A certain substance X has a normal freezing point of −3.1°C and a molal freezing point depression constant =Kf·6.23°C·kgmol−1. Calculate the freezing point of a solution made of 12.3g of urea NH22CO dissolved in 300.g of X. Be sure your answer has the correct number of significant digits.

Answers

Answer 1

Answer:

Freezing T° of solution =  - 7.35 °C

Explanation:

This is about the freezing point depression, a colligative property which depends on solute.

The formula is: Freezing T° pure solvent - Freezing T° solution = m . Kf . i

Freezing T° of pure solvent is -3.1°C

At this case, i = 1. As an organic compound the urea does not ionize.

We determine the molality (mol/kg of solvent)

We convert mass to moles:

12.3 g . 1mol / 60.06 g = 0.205 moles

0.205 mol / 0.3 kg = 0.682 mol/kg

We replace data in the formula:

-3.1°C - Freezing T° of solution  = 0.682 mol/kg . 6.23 kg°C/mol . 1

Freezing T° of solution = 0.682 mol/kg . 6.23 kg°C/mol . 1 + 3.1°C

Freezing T° of solution =  - 7.35 °C


Related Questions

What are the similarities and differences between a crystal of molecules and a polymer?

Answers

Ok so both are cases where molecules pack together in an orderly fashion. In crystals, molecules pack together in any direction. The molecules are not chemically bonded together. In polymers, long chains of the same molecule are chemically bonded together.

The similarities between crystal of molecules and polymers are;

Both are are composed of regular repeating units of moleculesBoth can be arranged in a definite pattern to give a solid material

Differences between a crystal of molecules and a polymer are;

Polymers result from long chains of molecules while crystal of molecules results from the aggregation of a fewer number of molecules.molecules polymers are held together by chemical bonds while molecules in crystal of molecules are held together by weak inter-molecular forces.

Many molecules occurs as crystals. These crystals of molecules have a well defined shape and are composed of a regular repeating unit of molecules not held together by chemical bonds.

Polymers are formed from small molecules called monomers which are arranged in a regular repeating manner to form macro-molecular structures which sometimes have a high tensile strength.

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According to Democritus, what is the composition of matter?

Answers

Answer:

he composition of matter is invisible particles called atoms.

Explanation:

I'm sure its correct

Answer:

The composition of matter is invisible particles called atoms. ... The root of the word "atom" is atomos, meaning uncuttable.

From Google

Hope I Helped

5400 L to KL
With work??

Answers

Answer:

5.4KL

Explanation:

Divide by 1000

Which is the formula mass of (NH4)2SO4?
0 96.07 amu
114.12 amu
O 116.17 amu
132.17 amu

Answers

Answer:

D. 132.17 amu

Explanation:

The formula mass of a compound can be determined from the formula of the compound thus, from the number each elements present. The formula mass of (NH₄)₂SO₄ is 132.17 amu.

What is formula mass?

Formula mass of a compound is the mass calculated from its formula. Each elements has a definite mass called its atomic mass expressed in g/mol or amu.

Mass number of an element is the sum of number of its protons and neutrons. The actual mass of an element is calculated with respect to the mass of 1/12th of Carbon-12 and it is called relative mass.

Here, the atomic mass of N = 14.006 amu

                        mass of H = 1.008 amu.

There are 4 hydrogen thus 4 × 1.008 = 4.008 u.

The mass of two units of  NH₄ is = (14.006 + 4.008) × 2

                                                      = 36.028 u.

Atomic mass of sulfur = 32.6 amu

atomic mass of oxygen = 15.9 amu.

Thus for 4 oxygens = 15.9 × 4 =  63.6 u

The mass of SO₄ unit = 32.06 + 67.6 = 96.2u

Thus the total mass of (NH₄)₂SO₄ = 96.2 + 36.028

                                                        = 132.17 amu

Hence, the formula mass of (NH₄)₂SO₄ is 132.17 amu. Thus, option D is correct.

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Give two real life applications of chromatography

Answers

Answer:

Food testing.

Beverage testing.

Drug testing.

