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3 years ago

Why was a condenser not necessary in the final distillation

1 answer:

6 0

Answer:Methyl benzoate has a very high boiling point i.e. 199°C.Therefore a water-cooled condenser is not advisable as it might crack the condenser tube.So in such cases air condenser tube is normally used for such distillation procedure.

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If this were a frictionless plane, what would be the ideal mechanical advantage?

slava [35]

<span>The answer is C)
mechanical advantage (MA = slope/height)
here length of slope = 9Hheight = H so mechanical advantage = ---- 9H/H= 9
</span>

8 0

3 years ago

an atmosphere is considered hazardous if it contains a hazardous gas in excess of 10 percent of the hazardous material's:

svlad2 [7]

Lower flammable limit means the lowest concentration of a material that will propagate a flame.

What is hazardous atmosphere?

It is an atmosphere that may expose employees to risk of death, incapacitation, impairment of ability to self-rescue, injury, or acute illness from one or more of following causes

Flammable gas, vapor, or mist in excess of 10 percent of lower flammable limit (LFL)
Airborne combustible dust at concentration that meets or exceeds its LFL

What is lower flammable limit?

It means the lowest concentration of a material that will propagate a flame.
The LFL is usually expressed as percent by volume of material in air (or other oxidant)
Atmospheres with concentration of flammable vapors at or above 10 percent of lower explosive limit (LEL) are considered hazardous when located in confined spaces.
However, atmospheres with flammable vapors below 10 percent of LEL are not necessarily safe. Such atmospheres are too lean to burn

Learn more about lower flammable limit at brainly.com/question/2456135

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6 0

10 months ago

A 46.9 gram sample of a substance has a volume of about 3.5 centimeters3. It is solid at a room temperature of 23ºC. Out of the

horrorfan [7]

Answer : (C) Hafnium is the most likely identity of the given substance.

Solution : Given,

Mass of given substance (m) = 46.9 g

Volume of given substance (V) = 3.5 $Cm^{3}$

First, find the Density of given substance.

Formula used :

$Density=\frac{\text{Mass of given substance}}{\text{Voume of given substance}}$

Now,put all the values in this formula, we get

$Density=\frac{46.9 g}{3.5 Cm^{3} }$ = 13.4 g/ $Cm^{3}$

So, we conclude that the density of given substance (13.4 g/ $Cm^{3}$ ) is approximately equal to the density of Mercury and Hafnium (13.53 and 13.31 g/ $Cm^{3}$ respectively).

According to the question the substance is solid at room temperature but Mercury is liquid at room temperature. So, Mercury is not identical to the given substance.

Another element i.e, Hafnium is the element whose density is approximately equal to the given substance and also solid at room temperature. And we know that the melting point of solid is high.

So, Hafnium is the most likely element which is the identity of the given substance.

3 0

2 years ago

Read 2 more answers

Consider the following weak acids and their Ka values: Acetic Acid Ka = 1.8×10^−5 Phosphoric Acid Ka = 7.5×10^−3 Hypochlorous Ac

vfiekz [6]

Answer:

a. Phosphoric Acid

b. Acetic Acid

c. Hypochlorous Acid

Explanation:

A buffer works when the pH of this one is in pKa ± 1. That means, to find which buffer system works in some pH you need to find pKa:

pKa = -log Ka

<em>pKa Acetic acid:</em>

-log1.8x10⁻⁵ = 4.74

<em>pKa phosphoric acid:</em>

-log7.5x10⁻³ = 2.12

<em>pKa hypochlorous acid:</em>

-log3.5x10⁻⁸ = 7.46

a. For a pH of 2.8 the best choice is phophoric acid because its effective range is: 1.12 - 3.12 and 2.8 is between these values.

b. pH 4.5. Acetic acid. effective between pH's 3.74 - 5.74

c. pH 7.5. Hypochlorous acid that works between 6.46 and 8.46

7 0

2 years ago

How many grams are in 3.14 moles of PI₃?

OverLord2011 [107]

Answer:

$\boxed {\boxed {\sf 1290 \ g \ PI_3}}$

Explanation:

We want to convert from moles to grams, so we must use the molar mass.

<h3>1. Molar Mass</h3>

The molar mass is the mass of 1 mole of a substance. It is the same as the atomic masses on the Periodic Table, but the units are grams per mole (g/mol) instead of atomic mass units (amu).

We are given the compound PI₃ or phosphorus triiodide. Look up the molar masses of the individual elements.

Phosphorus (P): 30.973762 g/mol
Iodine (I): 126.9045 g/mol

Note that there is a subscript of 3 after the I in the formula. This means there are 3 moles of iodine in 1 mole of the compound PI₃. We should multiply iodine's molar mass by 3, then add phosphorus's molar mass.