The molar mass of a compound can be determined by the freezing point depression method. The solution must be relatively dilute and you must know the molal freezing point depression constant of the solvent, Kf. Which statement regarding Kf is true?
A. Kf should be small so that the solvent will not sublimate.
B. Kf will change depending on what solute is dissolved in the solvent.
C. Kf should be negative so the freezing point of the solution will decrease.
D. Kf should be large so the temperature change will be large enough to measure.

Answers

Answer 1

Answer:

K should be large so the temperature change will be large enough to measure.

Explanation:

Let us recall that;

∆T = k m I

Where;

∆T= change in boiling point

K= freezing point constant

m= molality

i= Van't Hoff factor

Since the change in temperature depends on k, the larger the value of k the larger the temperature change(Ts - Tb). Hence; K should be large so the temperature change will be large enough to measure.

Ts= freezing temperature of pure solvent

Tb= freezing temperature of solution


Related Questions

Using the following equation for the combustion of octane calculate the heat associated with the formation of 100.0 g of carbon dioxide. The molar mass of octane is 114.33 g/mole.

2C8H18 + 25O2 → 16 CO2 + 18 H2O

ΔH°rxn = -11018 kJ

Answers

Answer:

The right solution is "-602.69 KJ heat".

Explanation:

According to the question,

The 100.0 g of carbon dioxide:

= [tex]\frac{100.0 \ g}{114.33\ g/mole}[/tex]

= [tex]0.8747 \ moles[/tex]

We know that 16 moles of [tex]CO_2[/tex] formation associates with -11018 kJ of heat, then

0.8747 moles [tex]CO_2[/tex] formation associates with,

= [tex]-\frac{0.8747}{16}\times 11018 \ KJ \ of \ heat[/tex]

= [tex]-0.0547\times 11018[/tex]

= [tex]-602.69 \ KJ \ heat[/tex]

What is the concentration of Htions at a pH = 11?
mol/L
What is the concentration of Htions at a pH = 6?
mol/L
How many fewer Htions are there in a solution at a
pH = 11 than in a solution at a pH = 6?

Answers

Answer:
a) 1 x 10^-11 mol/L
b) 1 x 10^-6 mol/L
c) 1 x 10^-5 fewer H+ ions

Explanation

pH stands for Power of Hydrogen, the more acidic a substance is, the more H+ ions it has rendering the substance acidic. a pH of 1 means the concentration of H+ ions is 1 x 10^-1. A pH of 7 means the concentration of H+ ions is 1 x 10^-7 and so on.

10^-11 has 10^-5 more H+ ions than 10^-6

Hope this helps :)

name two device that are using spinning​

Answers

Two device that are using spinning

Takli

Takli is a small support style spindle. Takli is a perfect tool for spinning cotton, and this are used too to spin fibers, cotton, cashmere, and silk etc. Takli is known as handspindle. And it is the simplest device for spinning.

Charkha

Charkha is a device for spinning thread or yarn from fibers etc. This are known as spinning wheel.

HAVE A NICE DAY!

The freezing point of a substance is -20°C. Its boiling point is 120°C.
a. At 80°C the substance is in the state
b. At -50°C the substance is in the state.
C. At 140°C the substance is in the state.

Answers

Answer:

a. liquid

b. solid

c. gas, (should be at it's boiling point)

Explanation: If the normal melting point of a substance is below room temperature, the substance is a liquid at room temperature. Benzene melts at 6°C and boils at 80°C; it is a liquid at room temperature. If both the normal melting point and the normal boiling point are above room temperature, the substance is a solid.

if you need an explanation to each lmk

When equal moles of an acid and a base are mixed, after reaction the two are compounds are said to be at the _______________. Select one: Indicator point Stoichiometric point Equilibrium point End point

Answers

Answer:

when equal moles of an acid and base are mixed,after reaction the two are compounds are said to be at the Equivalent point.

What does this graph show about the acceleration of the moving object?

the acceleration is constant
the object is not accelerating
the acceleration is decreasing
the acceleration is increasing

Answers

Answer:

the accleration is decreasing

Explanation:

I hpe so

Answer:

the acceleration is increasing

Explanation:

I took a test with a question that was phrased like this, so I'm assuming (hoping) that it's the same graph

When the equation,
O2 + __C 10H 22 →
CO2 +
H2O is balanced, the coefficient of O2 is?

Please help!

