g Why must the heating rate be very slow and steady during the determination of melting point

Answers

Answer 1

Explanation:

Determination should be slow (temp rise should not exceed 1C) so that sufficient time may be used to pass thermometer from the heating block equivalent to the sample. If you proceed too quickly, the temperature of the sample differs much from that at the thermometer and the sample seems to have a broad range. Before the thermometer the temperature reaches the sample and the temperature observation is less than predicted.

Remember that an accurate measurement requires a modest heating rate at the melting point. List the thermometer's temperature when the sample begins to melt and again record the temperature when every sample has melt (this gives you the melting point range)


Related Questions

Use the average volume of HNO3 used to calculate the concentration of
NaOH ?

Answers

Answer:

Incomplete question. You didn't give the volume of HNO3

What is the density (in g/L) of hydrogen gas at 21 °C and a pressure of 1670 psi?

Express your answer in grams per liter to three significant figures.

Answers

Answer:

[tex]d=9.5g/L[/tex]

Explanation:

Hello there!

In this case, according to the given information, it i possible for us to calculate the density of this gas via the ideal gas equation, according to the following setup:

[tex]PV=nRT\\\\P=\frac{mRT}{V*MM} \\\\\frac{m}{V}=d=\frac{P*MM}{RT}[/tex]

Thus, we plug in the variables (pressure in atm and temperature in K) to obtain:

[tex]d=\frac{113.6368atm*2.02g/mol}{0.08206\frac{atm*L}{mol*K}*(21+273)K} \\\\d=9.5g/L[/tex]

Regards!

In this image, which fundamental interaction is responsible for attracting the electron?
a. electromagnetism
b. nuclear weak force
c. gravitation
d. nuclear strong force

Answers

Answer:

a.

Explanation:

electromagnetism

The correct answer it (A)

A 2.00 L flask is filled with propane gas (C3H8) at a pressure of 1.10 atm and a temperature of 258 K. What is the mass of propane in the flask?

Answers

Answer:

m = 4.58 g.

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to realize this problem is solved via the ideal gas equation:

[tex]PV=nRT[/tex]

As we can calculate the moles of propane given the pressure, temperature and volume as shown below:

[tex]n=\frac{PV}{RT} \\\\n=\frac{1.10atm*2.00L}{0.08206\frac{atm*L}{mol*K}*258K} \\\\n=0.104mol[/tex]

Finally, since the molar mass of propane is 44.1 g/mol, we calculate the mass by following the shown below mole-mass conversion factor:

[tex]m=0.104mol*\frac{44.1g}{1mol}\\\\m= 4.58g[/tex]

Regards!

What is the equation for the reaction between ethanoic acid and butanol in the presence of H2SO4?

Answers

Answer:

[tex]CH_3COOH+CH_3CH_2CH_2CH_2OH\rightarrow CH_3COOCH_2CH_2CH_2CH_3+H_2O[/tex]

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to realize this is a question about esterification, process whereby a carboxylic acid and an alcohol react to produce water an an ester, we can set it up as shown below:

[tex]CH_3COOH+CH_3CH_2CH_2CH_2OH[/tex]

For the reaction between ethanoic acid and butanol; and therefore, the products side is:

[tex]CH_3COOCH_2CH_2CH_2CH_3+H_2O[/tex]

It means that the overall equation is:

[tex]CH_3COOH+CH_3CH_2CH_2CH_2OH\rightarrow CH_3COOCH_2CH_2CH_2CH_3+H_2O[/tex]

And the ester product is butyl ethanoate.

Regards!

How is the wavelength of an EM wave related to its energy?
O A. The shorter the wavelength of a wave, the higher its energy.
O B. The longer the wavelength of a wave, the less it affects energy.
O C. The shorter the wavelength of a wave, the lower its energy.
O D. The longer the wavelength of a wave, the higher its energy.

Answers

E= hf

so shorter lambda = larger f= more energy

Answer is A

The wavelength of an EM wave related to its energy as "The shorter the wavelength of a wave, the higher its energy".