Forensic testing.

Answer:

1. Additive detection

2. Crime scene testing

Question 1 (Multiple Choice Worth 2 points)
(01.01 LC)
The strength of gravitational force is affected by the distance between objects and which of the following?
O Weight
O Speed
O Density
O Mass

Answers

Answer: the answers is mass

An element is an arrangement of atoms in a particular way; True or False?

Answers

Answer:

i think it's true because An element is a substance that is made entirely from one type of atom

Help me please, i’d appreciate it a lot! thank you!❤️

Answers

Explanation:

think so it is useful and sufficient for your question

Why are alkalis sometimes
described as the opposite of
acids?

Answers

Answer: Because Alkalis are bases that can dissolve in water, which can also neutralize acid.

Which term describes the energy an object has because of its motion?

Answers

kinetic energy (the energy of motion)

Answer:

kinetic

Explanation:

100.0 mL of a 0.500 M solution of KBr is diluted to 500.0 mL. What is the new concentration of the solution

Answers

Answer:

0.1 M

Explanation:

The following data were obtained from the question:

Initial volume (V1) = 100 mL

Initial concentration (C1) = 0.5 M

Final volume (V2) = 500 mL

Final concentration (C2) =?

Using the dilution formula C1V1 = C2V2, the new concentration of the solution can be obtained as follow:

C1V1 = C2V2

0.5 × 100 = C2 × 500

50 = C2 × 500

Divide both side by 500

C2 = 50/500

C2 = 0.1 M

Therefore, the new concentration of the solution is 0.1 M

The new concentration of the solution of KBr that was diluted to 500mL is 0.1M

HOW TO CALCULATE CONCENTRATION:

The concentration of solution that was diluted can be calculated using the formula as follows:

C1V1 = C2V2

Where:

C1 = original concentration (M)C2 = diluted concentration (M)V1 = original volume (mL)V2 = diluted volume (mL)

According to this question, 100.0 mL of a 0.500 M solution of KBr is diluted to 500.0 mL. The new concentration can be calculated as follows:

0.500 × 100 = C2 × 500

50 = 500C2

C2 = 50 ÷ 500

C2 = 0.1M

Therefore, the new concentration of the solution of KBr that was diluted to 500mL is 0.1M.

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You estimate that you sent 135 texts last week but when you get the bill, it was actually 175. Calculate the percent error

Answers

Answer: -40

Explanation: Percent error is calculated by subtracting the value you actually recieved from the literature value (175 in your case)  SO your answer should be 135-175=-40.

Give two examples of rocks composed of only one material.

Answers

Answer:

pyroxenite, quartzite, dunite (over 90% olivine), anorthosite (over 90% plagioclase feldspar), marble, chalk, gypsum

Explanation:

The value of ΔG°′ΔG°′ for the conversion of glucose-6-phosphate to fructose-6-phosphate (F6P) is +1.67 kJ/mol+1.67 kJ/mol . If the concentration of glucose-6-phosphate at equilibrium is 2.95 mM2.95 mM , what is the concentration of fructose-6-phosphate? Assume a temperature of 25.0°C25.0°C .

Answers

Answer:

The concentration of fructose-6-phosphate is 1.50x10⁻³M

Explanation:

Gibbs Free energy, ΔG°, is defined as:

ΔG° = -RTln K

Where ΔG° = 1670J/mol

R is gas constant = 8.314J/molK

T is absolute temperature (25°C + 273.15 = 298.15K)

Thus, equilibrium constant, k, is:

1670J/mol = -8.314J/molK* 298.15K ln K

-0.6737 = ln K

0.5098 = K

K of the reaction:

G6P ⇄ F6P

is:

K = 0.5098 = [F6P] / [G6P]

As [G6P] is 2.95x10⁻³M:

0.5098 = [F6P] / [2.95x10⁻³M]

[F6P] = 1.50x10⁻³M

The concentration of fructose-6-phosphate is 1.50x10⁻³M

example for Conceptual

Answers

Answer:

The definition of conceptual is something having to do with the mind, or with mental concepts or philosophical or imaginary ideas. An example of conceptual is when you formulate an abstract philosophy to explain the world which cannot be proven or seen. "Conceptual."

