What are the criteria for purity

Answers

Answer 1

Answer:

melting and boiling points

Explanation:

The technique for determination of melting and boiling points will also be described in this unit. Pure solid and liquid compounds possess sharp melting and boiling points. Therefore, melting and boiling points of a compound


Related Questions

How do I explain this? I'm a little stuck. :/

Answers

Answer:

Not balance.

Explanation:

Chemical equation:

K + Cl₂    →    KCl

The given equation is not balance because there are one potassium and two chlorine atoms on left side of equation while on right side there are one potassium and one chlorine atom present.

Balance chemical equation:

2K + Cl₂    →    2KCl

the equation is balance now because there are two potassium and two chlorine atoms on left side of equation and two potassium and two chlorine atoms are also present on right side.

Pls help will give Brainlist
If a sealed 3.0L container has a pressure of 1.0 atm at 20.0 C and is heated to a temperature of 450. K. What is the pressure inside of the container at this temperature?

Answers

The pressure : 1.536 atm

Further explanation

Same container=same volume⇒the volume is constant

Gay Lussac's Law  

When the volume is not changed, the gas pressure in the tube is proportional to its absolute temperature  

[tex]\tt \dfrac{P_1}{T_1}=\dfrac{P_2}{T_2}[/tex]

P₁=1 atm

T₁=20+273=293 K

T₂=450 K

the pressure :

[tex]\tt P_2=\dfrac{P_1.T_2}{T_1}\\\\P_2=\dfrac{1\times 450}{293}=\boxed{\bold{1.536~atm}}[/tex]

question 13 help i’m timed thx u r loved

Answers

Answer:

178.3 L

Explanation:

178,300/1000

Question 23 (5 points)
What is the wavelength of radiation having a frequency of 4.80 x 1017 s-12
C = av
c= speed of light (3.00 x 108 ms-?)
X = wavelength in meters (m)
V = frequency = waves per second(s)
Show formula set up (2 pt)
Show calculator answer (1pt)
Show correct answer to the correct place with correct units (1 pt)
Use table 3 in data booklet to identify the type of radiation (1 pt)

Answers

Answer:

λ = 6.25 × 10⁻¹⁰ m

x-ray

General Formulas and Concepts:

Speed of Light = Wavelength times Frequency

c = λν

Explanation:

Step 1: Define

C = 3.0 × 10⁸ m/s

ν  = 4.80 × 10¹⁷ Hz (s⁻¹)

λ = unknown

Step 2: Solve for wavelength

3.0 × 10⁸ m/s = λ(4.80 × 10¹⁷ Hz)

λ = 6.25 × 10⁻¹⁰ m

Step 3: Check

We are given 3 sig figs. Follow sig fig rules.

6.25 has 3 sig figs. No changes necessary.

Step 4: Identify

6.25 × 10⁻¹⁰ m is in the x-ray spectrum according the the Electromagnetic Spectrum

In another experiment, the student titrated 50.0mL of 0.100MHC2H3O2 with 0.100MNaOH(aq) . Calculate the pH of the solution at the equivalence point.

Answers

pH=8.87

Further explanation

Reaction

C₂H₄O₂+NaOH⇒CH₃COONa+H₂O

at the equivalence point = mol C₂H₄O₂= mol NaOH

mol C₂H₄O₂ : 50 x 0.1 = 0.5 mlmol=5.10⁻⁴ mol

The two reactants have completely reacted, and there is only salt(CH₃COONa) and water(H₂O), there will be hydrolysis

For acids from weak acids and strong bases (the solution is alkaline) then the calculation:

[tex]\tt [OH^-]=\sqrt{\dfrac{Kw}{Ka}\times M }[/tex]

M=anion concentration=CH₃COO⁻

Ka=acid constant(for CH₃COOH,Ka=1.8.10⁻⁵)

[tex]\tt [OH^-]=\sqrt{\dfrac{10^{-14}}{1.8.10^{-5}}\times 0.1 }[/tex]

