why might the melting point of the crystals obtained in this experiment be close to but below one of the reference melting points and melt slowly over several degrees

Answers

Answer 1

Answer: hello the experiment related to your question is missing but I will provide a more general answer within the scope of your  question

answer :

presence of Impurities

Explanation:

The melting point of the crystals as obtained in the experiment will be close to but below reference melting points and will also melt slower because of the presence of impurities in the compound

Impurities alter the melting and freezing points from ideal freezing and melting points of compounds


Related Questions

g Calculate the percent yield when you start with 0.50 grams of salicylic acidand end with 0.33 grams of aspirin. The molecular weight of salicylic acid is 138.12 g/mol, and the molecular weight of aspirin is 180.157 g/mol.

Answers

Explanation:

hope the picture above helps you to understand:)

A beaker is filled to the 500 mL mark with alcohol. What increase in volume (in mL) does the beaker contain when the temperature changes from 5° C to 30° C? (Neglect the expansion of the beaker, evaporation of alcohol and absorption of water vapor by alcohol.) The volume coefficient of expansion γγ for alcohol = 1.12 x 10-4 K-1

Answers

Answer:

"1.4 mL" is the appropriate solution.

Explanation:

According to the question,

[tex]v_0=500[/tex][tex]\alpha =1.12\times 10^{-4}[/tex][tex]\Delta \epsilon = 25[/tex]

Now,

Increase in volume will be:

⇒ [tex]\Delta V = \alpha\times v_0\times \Delta \epsilon[/tex]

By putting the given values, we get

           [tex]=1.12\times 10^{-4}\times 500\times 25[/tex]

           [tex]=1.12\times 10^{-4}\times 12500[/tex]

           [tex]=1.4 \ mL[/tex]

Why ethanol is used in pectin extraction

Answers

Explanation:

is responsible for interrupting the interaction between pectins and solvent molecules

Part A: Calculate the mass of butane needed to produce 75.6g of carbon dioxide.

Part B: Calculate the mass of water produced when 5.48g of butane reacts with excess oxygen.

Answers

Answer:

Multiply the number of moles of butane by its molar mass, 58.12g/mol, to produce the mass of butane. Mass of butane = 18.8g.

Explanation:

Part B:

The mass of water produced when 4.86 g of butane(C4H10) react with excess oxygen is calculated as below

calculate the moles of C4H10 used = mass/molar mass

moles = 4.86g/58 g/mol =0.0838 moles

write a balanced equation for reaction

2 C4H10 + 13 O2 = 8 CO2 + 10 H2O

by use of mole ratio between C4H10 to H2O which is 2:10 the moles of

H20= 0.0838 x10/2 = 0.419 moles of H2O

mass = moles x molar mass

=0.419 molx 18 g/mol = 7.542 grams of water is formed

Determine the kinds of intermolecular forces that are present in each element or compound. Part A KrKr Check all that apply. Check all that apply. dispersion forces dipole-dipole forces hydrogen bonding

Answers

Answer:

The kinds of intermolecular forces that are present in each element Kr-Kr.

Explanation:

Since Kr is an inert gas and in atomic form only it is highly stable.

So, Kr gas does not form molecules.

Between the atoms of inert gas, there exist London dispersion forces.

Hence, the intermolecular forces that are present between Kr-Kr atoms is London dispersion forces.

100.0 mL of a 0.780 M solution of KBr is diluted to 500.0 mL. What is the new concentration of the solution?

Answers

5 times dilution
0.780M x 1/5 = 0.156M
Hope this help.

How many molecules of C 2H 5Br will be present if you had 4.52 g of this compound?

Answers

okay ty what what happened to me lol lolhope this helps i lol lol oh yeah that’s okay lol lol yeah lol lol !!! hope it helps :)

All --- is a good conductor of heat​

Answers

all metals is a good conductor of heat

Which probing question lies within the scope of physics?
O A.
Are fish in the open ocean
attracted by underwater sounds?
O B.
Does increasing the saltiness of
ocean water affect the speed
of sound in the water?
O C.
What effect does the release of industrial wastewater have on
the acidity of oceans?
D. What is the effect of rising sea temperatures on
ocean currents?

Answers

Answer:

answer number C is the correct answer for this

Draw a sketch showing what osmotic pressure is. Label on the sketch solute, solvent, hypertonic, hypotonic and semi permeable membrane.

Answers

Can you provide pictures please ??

What does Gibbs free energy predict?
A. It predicts what the rate of the reaction will be.
B. It predicts how high the activation energy is.
C. It predicts if entropy will increase or decrease.
D. It predicts whether or not a reaction will be spontaneous.

Answers

Answer:

It predicts whether or not a reaction will be spontaneous.

Explanation:

The equation;

∆G= ∆H - T∆S enables us to obtain the Gibbs free energy of a chemical process.