Explanation:

In an atom of an element there are a fixed number of electrons. If the total mass of electrons in 1 mole (6.022 x 1023) of atoms of a certain element is 18.65 mg, how many protons must there be in the nucleus of that atom? (mass of electron = 9.109 x 10–28 g).

Answers

Answer:

No. of protons = 34

Explanation:

First we need to calculate the number of electrons in one mole of the the element:

No. of electrons per mole = Total Mass of Electrons/Mass of 1 Electron

No. of electrons per mole = (18.65 x 10⁻³ g)/(9.109 x 10⁻²⁸ g)

No. of electrons per mole = 2.04 x 10²⁵ electrons/mol

Now, we calculate the no. of electrons in 1 atom:

No. of electrons per atom = No. of Electrons per mole/No. of atoms per mole

No. of electrons per atom = (2.04 x 10²⁵ electrons/mol)/(6.022 x 10²³ atoms/mol)

No. of electrons per atom = 34 electrons/atom

Since, the no. of protons in a pure element are equal to the number of electrons. Therefore,

No. of protons = 34

In this exercise we have to use the knowledge of atoms to calculate the number of protons, in this way we find:

Protons will be  34

First we need to reckon the number of electrons fashionable individual blemish of the the place where one feels comfortable:

[tex]electrons \ per \ mole = Total\ Mass\ of \ Electrons/Mass\ of\ 1 \ Electron\\ electrons\ per\ mole = (18.65 * 10^{-3} g)/(9.109 * 10^{28} g)\\ electrons \ per \ mole = 2.04 x 10^{25} electrons/mol[/tex]

Now, we plan on the electrons in 1 smallest part of something:

[tex]electrons\ per\ atom = Electrons\ per\ mole/atoms\ per\ mole\\ electrons\ per\ atom = (2.04 * 10^{25} electrons/mol)/(6.022 * 10^{23} atoms/mol)\\ electrons\ per\ atom = 34 electrons/atom [/tex]

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The density of an element is 11.3 g/cm'. What is its density in kg/mº? ​

Answers

Answer:

11.3 g/cm³ = 11.3x100x100x100/ 1000 = 11300kg/m³

Explanation:

Choose the answer that shows the following number correctly
written in scientific notation.
430,000
a 4.3 x 104
b 43 x 104
C 0.43 x 106
d 4.3 x 105

Answers

D) 4.3 x 10^5 is the answer

Brainliest?

2. Report each of the following quantities to 3 significant figures. Use standard notation if possible, or
exponential notation if standard notation won't work.
a. 86,942
f. 56,018
b. 0.00621875
g. 0.003870
c. 107062.03
h. 15.9994
d. 4.00049
i. 12.011
e. 96
j. 2,000

Answers

Answer:

a. 86,942  = 8.69x10⁴

f. 56,018  = 5.60x10⁴

b. 0.00621875  = 6.22x10⁻³

g. 0.003870  = 3.87x10⁻³

c. 107062.03  = 1.07x10⁵

h. 15.9994  = 16.0

d. 4.00049  = 4.00

i. 12.011  = 12.0

e. 96  = 9.60x10¹

j. 2,000 = 2.00x10³

Explanation:

Hello,

In this case, rounding off each measurement to three significant figures, considering that if the fourth figure is five or more, the third one is rounded, we obtain:

a. 86,942  = 8.69x10⁴ (four places until the last digit and third digit is not rounded).

f. 56,018  = 5.60x10⁴ (four places until the last digit and third digit is not rounded).

b. 0.00621875  = 6.22x10⁻³ (three places until the first digit and third digit is rounded).

g. 0.003870  = 3.87x10⁻³ (three places until the first digit and third digit is not rounded).

c. 107062.03  = 1.07x10⁵ (five places until the last non-decimal digit and third digit is not rounded).

h. 15.9994  = 16.0 (those consecutive nines round the number to 16.0).

d. 4.00049  = 4.00

i. 12.011  = 12.0

e. 96  = 9.60x10¹ (exponential notation is needed since the number initially has two significant figures so an additional zero is added)

j. 2,000 = 2.00x10³ (three places until the last digit and third digit is not rounded).