[tex]\tt [OH^-]=\sqrt{5.6.10^{-11}}=7.483\times 10^{-6}[/tex]

pOH=6-log 7.483=5.13

pH= 14 - 5.13=8.87

The pH of the solution is the negative log [H] concentration. The pH of the given solution is 8.87 at the equivalence point.

pH:

The given Reaction is:  

C₂H₄O₂+ NaOH ⇒ CH₃COON + H₂O

The pH of the solution can be calculated by,

[tex]\bold{pH = 14 - pOH}[/tex]................1

So first, calculate for pOH

[tex]\bold {pOH = \sqrt {\dfrac {Kw}{Ka} \times M}}[/tex]

Where,

Ka - dissociatioon constant = 50 x 0.1 = 0.5 ml = 5x10⁻⁴ mol

Kw - concentaion water ionic products = [tex]\bold {10^{-14}}[/tex]

M - anion concentration( CH₃COO⁻) = 0.1 M

Put the values in the formula,

[tex]\bold {pOH = \sqrt {\dfrac {\bold {10^{-14}}}{5\times 10^{-4} mol} \times 0.1}}\\\\\bold {pOH = 7.483 \times 10^{-6}}[/tex]

Since the pOH is the negative log of [OH⁻] concentration,

pOH = 6  -ln 7.483

pOH = 5.13

Put the value of pOH in the first equation,

pH= 14 - 5.13

pH = 8.87

Therefore, the pH of the given solution is 8.87 at the equivalence point.

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Which of the following solutions of glucose in water will have the lowest freezing point?
(The molar mass of glucose is 180 g/mol.)

Answers

Answer:

B

Explanation:

Colligative properties are properties that depend on the amount of substance present.

Freezing point is a colligative property hence it depends on the number of moles of the glucose present in solution. The bigger the concentration of the glucose molecules, the greater the freezing point depression. So, the largest freezing point depression is observed for the solution having the highest concentration of glucose.

Earth’s rocks change from one type into another, as described in the rock cycle. TRUE OR FALSE

Answers

This answer would be true

Pls help: What is the net equation for CNO cycle?

Answers

Answer:

The CNO cycle (for carbon–nitrogen–oxygen) is one of the two known sets of fusion reactions by which stars convert hydrogen to helium, the other being the proton–proton chain reaction (pp-chain reaction). Unlike the latter, the CNO cycle is a catalytic cycle.

The pH of an aqueous solution of hydrochloric acid is 2. What is the pH of the solution after the addition of 10 g of sodium chloride?

Answers

Answer:

wala ako alam sagot sorry

give me examples of everyday problems you think involve the green substances copper acetate or copper sulfate.

Answers

Answer: Copper sulfate is also called blue vitriol, Roman vitriol, Salzburg vitriol, blue copperas or bluestone, which is an inorganic or chemical compound comprised of Copper, Sulphur and Oxygen.  It is an odorless crystalline substance, electric blue and highly toxic, which is produced in industries by treating the copper metal with hot concentrated sulfuric acid or treating its oxides with dilute sulfuric acid. It can be produced by slowly leaching low-grade copper ore in air and bacteria may be used to hasten the process.

Before an electrocardiogram is recorded for a cardiac patient, the ECG leads are usually coated with a moist paste containing sodium chloride. What property of an ionic substance such as NaCl is being made use of

Answers

Answer:

The property of the ionic substance utilized is its electrical conductivity

Explanation:

Ionic substances are substances which are composed of electrically charged particles called ions. Sodium chloride, NaCl is ionic substance which is composed of sodium ions, Na⁺ and chloride ions, Cl⁻. These ions are usually held in position in the solid form of these substances. However, in aqueous or molten forms, these ions are free to move about and thus conduct electrical charges around.

In an electrocardiogram,  the ECG leads are usually coated with a moist paste containing sodium chloride in order to increase the electrical conductivity between the patient's skin and the electrodes because the sodium chloride will dissociate into chloride and sodium ions and are ths, able to conduct electricity.

