11231920

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2 years ago

Order the follow processes from (1) the least work done by the system to (5) the most work done by one mole of an ideal gas at 2

quester [9]

Answer : The order of process from (1) the least work done by the system to (5) the most work done by the system will be:

(1) < (5) < (3) < (4) < (2)

Explanation :

<u>The formula used for isothermally irreversible expansion is :</u>

$w=-p_{ext}dV\\\\w=-p_{ext}(V_2-V_1)$

where,

w = work done

$p_{ext}$ = external pressure

$V_1$ = initial volume of gas

$V_2$ = final volume of gas

<u>The expression used for work done in reversible isothermal expansion will be,</u>

$w=-nRT\ln (\frac{V_2}{V_1})$

where,

w = work done = ?

n = number of moles of gas = 1 mole

R = gas constant = 8.314 J/mole K

T = temperature of gas = $25^oC=273+25=298K$

$V_1$ = initial volume of gas

$V_2$ = final volume of gas

First we have to determine the work done for the following process.

(1) An isothermal expansion from 1 L to 10 L at an external pressure of 2.5 atm.

$w=-p_{ext}(V_2-V_1)$

$w=-(2.5atm)\times (10-1)L$

$w=-22.5L.atm=-22.5\times 101.3J=-2279.25J$

(2) A free isothermal expansion from 1 L to 100 L.

$w=-nRT\ln (\frac{V_2}{V_1})$

$w=-1mole\times 8.314J/moleK\times 298K\times \ln (\frac{100L}{1L})$

$w=-11409.6J$

(3) A reversible isothermal expansion from 0.5 L to 4 L.

$w=-nRT\ln (\frac{V_2}{V_1})$

$w=-1mole\times 8.314J/moleK\times 298K\times \ln (\frac{4L}{0.5L})$

$w=-5151.97J$

(4) A reversible isothermal expansion from 0.5 L to 40 L.

$w=-nRT\ln (\frac{V_2}{V_1})$

$w=-1mole\times 8.314J/moleK\times 298K\times \ln (\frac{40L}{0.5L})$

$w=-10856.8J$

(5) An isothermal expansion from 1 L to 100 L at an external pressure of 0.5 atm.

$w=-p_{ext}(V_2-V_1)$

$w=-(0.5atm)\times (100-1)L$

$w=-49.5L.atm=-49.5\times 101.3J=-5014.35J$

Thus, the order of process from (1) the least work done by the system to (5) the most work done by the system will be:

(1) < (5) < (3) < (4) < (2)

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3 years ago

Design a synthesis of acetophenone from benzene or toluene. 1275q Part 1 out of 5 Choose the best option for the nucleophile pre

Trava [24]

Answer:

A Fridiel craft catalyst will convert benzene to acetophenone.

Permanganate catalyst can be used to convert toluene to acetophenone.

Explanation:

Benzene can be reduced to acetophenone by the addition of anhydrous aluminium chloride, AlCl₃

The mechanism is as follows:

Benzene + Acetyl choloride → acetophenone

To convert toluene to acetophenone, the following steps are necessary:

Oxidation of Toluene to Benzoic acid.

This is done by refluxing toluene with alkaline potassium permanganate (KMnO₄+ Na₂CO₃).

Benzoic acid is converted to Benzoyl chloride by treating with thioyl chloride and heating at about 80 ⁰C.

Benzoyl chloride is treated with methyl lithium to form Acetophenone.

5 0

4 years ago