Best regards.

Was the french revolution driving force behind the metric system?

Answers

Answer:

yes, they were

Explanation:

The history of the metric system began in the Age of Enlightenment with notions of length and weighttaken from natural ones, and decimal multiples and fractions of them. The system became the standard of France and Europe in half a century. Other dimensions with unity ratios[Note 1] were added, and it went on to be adopted by the world.

If the chemical reaction AB + CD ⟶ AD + BC releases heat, what is true of the stored bond energy of the reactants and products? The bonds do not have energy, the atoms release heat. The bond energy of the reactants is the same as the bond energy of the products. The bond energy of the reactants is lower than the bond energy of the products. The bond energy of the reactants is higher than the bond energy of the products.

Answers

Answer:

The correct option is the last option

Explanation:

The chemical reaction provided in the question is a double-displacement reaction which is an exothermic reaction (which is the reason for the release of heat). An example of a double displacement reaction and exothermic reaction is the neutralization reaction illustrated below.

HCl + NaOH ⇒ NaCl + H₂O

From the law of conservation of energy, energy can neither be created nor destroyed, hence the total energy in a given system should ordinarily be the same (in the reactants and products), however when energy is released in a reaction (as in the case with an exothermic reaction), it shows there are more bond energy in the reactants than in the products and it is the excess energy that is been released into the atmosphere.

(01.04 LC)
What phase of matter has particles that are held together but can flow past each
other and takes the shape of a container, filling it from the bottom up? (3 points)
1) Gas
2) Liquid
3) Plasma
4) Solid

Answers

the answer is liquid ! hope this helped :)

A decomposition occurs when you open a can or bottle of soda. Carbonic acid,H2CO3, is in carbonated beverages. It decomposes into carbon dioxide and water. If you leave an open soda can out for a long time, it loses its fizz. Which equation represents the balanced chemical equation for this reaction?

Answers

Answer:

H₂CO₃ (aq) → CO₂ (g) + H₂O (l)

Explanation:

Step 1: Write out unbalanced decomposition equation

H₂CO₃ (aq) → CO₂ (g) + H₂O (l)

Step 2: Balance equation

We see that we have 3 oxygens on both sides of the reaction.

We also see that we have 1 carbon on both sides of the reaction.

We also see that we have 2 hydrogens on both sides of the reaction.

Therefore, the chemical equation is balanced.

what are we referring to when we talk about the position of an object​

Answers

Explanation:

The location of a body with reference to a given point.

The element X has three naturally occurring isotopes. The isotopic masses (amu) and % abundances of the isotopes are given in the table below. Calculate the average atomic mass of the element in amu. PLEASE HELP ASAP THANK YOU SO MUCH

Answers

Answer:

162.35 amu

Explanation:

Let A represent isotope X-159

Let B represent isotope X-163

Let C represent isotope X-164

The following data were obtained from the question:

Isotope >>> Abundance >>> Mass no

A >>>>>>>> 30.60 >>>>>>>> 159.37

B >>>>>>>> 15.79 >>>>>>>>> 162.79

C >>>>>>>> 53.61 >>>>>>>>> 163.92

Average Atomic mass =.?

The average atomic mass of element X can be obtained as follow:

Average atomic mass = [(mass of A × A%)/100] + [(mass of B × B%)/100] + [(mass of C × C%)/100]

= [(159.37 × 30.60)/100] + [(162.79 × 15.79)/100] + [(163.92 × 53.61)/100]