What is the symbol for tin on the periodic table
and how many protons does it have?

Answers

Answer:

Symbol for tin- Sn

No. of protons =50

Explanation:

Hope this helps you

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Branches are thrown into a wood chipper and mulch is created. Chemical change or physical change?

Answers

Definitely, a physical change.

What are chemical and physical changes?

A chemical change is a type of change involving the chemical composition of substances. The chemical composition changes completely and lost its old identity.

Chemical changes are unlike physical changes. The latter involves changes to the physical characteristics of substances. The changes do not get to the chemical level.

Thus, chemical changes are ordinarily not reversible but physical changes can be reversed.

When branches are thrown into a wood chipper and mulch is created, a physical change has taken place because the branches can still be recovered from the mulch.

A mulch is just a material layer placed on soils to conserve moisture.

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When purchasing an electrical device, what are the 2 financial costs you need to consider?

Answers

Answer:

How much electricity is uses and any repairs

Explanation:

When purchasing an electrical device, the two financial costs you need to consider are the initial price of the device and the operating costs to make use of the device.

The financial cost is the cost of finance charged per item purchased, it may also include miscellaneous charges associated with the usage of the item.

Here, before you purchase the electrical device, think carefully if:

the initial price fits into your budget and;the consumption of the electricity bills(operating costs) the electrical device will consume.

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Which of the following is TRUE about Nuclear Fusion? A) it causes atoms to separate
B) it is used to produce energy in nuclear power plants C) it is the same way stars and our sun produce energy

Answers

Answer:

B)It is used to produce energy

The nuclear fusion reaction is also called thermonuclear reaction. The true statement is  it is the same way stars and our sun produce energy. The correct option is C.

What is nuclear fusion?

The process in which two lighter nuclei fuse together to form a heavier nucleus with the simultaneous release of a huge amount of energy is defined as the nuclear fusion.

In nuclear fusion some mass is lost and it is converted into energy in accordance with the Einstein's equation, E = mc². This huge amount of energy is released.

The fusion reactions are common in the interior of stars. The energy of our sun is believed to arise from a number of complex fusion steps. This reaction take place only at very high temperatures. The hydrogen bomb also work on the basis of fusion.

Thus the correct option is C.

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The box in the above picture is falling from the top of a building to the ground. Two major forces are acting on the box as it falls. Which force is represented by the arrow labeled Q?
A.
the force of magnetism
B.
the force of gravity
C.
the net force of the object
D.
the force of air resistance

Answers

Answer:

I think it's B

Explanation:

apologies if I get this wrong

Answer:

The correct answer is B. The force of gravity.

Explanation:

Gravity affects all objects falling through the Earth's atmosphere. Gravity pulls down on a falling object.

( I got it on study Island as well )

What is an inorganic chemical?
A. A chemical that contains carbon atoms
B. A chemical that does not take part in reactions
C.A chemical that makes up living things
D.A chemical that is not from living things
I'd appreciate anyone's help

Answers

D ? i think but not sure

Answer:

D.A chemical that is not from living things

please help! An ice cube (25 g) is removed from a freezer at 0 °C. How much energy is required to completely melt the ice cube?

Answers

Answer:

So it takes 80 calories of heat to melt 1 g of an ice cube, now do the math. (Hope this helped)

Explanation:

Pls help
Protons: 4
Neutrons: 4
Electrons: 3
What element is it ?
Boron
Aluminum
Beryllium
Carbon

Answers

Answer:

The answer would be beryllium

You were probably confused but the correct answer would actually be a beryllium ion.

Write the electron configuration for Br, with 35 protons and 35 electrons.

Answers

Answer:

2 8 8 8 8 1

Explanation:

can i has help?

A 2-column table with 7 rows. The first column labeled Material has entries aluminum, iron, lead, sand, steel, wood, water. The second column labeled Specific Heat (Joules per gram times degrees Celsius) has entries 0.90, 0.44, 0.16, 0.83, 0.49, 1.80, 4.18.
Use this chart showing the different specific heat of various materials to answer the questions.

