Determine the mass, in grams, of 0.350 moles of s (1 mol of s has a mass of 32.07 g).

What is the melting point of a solution in which 3.5 grams of sodium chloride is added to 230 mL of water?

kirza4 [7]

We are going to use this equation:

ΔT = - i m Kf

when m is the molality of a solution

i = 2

and ΔT is the change in melting point = T2- 0 °C

and Kf is cryoscopic constant = 1.86C/m

now we need to calculate the molality so we have to get the moles of NaCl first:

moles of NaCl = mass / molar mass

= 3.5 g / 58.44

= 0.0599 moles

when the density of water = 1 g / mL and the volume =230 L

∴ the mass of water = 1 g * 230 mL = 230 g = 0.23Kg

now we can get the molality = moles NaCl / Kg water

=0.0599moles/0.23Kg

= 0.26 m

∴T2-0 = - 2 * 0.26 *1.86

∴T2 = -0.967 °C

8 0

3 years ago

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Four different objects are placed on a number line at 0. The chart describes the motion of each object. Using the information in

mote1985 [20]

The chart with the information to answer this question may be found in other Brainly's link, so I attach it now.

Answer:

Z

Explanation:

To facilitate the accompaniment of the reasoning, I copy the data here:

Object Motion

X 3 units left, 3 units right

Y 6 units right, 18 units right

W 8 units left, 24 units right

Z 16 units right, 8 units left

The distance is the scalar magnitude that indicates the total length of the path traveled.

The displacement is the vector that indicates how far the end point and the initial point are.

In order to calculate the distance, the displacement and the ratio r = distance/displacement, to check which object has a distance that is three times as great as its displacement, i.e. r = 3, we use this new chart:

Object Motion Distance Displacement ratio

X 3 units left, 3 units right 3 + 3 = 6 3 - 3 = 0 ∞

Y 6 units right, 18 units right 6 + 18 = 24 6 + 18 = 24 1

W 8 units left, 24 units right 8 + 24 = 32 -8 + 24 = 16 2

Z 16 units right, 8 units left 16 + 8 = 24 16 - 8 = 8 3

The ratios were calculated dividing the distance by the displacement: distance / displacement.

For the object Z, that was 24 / 8 = 3. Thus, the object that has a distance that is three times as great as its displacement is the object Z.

8 0

3 years ago

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Which term refers to compounds that can form hydrates but do not contain water molecules?

Lerok [7]

The term that refers to compounds that can form hydrates but do not contain water molecules is anhydrous.

6 0

3 years ago

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What is the lower concentration limit (vol%) at which a mixture of ethanol in air can explode?

liubo4ka [24]

Answer:

Lower explosive limit (LEL) of ethanol = 3.3%

Explanation:

In the case of alcohol, ethanol presents certain fire hazards. Its momentary flash point is 55ºF (12.9ºC), while the momentary flash point of gasoline is -45ºF (-42.8ºC), and the E85 mixture ranges between -20ºF and -4ºF (between -28 , 9ºC and -20ºC), and has a wider range of flammability limits than gasoline. For emergency response teams, this implies that during a release of the typical ethanol / gasoline mixture, the fuel can be expected to behave like gasoline: It is heavier than air - as we mentioned earlier - and can produce vapors and form flammable mixtures in the air, under most environmental conditions.

General properties and comparison with other inflambles products:

Flash point momentary Gasoline = -45 ° F

Ethanol = 55 ° F

E 85 = between -20º and -4º F

Flammability limits

Lower explosive limit (LEL) of ethanol = 3.3%

Upper Explosive Limit (UEL) = 19%

Lower explosive limit (LEL) of the mixture E 85 = 1.4%

Upper Explosive Limit (UEL) 85 = 19%

Lower explosive limit (LEL) of gasoline = 1.4%

Upper Explosive Limit (UEL) = 7.6%

They have a wider range than gasoline

4 0

2 years ago

Why do you turn a C-terminal aminoacid's carboxyl group into an ester before reducing it to an alcohol? Why not just use LiAlH4

Troyanec [42]

Answer:

Esters are both inorganic and organic acids .... Regarding the second question, it is believed that it is carried out in this way in order to recognize the C-terminal amino acid in a peptide within a protein

Explanation:

The explanation of this question is according to what was interpreted in the question, since it is considered that it is poorly written ...

What happens in this chemical reaction is that it first becomes an ester (organic or inorganic acid) so that it is later recognized in the complex peptide structure.

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3 years ago

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