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nexus9112 [7]
3 years ago
7

Synthetic fibres catch fire easily so they are_____​

Chemistry
1 answer:
Margaret [11]3 years ago
8 0

Answer:

artificial polymer fibers that melt upon heating

Explanation:

You might be interested in
A solution of sodium chloride in water has a vapor pressure of 19.6 torr at 25°C. What is the mole fraction of NaCl in this solu
Debora [2.8K]

Answer:

Mole fraction of Nacl is 0.173

Explanation:

we know that

P_{sol}=\chi_{solvent}P^0_{solvent}

where,

P sol  - the vapor pressure of the solution

χ  solvent - the mole fraction of the solvent

P ∘ solvent  - the vapor pressure of the pure solvent

This means that in order to be able to calculate the mole fraction of sodium chloride, you need to know what the vapor pressure of pure water is at  

25 ° C  You can use an online calculator to find that the vapor pressure of pure water at  25 C  is equal to about  23.8 torr .

\chi_{water}= \frac{P{sol}}{P^0{water}}

\chi_{water}= \frac{19.6}{23.8}

=0.827

Also we know that

\chi_{water}+\chi_{Nacl}= 1

This means that the mole fraction of sodium chloride is

χ_{Nacl}= 1-Χ_{water}

= 1-0.827 =0.173

3 0
3 years ago
What is the mass of substance that exactly fills a 247.2 mL container? The density of the substance is 0.81 g/mL. Give the answe
matrenka [14]

Answer:

<h2>mass = 200.23 g</h2>

Explanation:

The density of a substance can be found by using the formula

Density =  \frac{mass}{volume}

Since we are finding the mass

<h3>mass = Density × volume</h3>

From the question

Density = 0.81 g/mL

volume = 247.2 mL

Substitute the values into the above formula and solve for the mass

mass = 0.81 × 247.2

= 200.232

We have the final answer as

<h3>mass = 200.23 g to 2 decimal places</h3>

Hope this helps you

3 0
3 years ago
determine the freezing point depression of a solution that contains 30.7 g glycerin (c3h8o3, molar mass
Blababa [14]

The freezing point depression of a solution containing 30.7 g of glycerin  is  calculated as -1.65°C

Equating :

It is given that,

Given mass of glycerin is = 30.7 grams (Solute)

Volume of water = 376 mL

K_{f}or molar -freezing-depression point is = 1.86°C/m

Molar mass of glycerin = 92.09 g/mole

Now, to work out the value, the mass of water should be known. Thus, to calculate, the formula used will be:

Mass = Density X Volume

Mass = 1.0 g/mL X 376 mL

Mass = 376 g or 0.376 Kg

Using the formula of melting point depression, the equation becomes:

             ΔT_{f} = i ×K_{f} ×m

T⁰-T_{s}  = i *K_{f} *\frac{mass of glycerin}{molar mass of glycerin * mass of water     in     kg}

in which,

ΔT_{f} = change in freezing point

ΔT_{s} = freezing point of solution that has to be find

ΔT° = freezing point of water ()

Since, glycerin is a non-electrolyte, the Van't Hoff factor will be 1.

Substituting the values in the above equation:

0⁰C₋T_{s} = 1 ×1.86°C/m ×\frac{30.7}{92.09g/mol * 0.376kg}

T_{s} = -1.65°C

Thus, the freezing point depression of a solution is  -1.65°C

<h2 />

Freezing point depression

Freezing point depression is a colligative property observed in solutions that results from the introduction of solute molecules to a solvent. The freezing points of solutions are all less than that of the pure solvent and is directly proportional to the molality of the solute

Is melting point elevation or depression?

Boiling point elevation is that the raising of a solvent's boiling point due to the addition of a solute. Similarly, melting point depression is the lowering of a solvent's freezing point due to the addition of a solute. In fact, because the boiling point of a solvent increases, its melting point decreases

Learn more about freezing point depression :

brainly.com/question/26525184

#SPJ4

8 0
1 year ago
Find the density of an 8 gram rock if the water in a graduated cylinder rises from 25.0 mL to
Olin [163]

To measure the density of the stone placed in a graduated cylinder let us follow these steps bellow

  1. Measure the volume of water poured into a graduated cylinder
  2. Place the object in the water and remeasure the volume.
  3. The difference between the two volume measurements is the volume of the object.
  4. Divide the mass by the volume to calculate the density of the object.

<em>We know that the formula for density is given as </em>

Given data

Mass = 8gram

Initial Volume of water in cylinder = 25mL

Final Volume of water in cylinder  = 29mL

Hence the volume of the rock  = 29-25 = 4mL

Therefore the density of the rock = 8/4 = 2 g/mL

Learn more:

brainly.com/question/17336041

6 0
2 years ago
List four observation that suggest a chemical change is occuring
andrezito [222]
1.) Gas given off
2.) precipitate formed
3.) large amount of heat given off
4.) Color change
8 0
3 years ago
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