Which material has the highest specific heat?

Which material has the lowest specific heat?

Which material has the ability to absorb twice as much heat as aluminum when placed in the same environment of mass and temperature?

Answers

Answer:

water, lead, and wood

Explanation:

All are correct on Edg 2020

Answer:

Which material has the highest specific heat?

water

Which material has the lowest specific heat?

lead

Which material has the ability to absorb twice as much heat as aluminum when placed in the same environment of mass and temperature?

wood

Explanation:

what is the formula for calculating pH?​

Answers

A. Where the number for the concentration of H+ normally includes: times 10^#. For example, the conc. is given (or determined) as [1.00x10^-5]

Help plz it due in 20 mins

Answers

The answers are: T, T, F, T, T, T

Answer:

True

True

False

True

True

True

Explanation:

What is the average isotope mass?

Answers

Answer:

the atomic mass of an element is the average mass of the atoms of an element measured in atomic mass unit (amu, also known as daltons, D). The atomic mass is a weighted average of all of the isotopes of that element, in which the mass of each isotope is multiplied by the abundance of that particular isotope

Explanation:

Average atomic mass = f1M1 + f2M2 + … + fnMn where f is the fraction representing the natural abundance of the isotope and M is the mass number (weight) of the isotope. The average atomic mass of an element can be found on the periodic table, typically under the elemental symbol.

Answer:

he atomic mass of an element is the average mass of the atoms of an element measured in atomic mass unit (amu, also known as daltons, D). The atomic mass is a weighted average of all of the isotopes of that element, in which the mass of each isotope is multiplied by the abundance of that particular isotope.

The elementary reaction_.

A)converts reactants to products in a single step
B )has only elements as reactants
C )has only elements as products
D) never needs a catalyst

Answers

Answer:

                                                 

Explanation:

                             

A. Converts reactants to products in a single step.

a
Which property of a gas affects the rate at which it spreads throughout
laboratory?​

Answers

Answer:

Diffusion is faster at higher temperatures because the gas molecules have greater kinetic energy. Effusion refers to the movement of gas particles through a small hole. Graham's Law states that the effusion rate of a gas is inversely proportional to the square root of the mass of its particles

Help me out here please?

Answers

Answer:

B

Explanation:

7. Which of the following is always true when a substance undergoes a
phase change? *
O A. The molecules keep moving at the same average speed.
B. The substance becomes a liquid as it heats up.
C. The melting point of the substance changes.
D. The substance is made up of the same type of molecules.

Answers

The following answered has been deleted due to multiple violations to our Terms of Service.

Scientists find a fossil of a fish on top of a mountain. What kind of evidence does the fossil provide scientists about the way this area might have changed over time?



Group of answer choices

It shows that fish were once able to live without water.

It shows that oceans can change quickly and become land.

It shows that the animals found on the mountain today evolved from fish.

It shows that the mountain may have once been under water and was raised by natural processes

Answers

Answer:

It shows that the mountain may have once been under water and was raised by natural processes. Maybe

The fossil provide scientists about the way this area might have changed over time, the evidence It shows that the mountain may have once been underwater and was raised by natural processes.

What is fossil ?

Any surviving remnants, impression, or evidence of a once-living creature from a previous geological epoch is referred to as a fossil. Examples include fossilized bones, shells, exoskeletons, animal or microbe impressions in stone, amber-preserved artifacts, hair, petrified wood, oil, coal, and DNA traces.

There are four basic categories of fossils, each generated in a unique method and useful for conserving various kinds of animals. These include genuine form fossils, trace fossils, mold fossils, and cast fossils.

Usually, sedimentary rocks include fossils, however rarely, low-grade, fine-grained metamorphic rocks will as well. Sometimes, after the fossils have been removed, the surrounding rock has developed molds.

Thus, option D is correct.

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What’s the answer to question 12?

Answers

40 atomic mass units (amu) is the correct answer.
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