Answers

(10)O_2+C_10 H_22-->(10)CO_2+(11)H_2 O

This is the correct balanced equation

The coefficient would be (20) when you multiply 10 by 2

A bio catalyst that increases the rate of the reaction without being changed
a) Aluminum oxide. b) Silicon dioxide. c) Enzyme. d) Hydrogen peroxide
43. What is the
than the reaction substrate.
42. A

Answers

Explanation:

Enzymes are proteins functioning as catalysts that speed up reactions by lowering the activation energy. A simple and succinct definition of an enzyme is that it is a biological catalyst that accelerates a chemical reaction without altering its equilibrium.

The element europium exists in nature as two isotopes: has a mass of u and has a mass of u. The average atomic mass of europium is u. Calculate the relative abundance of the two europium isotopes.

Answers

Answer:

Problem Details

The element europium exists in nature as two isotopes:  151Eu has a mass of 150.9196 amu, and 153Eu has a mass of 152.9209 amu. The average atomic mass of europium is 151.96 amu. Calculate the relative abundance of the two europium isotopes.

answer:

151Eu = 48%, 153Eu = 52%

Which of the following best describes physical science?
0...
OA.
the study of motion
OB.
the study of matter and energy
O C.
the study of Earth's structure and processes
OD.
the study of reactions
O E.
the study of living things
Reset
Ne

Answers

B. The study of matter and energy.

Because physical science is everything that doesn't include organic things.

The  study of matter and energy among the following  best describes physical science.

What is matter?

Matter in chemistry, is defined as any kind of substance that has mass and occupies space that means it possess volume .Matter is composed up of atoms which may or not be of same type.

Atoms are further made up of sub atomic particles which are the protons ,neutrons and the electrons .The matter can exist in various states  of substances such as solids, liquids and gases depending on the conditions of  the temperature and  the pressure.

The states of matter are inter convertible into each other by changing the parameters of temperature and pressure.Matter is always conserved by law of conservation of matter.The law was proposed by Antoine Lavoisier.

Learn more about matter,here:

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s-Block compounds give a characteristic flame colour in the flame test. Based on this, can you give one use of s-block compounds?​

Answers

Answer:

Lithium is used in making electrochemical cells.

Based on the following observations decide the order of reactivity for hydrogen, magnesium, and copper. Hydrochloric acid reacts with magnesium but did not react with copper. magnesium reacted with copper sulfate. Write your answers in the blanks. For magnesium write magnesium for hydrochloric acid write hydrogen and for copper sulfate write copper.

Answers

Answer:

Mg> H> Cu

Explanation:

We can see from the question that hydrochloric acid reacted with magnesium as follows;

Mg(s) + 2HCl(aq) ----> MgCl2(aq) + H2(g)

Copper does not react with HCl which means that copper is less reactive than hydrogen hence it can not displace hydrogen from a dilute acid solution.

The order of reactivity of the elements then is ; Mg> H> Cu

Explain why
when suger
is heated it
does not boil but rather break down
into carbon and water?

Answers

Answer:

When simple sugars such as sucrose (or table sugar) are heated, they melt and break down into glucose and fructose, two other forms of sugar. Continuing to heat the sugar at high temperature causes these sugars to lose water and react with each other producing many different types of compounds.

……….is strong due to the ……………..between positive ions and negative delocalized electrons

Answers

Answer:

atom &bond

Explanation:

atom is strong due to the bond

CH3CH2OH
______ions
in an aqueous solution.
А
forms
B
does not form

Answers

Answer:

When ionic compounds dissolve, they break apart into ions which are then able to conduct a current ( conductivity ). ... Many molecular compounds, such as sugar or ethanol, are nonelectrolytes. When these compounds dissolve in water, they do not produce ions.

Explanation:

Ethanol is an organic compound with an alcoholic functional group and is nonelectrolytes. Ethanol (CH₃CH₂OH) does not form ions in an aqueous solution. Thus, option B is correct.

What are nonelectrolytes?

Nonelectrolytes are substances that do not dissociate readily to yield ions and also are poor conductors of electricity and heat due to a lack of charged ions.

Ethanol is a nonelectrolyte that does not show conductivity and can be dissolved in water without producing ions. They cannot forms ions upon dissociation as covalent bonds are present.

Instead of ions that have covalent compounds that lack the ability to transfer the electron to conduct the electrical charge. Glucose, ethanol, etc. are some examples of a nonelectrolyte.

Therefore, option B. ethanol does not form ions is the correct blank.

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Determine which choice is an example of an endothermic process.
O A. Lighting a match
B. Respiration
C. Running a gas engine
D. Baking bread

Answers

Answer:

D. Baking bread

Explanation:

In this process, energy is absorbed and in an endothermic process energy is absorbed too.

Baking bread is an example of an endothermic process, therefore option (d) is correct .