The Gibbs free energy value tells us whether a chemical process will be spontaneous or not.

When;

∆G>0 the reaction is not spontaneous

∆G=0 the reaction is at equilibrium

∆G<0 the reaction is spontaneous

Evaporation is commonly used to concentrate dissolved solids in a liquid feed stream and produce pure water vapor.

a. True
b. False

Answers

Answer:

True

Explanation:

Evaporation is the process by which a substance changes its state from liquid to gas. evaporation occurs at all temperatures but it's rate increases as temperature increases.

Pure water vapour can be produced by evaporation.

As the liquids are removed, the solids present in solution becomes more concentrated.

Match the following terms to their correct definitions.
ResetHelp
A cell that requires energy to bring about a nonspontaneous redox reaction.
An ion-containing conducting medium used to physically and chemically connect the two half-cells in an electrochemical cell.
A cell that requires energy to bring about a nonspontaneous redox reaction.
To move to drop area press Tab key.
faraday
salt bridge
anode
cathode
voltaic cell
electrolytic cell

Answers

Answer:

Electrolytic cell. Salt bridge.

Explanation:

Match the following terms to their correct definitions.

A cell that requires energy to bring about a nonspontaneous redox reaction. Electrolytic cell. In an electrolytic cell, energy is provided from an outer source, such as a battery. An ion-containing conducting medium used to physically and chemically connect the two half-cells in an electrochemical cell. Salt bridge. The salt bridge contains a salt (strong electrolyte) and it is fundamental in a voltaic cell.

Suppose you need to prepare 138.1 mL of a 0.190 M aqueous solution of NaCl. What mass, in grams, of NaCl do you need to use to make the solution

Answers

Answer:

Explanation:

·  44 g NaCl Explanation: The problem provides you with the molarity and volume of the target

The answer is rounded to two sig figs, the number of sig figs you have for the molarity of the solution.

The mass of a solute needed to prepare a solution with given volume is find by molarity. The mass of NaCl need to make a 138.1 mL solution of 0.190 M is 1.53 grams.

What is molarity ?

Molarity of a solution is a term to express its concentration. Mathematically, it is the ratio of no.of moles of solute to the volume of solution in litres.

Given that, the volume of solution is 138.1 mL. One litre solution is 1000 mL. Hence, 138.1 mL is 0.1381 L. The molarity of the solution is 0.190 M. From these data we can calculate the no.of moles of NaCl as below:

no.of moles = molarity × volume of solution in L

                    =  0.190 M × 0.1381 L

                    = 0.0262 moles.

This is the no.of moles required to make the solution.

Molecular mass of NaCl = 58.4 g/mol.

Thus mass of 0.0262 moles of NaCl = 0.0262  mol × 58.4 g/mol

                                                             = 1.53 g.

Therefore, the mass of NaCl required is 1.53 g.

To learn more about molarity, refer the link below:

https://brainly.com/question/16727614

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A compound that contains only carbon, hydrogen, and oxygen is 58.8% C and 9.87% H by mass. What is the empirical formula of this substance

Answers

Answer: The empirical formula of the compound becomes [tex]C_5H_{10}O_2[/tex]

Explanation:

The empirical formula is the chemical formula of the simplest ratio of the number of atoms of each element present in a compound.

Let the mass of the compound be 100 g

Given values:

% of C = 58.8%

% of H = 9.87%

% of O = [100 - 58.8 - 9.87] = 31.33%

Mass of C = 58.8 g

Mass of H = 9.87 g

Mass of O = 31.33 g

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)

To formulate the empirical formula, we need to follow some steps:

Step 1: Converting the given masses into moles.

Molar mass of C = 12 g/mol

Molar mass of H = 1 g/mol

Molar mass of O = 16 g/mol

Putting values in equation 1, we get:

[tex]\text{Moles of C}=\frac{58.8g}{12g/mol}=4.9 mol[/tex]

[tex]\text{Moles of H}=\frac{9.87g}{1g/mol}=9.87 mol[/tex]

[tex]\text{Moles of O}=\frac{31.33g}{16g/mol}=1.96mol[/tex]

Step 2: Calculating the mole ratio of the given elements.

Calculating the mole fraction of each element by dividing the calculated moles by the least calculated number of moles that is 1.96 moles

[tex]\text{Mole fraction of C}=\frac{4.9}{1.96}=2.5[/tex]

[tex]\text{Mole fraction of H}=\frac{9.87}{1.96}=5.03\approx 5[/tex]

[tex]\text{Mole fraction of O}=\frac{1.96}{1.96}=1[/tex]

Converting the mole fraction into whole numbers by multiplying them with 2.

