What is the difference between melting and burning a substance? Is mass conserved in either process?

Answer:

Add a volume of a solution of known concentration is added to a volume of another solution in order to determine its concentration. Solutions in which a few drops of phenolphthalein have been added turn from colorless to brilliant pink as the solution turns from acidic to basic.

If you want the method:

Method

1) Use a pipette and pipette filler to add 25 cm3 of alkali solution to a clean conical flask.

2) Add a few drops of a suitable indicator and put the conical flask on a white tile.

3) Fill the burette with dilute acid. Flush the tap through to remove any air bubbles. Ensure the burette is vertical.

4) Slowly add the acid from the burette to the conical flask, swirling to mix. (The mixture may at first change colour, and then back again when swirled.)

5) Stop adding the acid when the end-point is reached (when the colour first permanently changes). Note the final volume reading.

6) Repeat steps 1 to 5 until three results are repeatable (in close agreement). Ideally these should lie within 0.10 cm3 of each other.

I hope it helps.

Answer:

To conduct a titration experiment, first fill the burette with an acid or base solution of known concentration. After that, take a burette reading from the top of the miniscus down to the bottom. Then, underneath the burette, place a flask containing an unknown concentration of acid or base. After that, fill the flask halfway with the appropriate indicator and shake it up. Add your titrate to the flask one drop at a time while stirring constantly. Continue to add the titrate until the color change is noticeable. Finally, take one more look at the burette to make sure everything is correct.

Explanation:

Hope it helps:)

Answer:

Transparent- air,water,sheet of plane glass,

Opaque- piece of rock,sheet of aluminium,mirror,wooden board,CD,umbrella,wall,sheet of carbon paper,sheet of cardboard

Translucent-sheet of polythene,sheet of cellophane,smoke,fog,wire

●Luminous- iron,lighted fluorescent tube,flame of gas burner, lighted torch,kerosene stove,sun,firefly

Non Luminous- water,air,rock,sheet of polythene,sheet of aluminium,mirror,wooden board,sheet of polythene,CD,smoke,sheet of plane glass,fog,wall,umbrela,sheet of carbon paper,cardboard sheet,cellophane sheet,wire,moon.

BRAINLIST PLS

I hope you feel better soon! :)

Answer:

4.530 X 10^23 MOLECULES OF CO2

Explanation:

Calculate the number of carbon dioxide (CO2) molecules produced in the

reaction if 0.7525 moles of oxygen gas (O2) are consumed

so

C + O2-----------CO2

1 MOLE OF 02 produces 1 mole of CO2

so

0.7525 moles O2 produce 0.7525 moles

1 mole is 6.02 X 10^23

so

0.7525 moles is 0.7525 X 6.02 X 10^23 -

=

4.530 X 10^23 MOLECULES OF CO2

Kinetic energy is energy that an object possesses due to its motion.

Lets look at each option:

A compressed spring has potential energy.

An arrow shot from a bow does have Kinetic energy.

Water in a reservoir at a hill top is potential energy.

A monkey hanging from a tree is potential energy.

This means that the answer is B) An arrow shot from a bow

I hope this helps! :)

According to law of conservation of energy,energy is converted from one form to another so by this fact an arrow shot from a bow has kinetic energy generated from potential energy.

According to law of conservation of energy, it is evident that energy is neither created nor destroyed rather it is restored at the end of a chemical reaction .

Law of conservation of mass and energy are related as mass and energy are directly proportional which is indicated by the equation E=mc².Concept of conservation of mass is widely used in field of chemistry, fluid dynamics.

Law needs to be modified in accordance with laws of quantum mechanics under the principle of mass and energy equivalence.This law was proposed by Julius Robert Mayer in the year 1842.

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Answer:

-O CH30

Explanation:

My Head Is About To Explode

Answer:

Percentage purity of a substance can be calculated by dividing the mass of the pure chemical by the total mass of the sample, and then multiplying this number by 100.