= 48.77 + 25.70 + 87.88

= 162.35 amu

Therefore, the average atomic mass of element X is 162.35 amu

Calculate the percent composition for each of the elements in Na3PO4. A 5.00 gram sample of an oxide of lead PbxOy contains 4.33 g of lead. Determine the simplest formula for the compound. Balance the following equations by inspection: Cu(N03)2 rightarrow CuO + NO2 + O2 C2H6 + O2 rightarrow CO2 + H2O Mg3N2 + H2O rightarrow Mg(OH)2 + NH3 Magnesium (Mg) reacts with chlorine gas (C12) to produce magnesium chloride (MgC12). How many grams of Mg will react with 2 moles of Cl2? Mg(s) + C12(g) rightarrow MgC12(s) The compound P4S3 is used in matches. It reacts with oxygen to produce P4O10 and SO2. The unbalanced chemical equation is shown below, P4S3(s) + O2(g) rightarrow P4O10(s) + SO2(g) What mass of SO2 is produced from the combustion of 0.331 g P4S3 in excess O2? Nitric oxide is made from the oxidation of ammonia. What mass of nitric oxide can be made from the reaction of 8.00 g NH3 with 17.0 g O2? 4 NH3(g) + 5 O2(g) rightarrow 4 NO(g) + 6 H2O(g) To what volume should you dilute 50.0 mL of 12 M HNO3 solution to obtain a 0.100 M HNO3 solution?

Answers

Answer:

1. Percentage composition of: Na = 42%; P = 19.0%; O = 39%

2. Simplest formula of compound is PbO₂

3. (i) 2Cu(NO₃) ---> 2CuO + 2NO₂ + 3O₂

(ii) 2C₂H₆ + 7O₂ ---> 4CO₂ + 6H₂O

(iii) Mg₃N₂ + 6H₂O ---> 3Mg(OH)₂ + 2NH₃

4. 48 g of MG will react with 2 moles of Cl₂

5. 0.288 g of SO2 will be  produced from the combustion of 0.331 g P₄S₃ in excess O₂

6. 12.8 g of nitric oxide can be produced from the reaction of 8.00 g NH₃ with 17.0 g O₂

7. The stock acid solution should be diluted to 6000 mL or 6.0 L

Explanation:

The full explanation is found in the attachments below

. A certain medication is set to deliver through an IV at a rate of 3.0 mg/min. What is this rate in mg/s?

Answers

Answer:

[tex]rate=0.05\frac{mg}{min}[/tex]

Explanation:

Hello,

In this case, considering that 1 min equals 60 seconds, we need to perform the unit conversion as shown below in order to compute the rate on mg/s:

[tex]rate=3.0\frac{mg}{min}*\frac{1min}{60s} \\ \\rate=0.05\frac{mg}{min}[/tex]

Best regards.

convert 13.4 degrees celcius into kelvin​

Answers

Answer:

286.55K

Explanation:

To convert to kelvin , add 237 .15

[tex]13.4\°C + 273.15 = 286.55K[/tex]

Answer:

13.4 degrees celsius =

286.55 kelvins

Temperature

13.4

Celsius

286.55

Kelvin

Formula

13.4°C + 273.15 = 286.55K

Explanation:

HOPE THAT HELPS YOU

Which charts or graphs always use axes both labeled with quantitative values and show individual points of data, meaning that each point matches with one value on the x-axis and one value on the y-axis? Check all that apply.

Answers

The graphs which use axes both labeled with quantitative values and show individual points of data include:

Scatter plotsLine graphsBar graphs.

What is a Graph?

Thus is defined as a pictorial representation of data or variables in an organized or definite manner.

The graphs mentioned above always have each point matching with one value on the x-axis and one value on the y-axis.

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What will be the cost of gasoline for a 4,700-mile automobile trip if the car gets 41 miles per gallon, and the average price of gas is $3.79 per gallon?

Answers

Answer:

Idk

Explanation:

Find the gallons needed by dividing total miles by miles per gallon:

4700/41 = 114.634 gallons

Multiply the gallons needed by price per gallon:

114.634 x 2.79 = $319.83 Total

Round the answer as needed.

If gallons were rounded to 115 gallons total cost would be $320.85

Answer:

$ 434.40

Explanation:

41 miles ............ 1 gallon

4700 miles .......x gallon

x = 4700×1/41 = 114.63 gallons

114.63 gallons×$3.79 ≈  $ 434.40

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