[tex]\text{Mole fraction of C}=2.5\times 2=5[/tex]

[tex]\text{Mole fraction of H}=5\times 2=10[/tex]

[tex]\text{Mole fraction of O}=1\times 2=2[/tex]

Step 3: Taking the mole ratio as their subscripts.

The ratio of C : H : O = 5 : 10 : 2

Hence, the empirical formula of the compound becomes [tex]C_5H_{10}O_2[/tex]

The empirical formula of the substance is[tex]C_5H_{10}O_2[/tex].

Explanation:

Given:

A compound made up of 58.8% of carbon, 9.87% hydrogen, and oxygen.

To find:

The empirical formula of this substance.

Solution

The percentage of carbon in a given substance by mass = 58.8%

The percentage of hydrogen in a given substance by mass = 9.87%

The percentage of oxygen in a given substance by mass :

[tex]= 100\%-58.8\%- 9.87\%=31.33\%[/tex]

Consider 100 grams of a substance.

In 100 grams of substance:

The mass of carbon =58.8% of 100 g = 58.8 g

The mass of hydrogen = 9.87% of 100 g = 9.87 g

The mass of oxygen = 31.33% of 100 g= 31.33 g

The moles of carbon [tex]=\frac{58.8 g}{12.0107 g/mol}=4.90 mol[/tex]

The moles of hydrogen[tex]=\frac{9.87g}{1.00784g/mol}=9.79 mol[/tex]

The moles of oxygen[tex]=\frac{31.33g}{15.999g/mol}=1.96 mol[/tex]

let the empirical formula of the substance = [tex]C_xH_yO_z[/tex]

The value of subscript x:

[tex]=\frac{4.90 mol}{1.96 mol}=2.5[/tex]

The value of subscript y:

[tex]=\frac{9.79mol}{1.96 mol}=5[/tex]

The value of subscript z:

[tex]=\frac{1.96mol}{1.96 mol}=1[/tex]

The empirical formula of a substance :

[tex]C_{2.5}H_5O_1=C_{\frac{25}{10}}H_5O_1=C_{25}H_{50}O_{10}[/tex]

Reducing to the lowest whole numbers:

[tex]C_{25}H_{50}O_{10}=C_5H_{10}O_2[/tex]

The empirical formula of the substance is [tex]C_5H_{10}O_2[/tex].

Learn more about the empirical formula here:

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list four energy resources​

Answers

Answer:

Nuclear

Solar

Wind

Hydro

Geo-Thermal

Explanation:

Solar energy from the sun.Geothermal energy from heat inside the earth.Wind energyBiomass from plants.

hope it helps

stay safe healthy and happy....

g in the following three compounds(1,2,3) arrange their relative reactivity towards the reagent CH3Cl / AlCl3. Justify your order

Answers

Answer:

3 > 2> 1

Explanation:

Aromatic compounds undergo electrophilic substitution reaction with several electrophiles.

Some substituted benzenes are more reactive towards electrophilic aromatic substitution than unsubstituted benzene.

Certain groups of substituents increase the ease with which an aromatic compound undergoes aromatic substitution.

If we look at the compounds closely, we will notice that only toluene leads to easy reaction with CH3Cl / AlCl3. Thus is due to the +I inductive effect of -CH3 which stabilizes the negatively charged intermediate produced in the reaction.

True/False: Chemical reactions can NOT proceed in the reverse direction

Answers

The answer is most likely TRUE

When 2.50 moles of oxygen reacts with excess hydrogen gas how many grams of water is
produced?
2 H2 + O2--> 2 H20

Answers

Answer:

90grams

Explanation:

The reaction given in this question is as follows:

2H2 + O2 → 2H20

Based on this equation, 1 mole of oxygen gas (O2) produces 2 moles of water (H2O)

Hence, 2.50moles of oxygen gas will react with excess hydrogen gas to produce (2.5 × 2) = 5.0moles of water.

Using mole = mass/molar mass

Molar mass of water (H2O) = 1(2) + 16

= 18g/mol

5 = mass/18

mass = 18 × 5

mass of H2O = 90grams

Draw the major product that is obtained when (2S,3S)-2-Bromo-3-phenylbutane is treated with sodium ethoxide.

Answers

Answer:

Explanation:

The mechanism of the reaction is shown in the diagram below. From the reaction, when (2S,3S)-2-Bromo-3-phenylbutane undergoes a reaction with sodium ethoxide (ETONa), the E2 elimination reaction is put into place. Here, the H and the leaving group are antiperiplanar to one another and the reaction mechanism proceeds to form an isomeric (E)-2-phenyl-2butane as the major product.

Why do gases act more ideal at
lower pressures?

Answers

Answer:

Gases act more ideal at lower pressure beacuse the attractive forces between molecules will decrease or become less significant compared to the empty space between them.