What are Electromagnetic radiations?

Electromagnetic radiation is a type of energy that is all around us and takes many forms, such as radio waves, microwaves, X-rays and gamma-rays. Sunlight is also a form of electromagnetic energy, but visible light is only a small portion of the electromagnetic spectrum, which contains a broad range of wavelengths.

In order from highest to lowest energy, the sections of the EM spectrum are named: gamma rays, X-rays, ultraviolet radiation, visible light, infrared radiation, and radio waves. In order from highest to lowest wavelength, the series is just opposite.

Electromagnetic radiations don't require any medium to travel and also travel in speed of light. They have Electric field vector and magnetic field vector that is perpendicular to each other and also are perpendicular to the direction of propagation.

Therefore, the wavelength of an EM wave related to its energy as "The shorter the wavelength of a wave, the higher its energy".

Learn more about EM wave, here:

https://brainly.com/question/18729221

#SPJ7

A sample of Oxygen effuses through a porous container about 2 times faster than an unknown gas. Estimate the molar mass of the unknown gas.

Answers

Answer:

The molar mass of the unknown gas is 128g/mol

Explanation:

The rate of effusion of 2 different gases follows the equation:

Rate gas A / Rate gas B = √MM gas B / √MM gas A

Where rate is the speed of effusion of each gas and MM the molar mass of each gas

If gas A is oxygen and gas B the unknown:

Rate gas A / Rate gas B = 2 = √MM gas B / √32g/mol

11.134 = √MM gas B

128g/mol = MM gas B

The molar mass of the unknown gas is 128g/mol

5.40X10^2kj converted into j

Answers

Answer:

540,000 (5.4X10^5)

Explanation:

kj means Kilojoules, while we are converting to joules.

- Kilo, or k, represents our base value, Joules, multiplied by 10^3. To convert to joules, we would simply multiply by 10^3 (which is 1000)

Write out the balanced chemical equation and the net ionic equation for the reaction between hydrochloric acid and sodium hydroxide, using smallest whole number stoichiometric coefficients.

Answers

Answer:

HCl(aq) + NaOH(aq) ⇒ NaCl(aq) + H₂O(l)

H⁺(aq) + OH⁻ ⇒ H₂O(l)

Explanation:

Let's consider the balanced chemical equation (molecular equation) for the reaction between hydrochloric acid and sodium hydroxide. This is a neutralization reaction.

HCl(aq) + NaOH(aq) ⇒ NaCl(aq) + H₂O(l)

The complete ionic equation includes all the ions and the molecular species.

H⁺(aq) + Cl⁻(aq) + Na⁺(aq) + OH⁻ ⇒ Na⁺(aq) + Cl⁻(aq) + H₂O(l)

The net ionic equation includes only the ions that participate in the reaction (not spectator ions) and the molecular species.

H⁺(aq) + OH⁻ ⇒ H₂O(l)

How many grams of chlorine are required in order to consume 100g of sodium chloride?

Answers

Answer:

92.1 g

Explanation:

Answer: 92.1 grams

I hope this helped :3

ch3cooh number of bonding pairs and lone pairs.

Answers

Answer:

whats the question?

Explanation:

Quais são os nomes dos planetas anões

Answers

Answer:

Can you translate it on English so we can understand

from E=mc²=hv show that wavelength=h/mv​

Answers

Explanation:

To show - from E=mc²=hv show that wavelength=h/mv​

Proof -

Given that,

E = mc²

E = hν

By equating both the equations, we get

mc² = hν

Because real particles do not travel at the speed of light, De Broglie submitted velocity ( v ) for the speed of light ( c ).

mv² = hν

Through the equation  λ , de Broglie substituted  v/λ  for  ν  and arrived at the final expression that relates wavelength and particle with speed.

mv² = hv/λ

⇒λ = hv/mv²

⇒λ = h/mv

Hence showed.