What do you mean by endothermic process ?

Endothermic reactions are chemical processes in which the reactants absorb heat from the environment to produce products.

An endothermic reaction is  accompanied by an absorption of heat.

Endothermic  reactions cause a cooling effect by lowering the temperature of the surrounding environment.

A decrease in temperature can be observed with the progression of the reaction. The reaction is non-spontaneous in endothermic reactions .

Baking bread is an example of an endothermic process, hence  option (d) is correct .

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1. Metallic strontium crystallizes in a face-centered cubic lattice, with one Sr atom per lattice point. If the edge length of the unit cell is found to be 608 pm, what is the metallic radius of Sr in pm?
2. The substance beta manganese is found to crystallize in a cubic lattice, with an edge length of 630.0 pm. If the density of solid beta manganese is 7.297 g/cm3, how many Mn atoms are there per unit cell?

Answers

Answer:

[tex]r=215pm[/tex]

[tex]N_{Mn}=20[/tex]

Explanation:

From the question we are told that:

Edge length of the unit cell [tex]l=608pm[/tex]

a)

Generally the equation for The relationship between edge length and radius is mathematically given by

[tex]4r=\sqrt{2a}[/tex]

Therefore

[tex]4r=\sqrt{2*608}[/tex]

[tex]r=\frac{\sqrt{2*608}}{4}[/tex]

[tex]r=215pm[/tex]

b)

From the question we are told that:

Density [tex]\rho=7.297[/tex]

Edge length of [tex]l=630.0 pm=>630*10^-{10}[/tex]

Therefore Volume  is given as

[tex]V=l^3[/tex]

[tex]V=630*10^-{10}^3[/tex]

[tex]V=2.50047*10^{−22}[/tex]

Generally the equation for Mass is mathematically given by

[tex]m=Volume*density[/tex]

[tex]m=V*\rho[/tex]

[tex]m=2.50047*10^{−22}*7.297[/tex]

[tex]m=1.83*10^{-21}g[/tex]

Therefore Molarity is given as

[tex]n=\frac{M}{Molar M}[/tex]

[tex]n=\frac{1.83*10^{-21}g}{55}[/tex]

[tex]n=3.32*10^{-23}[/tex]

Finally The atoms in a unit cell is

[tex]N_{Mn}=Moles*Avogadro\ constant[/tex]

[tex]N_{Mn}=3.32*10^{-23}*6.023*10^{23}[/tex]

[tex]N_{Mn}=20[/tex]

Can steel turn into gas? ( A random question that came to mind. I have no idea if it is or isn't possible.)

Answers

Answer:

YES STEEL CAN TURN INTO GAS .

Answer: yes it can!

Explanation:

A/An is a type of blood cell that's also called a red blood cell. a) Jeukocyte O b) thrombocyte c) plasma d) erythrocyte

Answers

Answer:

option a

Explanation:

pls mark me as brainliest

At what velocity (m/s) must a 20.0g object be moving in order to possess a kinetic energy of 1.00J

Answers

Answer:

10 ms-1

Explanation:

Kinetic energy = 1/2 × m × v^2

1 = 1/2× 20 ×10^ -3 × v^2

v ^ 2 = 100

v = 10 ms-1

note : convert grams in to kg before substitution as above

The velocity will be "10 m/s".

Given:

Kinetic energy,

K.E = 1.00 J

Mass,

m = 20.0 g

We know the formula,

→ [tex]K.E = \frac{1}{2} mv^2[/tex]

By putting the values, we get

       [tex]1 = \frac{1}{2}\times 20\times 10^{-3}\times (v)^2[/tex]

     [tex]v^2 = 100[/tex]

       [tex]v = \sqrt{100}[/tex]

       [tex]v = 10 \ m/s[/tex]

Thus the above response is correct.

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Could someone please help me out???

Answers

Answer:

Time is 2.2 seconds.

Explanation:

Time:

[tex]{ \boxed{ \bf{time = \frac{distance}{speed} }}}[/tex]

Substitute into the formula:

speed = 715 km/h = 198.61 m/s

[tex]{ \tt{time = \frac{435}{198.61} }} \\ { \tt{time = 2.2 \: seconds}}[/tex]

In practice, the second law of thermodynamics means that:

a. Systems move from ordered behavior to more random behavior.
b. Systems move from random behavior to more ordered behavior.
c. Systems move between ordered and random behavior patterns based on temperature.
d. Systems are constantly striving to reach equilibrium.

Answers

Answer:

Systems move from ordered behavior to more random behavior.