Explanation:

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Answer:

[tex]2al + 3h2so4 = > al2(so4)3 + 3h2 \\ eqvt \\ = > \frac{5.4}{27} = > \frac{5 \times 50}{1000} \\ .2 \: mol = > .25 \: mol \\ \\ so \: .25 \: is \: limiting \: reagent \\ according \: to \: ideal \: gas \: equation \\ pv = nrt \\ v = \frac{nrt}{p} \\ v = \frac{.25 \times .082 \times 300}{1} \\ = \frac{1}{4} \times 8.2 \times 3 \\ = 2.05 \times 3 \\ = 6.15litre \\ thank \: you[/tex]

Explanation:

You have a solution that contains 36 g HCl dissolved in 64 g water

Molar mass HCl = 36.45 g/mol

Mol HCl in 36 g = 36 g / 36.45 g/mol = 0.9876 mol

Molar mass H2O = 18 g/mol

Mol H2O in 64 g = 64 g / 18 g/mol = 3.5556 mol

Total mol = 0.9875 + 3.5556 = 4.5431 mol

Mol fraction HCl = 0.9876 mol / 4.5431 mol = 0.2174

Mol fraction H2O = 3.5556 / 4.5431 = 0.7826

The answer should have 2 significant digits:

Mol fraction HCl = 0.22

Mol fraction H2O = 0.78

Mol fraction has no units.

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Answer:

Brainlest

Explanation:

A polymer is a molecule made up of repeating units. These units, called “monomers”, form a long molecular chain. It might have branches, or it might just be one straight line of molecules, each connected in the same way. A monomer of polyethylene

Answer:

chemical reaction

Explanation:

The chemical reaction produces chemical changes to provide energy. Chemical reactions often involve changes in energy due to the breaking and formation of bonds.

Answer:

same question

Explanation:

Answer:

CH4 + O2 = CO2 + 2H2O

Explanation:

carbon dioxide and water is given off

The molecular formula of the compound is C12H15O3 hence the molar mass of the compound is 207 g/mol.

We need to obtain the number of moles of carbon, hydrogen and oxygen in the compound;

Carbon = 24.91 g/44g/mol × 1 mole of carbon = 0.566 moles

Mass of carbon =  0.566 moles × 12 g/mol = 6.792 g

Number of moles of hydrogen = 6.522 g/18 g/mol × 2 moles = 0.725 moles

Mass of hydrogen = 0.725 moles  × 1 g/mol = 0.725 g

Mass of oxygen = 10 - (6.792 g + 0.725 g) = 2.483 g

Number of moles of oxygen = 2.483 g/16 g/mol = 0.155 moles

Now we must divide through by the lowest number of moles;

C - 0.566/0.155   H - 0.725/0.155     O - 0.155/0.155

C - 4                    H - 5                        O - 1

The simplest formula is C4H5O Recall that the molar mass of the compound lies between 150.0 and 220.0 g/mol

4(12) + 5(1) + 16 = 69

Hence; n = 3 and the molecular formula of the compound is C12H15O3

The molar mass of the compound is; 12(12) + 15(1) + 3(16) = 207 g/mol

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Answer:

it should be the second one since London dispersion causes interaction between molecules.

hope I helped.

Generally non ionic species with no polarity forms the London -dispersion bonds. London dispersion is weaker than the dipole-dipole interaction and hence it have less boiling  point.

Boiling point of  a substance is the temperature at which the substance changes from liquid state to gaseous state or vapor where, the two states are in equilibrium.

Boiling of a substance depends on the molecular weight, bond type,temperature, pressure as well as purity of the substance.

London dispersion force is formed between two non-polar atoms. These atoms when come closer they attains a temporary polar nature and gets bonded.

Dipole-dipole bond is formed between two atoms of permanent dipole moment and they are polar compounds. Thus dipole-dipole interaction is stronger than London dispersion interaction. A strong bond needs more energy to boil.

Hence, molecules with  Dipole-Dipole bond is having higher boiling point.

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Answer:

ok

Explanation:

Answer:

heat energy released by the substance

The energy change that takes place during deposition is that heat energy is released by the substance. This statement is true about deposition.

Deposition is a phase transition that occurs when a gas is converted directly to a solid without passing through the liquid state. During deposition, energy is released by the gas particles and absorbed by the surface, resulting in a decrease in the energy of the gas particles and an increase in the energy of the surface particles.As a result, the substance releases heat energy as it changes from a gas state to a solid state.

Therefore, the correct option is:Heat energy released by the substance.