8. An ion with 5 protons, 6 neutrons, and a charge of 3+ has an
atomic number of
a) 5
b) 6
c) 8
d) 11

Answers

Atomic number = The number of proton in an atom or ion so the right answer is 5!

(i)What happens when an aqueous solution of sodium sulphate reacts with an aqueous
solution of barium chloride ? (i) Write the balanced chemical equation for the reaction which takes place.(ii) Name the type of chemical reaction which occurs. Define.​

Answers

Explanation:

2nacl+baso4

the orginal equation is

Na2so4+Bacl2

then na react with cl and ba react with so4

Please help answer this Guy's​ HELP it's very Important

Answers

I cant really help you tight now sorry

Please hurry!!! And help!!
*URGENT*
Best answer gets marked Brainliest!

NO LINKS or question will be REPORTED!

Why is elemental zinc considered a pure substance

A) it is a metal

B) it is a mixture of different atoms

C) it must be created in a lab

D) all elements are considered pure substances

Answers

Answer:

D

Explanation:

Answer:

D

Explanation:

Because it is true

What are the IUPAC name?

Answers

Answer:

IUPAC

Explanation:

International Union of Pure and Applied Chemistry

Claims · Evidence • Reasoning A student
claims that any change in matter can be
classified as either a physical change or a
chemical change. Do you agree or disagree?
What evidence would you use to support your
claim? Explain your reasoning.

Answers

As with the properties of a substance, the changes that substances undergo can be classified as either physical or chemical. During physical changes a substance changes its physical appearance, but not its composition. The evaporation of water is a physical change.

(I searched that up but here’s an explanation with my own words that you can use):

Change in matter can be classified as a physical change as well as a chemical change due to the properties of substance. A physical change changes substance within its appearance but not its composition. For an example: The evaporation of water is a physical change.

There you go hopefully that helped

Which statement describes the law of conservation of energy? A. All systems will exchange matter and energy with their surroundings. B. All systems can exchange energy, but not matter, with their surroundings. C. Energy cannot be created nor destroyed, but it changes from one form to another. D. Energy is destroyed in most chemical reactions when new products are formed.


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Answers

Answer:

C, energy cannot be created nor destroyed.

Explanation:

match the following
Of scinece chapter​

Answers

Anthrax - iv. Wool IndustryMushroom - v. SaprophyteTrade wind - i. Convection of heatChlorophyll - iii. PhotosynthesisMercury - ii. Thermometric fluid

o ponto po yung bawany to nagrade​

Answers

Answer:

????

Explanation:

Bdwibsxibqxibxqibciqbjxbqi

Name one common base that is NOT harmful to the body when ingested AND a product, or way, in which it is used.

Answers

Answer:

well when you eat some food you will get many tastes mixed with base and acid but salt from NA2CO3 can be a base if it is contained with weak acid.

Explanation:

Basically SALT can be one common base that is NOT harmful to the body when ingested AND a product, or way, in which it is used.

Magnesium hydroxide (Mg(OH)2) is not harmful to our body when ingested AND a product, or way, in which it is used. It is commonly used to get relief from acidity, that is caused when our stomach releases excessive acid. It neutrelises the acid and gives us relief. It is also called Milk of Magnesia commonly.

what is the definition of isomerism​

Answers

Answer:

Isomerism is the phenomenon in which more than one compounds have the same chemical formula but different chemical structures. Chemical compounds that have identical chemical formulae but differ in properties and the arrangement of atoms in the molecule are called isomers. Therefore, the compounds that exhibit isomerism are known as isomers.

The word “isomer” is derived from the Greek words “isos” and “meros”, which mean “equal parts”. This term was coined by the Swedish chemist Jacob Berzelius in the year 1830.

Explanation:

I
Gggggggggggggsgstststsysgtetwtwtst

Answers

Answer:

ummm u ok?

Explanation:

Help!!
There are 9.23 x 1023 molecules of water in a beaker, how many moles are there?