Explanation:

Entropy refers to the degree of disorderliness in a system. The second law of thermodynamics can be restated in terms of entropy as follows; “any spontaneous process in any isolated system always results in an increase in the entropy of that system.''(science direct)

According to this law, systems tend towards a more disorderly behaviour (increase in entropy) hence the answer given above.

The mass of an empty crucible was 17.556g. The mass of the crucible and a hydrate was 21.018 g. The mass of the crucible and anhydrous salt (after heating) was 19.641g. A. Calculate the mass of water lost due to heating. B. Calculate the mass percentage of water.

Answers

Answer:

A. 1.377 g

B. 16.5%

Explanation:

To find the water loss, subtract the salt and crucible mass from the hydrate and crucible mass

21.018 - 19.641 = 1.377

To find the water mass percentage, divide the empty crucible mass by the mass of the hydrate and crucible. Then, subtract that number from 1.

17.556 ÷ 21.018 = 0.835284

1 - 0.835284 = 0.164716

If you want to add an extra step, multiply this number by 100 to get the percentage.

0.164716 x 100 = 16.4716

If you dissolve 0.1 mol of formic acid in 1 L of water, ther esulting solution contains 0.004 mol of H₃O+. Based on this information, is formic acid a strong acid, or is it a weak acid?

Please explain!

Answers

In an ideal case, the acid would completely protonate. such an acid would be a strong acid.  Dissociation of Formic acid looks like:

HCOOH + H₂O → COOH⁻ + H₃O⁺

one mole of formic acid should give one mole of Hydronium(H₃O⁺) ions

similarly, 0.1 moles of formic acid should produce 0.1 moles of hydronium ions. but we know that it is not the case, a much lesser amount is actually formed.

Which means that Formic acid did not completely dissociate into COOH⁻ and H⁺ ions.

Hence, Formic Acid is a weak acid

We know

Any acid

Containing carbon is weak Containing no carbon is strong

Formic acid stands for HCOOH

It contains C means dissociation is less .

The dissociation of H+ is less means acidity is less.

Weak acid

Which of the following events takes place in the Kreb entry phase (acetyl COA from pyruvate)?


A). Only CO2 output

B). NAD is reduced, CO2 is released

C). NADH is oxidized, CO2 is released

D). Only NADH is oxidized

E). Only NAD is reduceed

Answers

Answer:

Alphabet C :NADH is oxidized,CO2 is reduced

Entropy, the degree of disorder is related to the number of configurations that a system can adopt. If the entropy of a system is 71.85 J/mole*K, the number of configurations possible for this system is:

(a) 7188
​(b) 9967
​(c) 5665
​(d) 2183

Answers

I personally think it’s c I might be wrong tho

Phosphorylation of enzymes:_______.
a. always increases their activity.
b. generally occurs on Ser, Thr, and/or Tyr side chains and to a lesser extent on the His side chain.
c. is irreversible.
d. is one of only five known covalent forms of regulation.

Answers

Answer:

generally occurs on Ser, Thr, and/or Tyr side chains and to a lesser extent on the His side chain

One of the electron transitions in a hydrogen atom produces infrared light with a wavelength of
8.231 x 10°m. What amount of energy causes this transition?

Answers

A transition occurs when an electron absorbs energy and moves from one energy level to another.

Let us recall the formula;

E = hc/λ

h= planks constant = 6.6 * 10^-34 Js

c = speed of light = 3 * 10^8 ms-1

λ = wavelength =

We can see from the question that the exponent in the value for the wavelength was not properly rendered hence we can not be able to substitute values and obtain a numerical answer for the energy of the infrared radiation.

However, if all the values are properly substituted, then the energy of the infrared radiation can conveniently be obtained.

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Titration of 25.0 mL of an HCl solution of unknown concentration requires 14.8 mL of 0.100 M NaOH. What is the molar concentration of the HCl solution

Answers

M1V1 = M2V2
M1 = 0.100 M NaOH
V1 = 14.8 mL NaOH
M2 = ?
V2 = 25.0 mL HCl

(0.100 M)(14.8 mL) = M2(25.0 mL)

M2 = 0.0592 M HCl

(GIVING BRAINIEST!)
Which of the following compares the rainforest and the tundra environments correctly?

A. A rainforest is hotter than the tundra because it is closer to the equator.
B. A rainforest is less humid than the tundra because of its higher elevation.
C. A tundra has higher temperatures than the rainforest because it receives more
sunshine.
D. A tundra has higher humidity than the rainforest because of its proximity to water bodies.
For Science BTW!

Answers

Answer:

A

Explanation:

A rain forest is hotter than the tundra because it is closer to the equator

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