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The anti periplanar geometry for the E2 reaction of (CH3)2CHCH2Br with base is shown in the image attached as well as the structure of the product formed in the reaction.

In organic chemistry, an antiperiplanar conformation is one in which the groups point up and down at a dihedral angle of 180° away from one another. In the image attached, the antiperiplanar conformation of (CH3)2CHCH2Br is shown.

Recall that an E2 reaction is a synchronous elimination reaction where to atoms leave at the same time. The product of this reaction is also shown in the image attached.

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Answer:

Answer:

Aluminium atoms =  4.13 *10^22 aluminium atoms

Explanation:

Explanation:

Step 1: Data given

Mass of Al2O3 = 3.50 grams

Molar mass of Al2O3 = 101.96 g/mol

Number of Avogadro = 6.022 * 10^23 /mol

Step 2: Calculate moles Al2O3

Moles Al2O3 = mass Al2O3 / molar mass Al2O3

Moles Al2O3 = 3.50 grams / 101.96 g/mol

Moles Al2O3 = 0.0343 moles

Step 3: Calculate moles Aluminium

In 1 mol Al2O3 we have 2 moles Al

in 0.0343 moles Al2O3 we have 2*0.0343 = 0.0686 moles Al

Step 4: Calculate aluminium atoms

Aluminium atoms =  moles aluminium * Number of Avogadro

Aluminium atoms =  0.0686 * 6.022 * 10^23

Aluminium atoms =  4.13 *10^22 aluminium atoms

Answer:

Words are filled in

Eating a healthy breakfast gives your body the energy needed to help you start your day.. The girl in the photo is having cereal and orange jucie, both of which have stored chemical energy, a form of potential energy. The girls body breaks down the components of the food to access the energy in them. Later in the day, some of this energy is transformed into kinetic energy that will allow the girl to study and play sports. Some of this energy is also transformed into thermal energy that keeps her body warm.

Explanation:

The volume of the gas is 27 ml

The calculation can be done as follows

The first step is to convert the pressure to atm

convert 2280 tors to atm

760 tors= 1 atm

= 2280/780

= 3 atm

The formula is

PV= nRT

The next step is to write out the parameters

Pressure= 3 atm

Temperature= 21 °C

no of moles= 32.1 mole

volume= ?

(r)constant= 8.314

3 × v= 32.1×8.314×21

3v= 81.080

V= 81.080/3

V= 27 ml

Hence the volume of the gas is 27 ml

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Answer:

yes

Explanation:

what would happen if the next time you needed tape or glue you remember, oh wait theres none at the house, thats just an example of why you would indeed need adhesives

Answer:

E = 6.27 × 10⁻²³ Joules

Explanation:

E = h (Plancks constant) × f (frequency)

(Plancks constant = 6.63 × 10⁻³⁴ J×s)

f = λ × c (used to find frequency so you can satisfy energy equation)

*Have to find wavelength in meters to multiply by speed of light*

1. f = (3.15 × 10⁻⁷ m) × (3 × 10⁸ m/s)

2. f = 9.45 × 10¹⁰ s

3. E = (6.63 × 10⁻³⁴ J×s [Plancks constant]) × (9.45 × 10¹⁰ s)

E = 6.27 × 10⁻²³ Joules

Answer:

1. The core electrons are 10

2. The valence electrons are 8

Explaination:

Core electrons are electrons located in  the inner shells of and atom.

Valence electrons are electrons located on the outermost shell of an atom

From the question given above, we obtained:

Ar (18) => [Ne] 3s²3p⁶

Recall

Ne (10) => 1s² 2s²2p⁶

Therefore,

Ar (18) => [1s² 2s²2p⁶] 3s²3p⁶

From the above illustration,

Inner shell (core shell) => 1s² 2s²2p⁶

Outermost shell (valence shell) => 3s²3p⁶

1. Determination of the core electrons

Inner shell (core shell) => 1s² 2s²2p⁶

Core electrons = 2 + 2 + 6

Core electrons = 10

2. Determination of the valence electrons

Outermost shell (valence shell) => 3s²3p⁶

Valence electron = 2 + 6

Valence electron = 8

Answer:

10 core electrons

8 valence electrons

Explanation:

Answer:

5.627 × 1019 milliliters

Explanation:

is this what you wanted?