Answers

Answer: There are 1.53 moles present in [tex]9.23 \times 10^{23}[/tex]  molecules of water in a beaker.

Explanation:

According to the mole concept, there are [tex]6.022 \times 10^{23}[/tex] molecules present in 1 mole of a substance.

So, number of moles present in [tex]9.23 \times 10^{23}[/tex] molecules are calculated as follows.

[tex]Moles = \frac{9.23 \times 10^{23}}{6.022 \times 10^{23}}\\= 1.53 moles[/tex]

Thus, we can conclude that there are 1.53 moles present in [tex]9.23 \times 10^{23}[/tex]  molecules of water in a beaker.

can someone please help me im stuck​

Answers

Answer:

The answers to your questions are given below.

Explanation:

1. __H₂ + __O₂ —> __H₂O

The above equation can be balance as follow:

H₂ + O₂ —> H₂O

There are 2 atoms of O on the left side and 1 atom on the right side. It can be balance by writing 2 before H₂O as shown below:

H₂ + O₂ —> 2H₂O

There are 2 atoms of H on the left side and a total of 4 atoms on the right side. It can be balance by writing 2 before H₂ as shown below:

2H₂ + O₂ —> 2H₂O

Now the equation is balanced.

Elements >>> Reactants >>> Products

H >>>>>>>>> 4 >>>>>>>>>>> 4

O >>>>>>>>> 2 >>>>>>>>>>> 2

2. __ P₄ + __O₂ —> __P₂O₃

The above equation can be balance as follow:

P₄ + O₂ —> P₂O₃

There are 4 atoms of P on the left side and 2 atoms on the right side. It can be balance by writing 2 before P₂O₃ as shown below:

P₄ + O₂ —> 2P₂O₃

There are 2 atoms of O on the left side and a total of 6 atoms on the right side. It can be balance by writing 3 before O₂ as shown below:

P₄ + 3O₂ —> 2P₂O₃

Now, the equation is balanced

Elements >>> Reactants >>> Products

P >>>>>>>>> 4 >>>>>>>>>>> 4

O >>>>>>>>> 6 >>>>>>>>>>> 6

HEEELP! What are some examples of nuclear fusion? Select all the correct answers.

A: Being the power source of stars
B: Forming heavier elements from light elements
C: Generating electricity in power plants
D: Being used in thermonuclear weapons
E: Supplying the power source in nuclear submarines

Answers

Answer:

A B D

Explanation:

Answer:  A: Being the power source of stars

                B: Forming heavier elements from light elements

                D: Being used in thermonuclear weapons

Explanation: (Edmentum)

Describe the process of making 1.0 L of a 0.03 M solution of cobalt (II) chloride from the solid state. Be sure to include all instrumentation and glassware.

Answers

Answer:

By measuring out 3.9 grams of cobalt (II) chloride up to a volume of 1.0 L of solution.

Explanation:

Hello there!

In this case, considering this question about molarity, it turns out possible for us to calculate the required mass of cobalt (II) chloride by firstly compute the moles present in 1.0L of the given 0.03-M solution:

[tex]M=\frac{n}{V} \\n=V*M\\\\n=1.0L*0.03\frac{molCoCl_2}{L}\\\\n=0.03molCoCl_2[/tex]

Next, since the molar mass of cobalt (II) chloride is 129.84 g/mol, we compute the grams we need to measure out in order to prepare this solution:

[tex]m_{CoCl_2}=0.03molCoCl_2*\frac{129.84gCoCl_2}{1molCoCl_2} \\\\m_{CoCl_2}=3.9gCoCl_2[/tex]

Regards!

Give the Shorthand Electron Configuration for the following elements:

Nickel

Group of answer choices

[Kr] 3d8 4s2

[Ne] 3d6 4s2

[Ar] 3d8 4s2

Answers

answer of this question is [Ar]3d8 4s2

Answer: [Ar] 3d8 4s2

Explanation: Wikipedia

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