Explanation:

Generally, a gas behaves more like an ideal gas at higher temperature and lower pressure as the potential energy due to intermolecular forces becomes less significant compared with the particles "kinetic energy" and the size of the molecules become less significant compared to the empty space between them.

Attractive forces between molecules, decrease the pressure of a reak gas, slowing the molecules and reducing collisions with the walls.The higher the value of a gas, the greater the attraction between molecules and the more easily the gas will compress.

HOPE IT HELPS MUCH

answered by: John Glenly Pillazo Mahusay

1 or 2 topics or two lessons should be explained in an illustrated childrens book minimum of 10 pages must have 3 or more sentences

Answers

Answer:

Yes because same topic are long

¿soy guapo?
si dices que si te doy una galletita

Answers

Answer:

Hindi ko po ma gets sinasabi nyu pwedeng pakiayus

Chrehtegv ittgger ok so eva

When sodium chloride, NaCl , dissolves in water, the solution contains ___________________ in addition to the water solvent. The partial charges in water help dissolve the compound as the hydrogen end of water is attracted to the ____________ and the oxygen end is attracted to the _______________

Answers

Answer:

sodium ions and chloride ions

chloride ion

sodium ion

Explanation:

Ionic substances are composed of ions. When you dissolve an Ionic substance in water, the ions that compose the substance together with water molecules are present in solution.

Hence, when sodium chloride is dissolved in water, sodium ions and chloride ions are released in solution.

Water has a dipole moment. Hence, the chloride ions are attracted to hydrogen (the positive end of the dipole) while sodium ions are attracted to oxygen (the negative end of the dipole).

This is how the solid is dissolved in water.

When sodium chloride, NaCl , dissolves in water, the solution contains sodium and chloride ions in addition to the water solvent. The partial charges in water help dissolve the compound as the hydrogen end of water is attracted to the chloride ions and the oxygen end is attracted to the sodium ions.

What molecules are soluble in water?

Those molecules in which positive ion as well as negative ion is present, will show solubility in water.

Sodium chloride (NaCl) is an ionic compound, which dissociates into sodium ion and chloride ion in the water. As in the water H⁺ ions are present which get attracted towards the chloride ions (Cl⁻) and hydroxide ion (OH⁻ ion) get attracted towards the sodium ions (Na⁺) and show complete dissolution.

Hence correct answers are sodium and chloride ions, chloride ion and sodium ion.

To know more about solubility in water, visit the below link:
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Give the name of the molecular compound and the name of the aqueous solution for each of the binary compounds below.

a. HCN
b. HF
c. H2S

Answers

Explanation:

A compound containing only two elements is called a binary compound.

(a). The compound HCN contains a hydrogen ion and cyanide ion. Hence, the name of HCN is hydrogen cyanide.

An aqueous solution of hydrogen cyanide is known as hydrogen cyanide solution.

(b). The compound HF contains a hydrogen ion and a fluorine ion. The suffix -ide will be added to its name. So, the name of this compound is hydrogen fluoride.

An aqueous solution of HF is known as hydrogen fluoride.

(c). The compound [tex]H_{2}S[/tex] contains two hydrogen atoms and one sulfur atom. The suffix -ide will be added to its name. So, the name of this compound is hydrogen sulfide.

An aqueous solution of this compound is known as hydrogen sulfide solution.

Water has a density of 1.00 g/mL. If you put an object that has a density of 0.79 g/mL into water, it will sink to the bottom.
ANSWER please
True
False

Answers

Answer:

False

Explanation:

An object with a density less than the density of water will float.

And an object that is denser than water (more than 1.00g/mL) will sink when placed in water.

when (S)-3-bromo-2,3-dimethylpentane is treated with sodium chloride with water as the solvent, the products formed are ___________. *Select all that apply

Answers

Answer:

(S)-3-chloro-2,3-dimethylpentane

Explanation:

When sodium chloride is treated with bromo dimethylpentane in presence of water, then chloro dimethylpentane is formed. This chemical reaction is stable reaction in water because of its solvency.

Construction of battery cells

Answers

Answer:

These batteries are constructed of several single cells connected in series each cell produces approximately 2.1 volts. ... A battery cell consists of two lead plates a positive plate covered with a paste of lead dioxide and a negative made of sponge lead, with an insulating material (separator) in between.

if salt and sand is mixed with distilled water, what will be the residue? and, what will be the filtrate?

Answers

Answer:

Filtration is a technique used as a remedy to separate mixes

Explanation:

If you have a sodium, then you will explore that salt dissolves but the sand is still the same.

If the salt in the resin water solution scanners, the sand remains the residue and passes through the filter paper.

All you have to do now is pleasant the salty water so that the water can evaporate, leaving the salt behind.

You are stowing items and come across an aerosol bottle of hairspray. What should you do? Please choose all that apply

Answers

Answer:stow the hairspray

Explanation:

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