Answer:

C. 176 grams

Explanation:

48g / (12g/mol) = 4.0mol. Moles of Oxygen used. = 128g / (32g/mol) = 4.0mol. C + O2 => CO2. Therefore ...

Answer:

Option B

Explanation:

Magnesium is an alkali earth metal and chlorine is a nonmetal. Due to this, and their differences in electronegativity, the elements form an ionic bond. Since magnesium has two valence electrons, it will give them up to two chlorine atoms (which has 7 valence electrons), which needs them to complete its octet. From this, magnesium forms a cation, and will have the ion formula Mg(2+). The two chlorine atoms form anions, and will have the ion formula Cl(1-).

Terms:

——Industrial waste——— should be treated chemically before deposing it to rivers. ​

=》The waste from factories & industries are highly acidic/base. This leads to the increase/decrease of the pH value of water in the rivers making it contaminated & unfit for drinking. This also causes a huge problem for aquatic organisms.

=》Industrial waste should be neutralized before depositing it into water bodies to reduce these risks.

_______

⚜ Hope it helps :))

Answer: Industrial waste

Explanation:

The thermal energy of a material increases with temperature. Therefore, the radiator  has the higher thermal energy.

When the temperature rises, a type of energy called thermal energy is produced. The amount of thermal energy usually directly inversely proportional to the object's change in temperature. Thermal energy takes the form of heat.

The thermal energy of a material increases with temperature. The quicker motions of the substance's atoms and molecules are what cause thermal energy to grow as temperature rises.

In some cases, a substance's molecules will separate from one another and leave because the temperature is just so high. Unexpectedly, thermal energy also affects the states of matter. The radiator  has the higher thermal energy.

Therefore, the radiator has the higher thermal energy.

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Answer:

[tex]\boxed {\boxed {\sf 1.6 \times 10^{24} \ atoms \ Si}}[/tex]

Explanation:

We are asked to find how many atoms are in a sample of 75 grams of silicon.

First, we must convert grams to moles using the molar mass. This is the mass of 1 mole of a substance. The molar mass is found on the Periodic Table because it is equal to the atomic mass, but the units are grams per mole instead of atomic mass units.

Look up the molar mass of silicon.

We convert using dimensional analysis, so we must set up a conversion factor.

[tex]\frac {28.085 \ g \ Si}{1 \ mol \ Si}[/tex]

We are converting 75 grams of silicon to moles, so we multiply by this value.

[tex]75 \ g \ Si*\frac {28.085 \ g \ Si}{1 \ mol \ Si}[/tex]

Flip the conversion factor so the units of grams of silicon cancel.

[tex]75 \ g \ Si*\frac {1 \ mol \ Si}{28.085 \ g \ Si}[/tex]

[tex]75 *\frac {1 \ mol \ Si}{28.085 }[/tex]

[tex]\frac {75}{28.085} \ mol \ Si[/tex]

[tex]2.670464661 \ mol \ Si[/tex]

Next, we convert moles to atoms using Avogadro's Number, or 6.022 ×10²³. This is the number of particles (atoms, molecules, formula units, etc.) in 1 mole of a substance. In this problem, the particles are atoms of silicon.

Set up another conversion factor, this time with Avogadro's Number.

[tex]\frac {6.022 \times 10^{23} \ atoms \ Si}{1 \ mol \ Si}[/tex]

Multiply by the number of moles we found.

[tex]2.670464661 \ mol \ Si*\frac {6.022 \times 10^{23} \ atoms \ Si}{1 \ mol \ Si}[/tex]

The units of moles of silicon cancel.

[tex]2.670464661 *\frac {6.022 \times 10^{23} \ atoms \ Si}{1 }[/tex]

[tex]2.670464661 * {6.022 \times 10^{23} \ atoms \ Si}[/tex]

[tex]1.60815382 \times 10^{24} \ atoms \ Si[/tex]

The original value of grams (75) has 2 significant figures, so our answer must have the same. For the number we found, that is the tenths place. The 0 in the hundredths place tells us to leave the 6 in the tenths place.

[tex]1.6 \times 10^{24} \ atoms \ Si[/tex]