A 345. g sample of an unknown substance was heated from 45.0°C to 167.7°C. In the process, the substance absorbed
18.942 kJ of energy. What is the specific heat of the substance? Give your answer in both standard and scientific notation.
Was this an endothermic or exothermic process? Identify the substance based on the table below.

The color of the solution after reaching a pH of 8 is pink.

In the process of titration of acetic acid with aqueous NaOH, phenolphthalein is used as an indicator. Phenolphthalein is nearly colorless in acidic solutions, but it turns the solution into pink at a pH of 8.

As you titrate vinegar, we can observe that the pink color is more persistent as we add more base. When a faint pink color persists for at least 30 seconds, we can understand that the endpoint has been reached.

The pH scale ranges between 0 - 14, if the pH is below 7 it indicates acidic, if it is exactly 7 then it indicates neutral and if it is greater than 7 it indicates a base.

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Explanation:

time ➟ second

temperature ➟ Kelvin

ampere ➟ electric current

luminous intensity ➟ candela

mole ➟ amount of a substance

liter ➟ volume

length ➟ meter

Answer:

Explanation:

Kilogramm → mass

Ampere → electric current

Mole → amount of a substance

Liter → volume

Answer:

1.11 x 10⁻¹⁹ J

Explanation:

To calculate the energy of the light, you need to use one of Einstein's equations:

E = hf

In this equation,

-----> E = energy (J)

-----> h = Planck's Constant (6.626 x 10⁻³⁴ J·s)

-----> f = frequency (Hz)

You can plug the constant and given value into the equation and solve for "E". The final answer should have 3 sig figs like the given value.

E = hf                                                                   <----- Einstein's equation

E = (6.626 x 10⁻³⁴ J·s)(1.68 x 10¹⁴ Hz)                 <----- Insert values

E = 1.11 x 10⁻¹⁹ J                                                  <----- Multiply

The electron configuration of O₂ is 1s² 2s² 2p⁴.

Electron configuration can simply be defined as the arrangements of electrons of atoms of elements in the orbitals or electrons shells. In order words, it simply means putting the electrons in order from the smallest orbital or shell to the biggest one.

That being said, from the task given above, the atomic number of oxygen is 8, meaning that if we are put down, the electron configuration of oxygen, we will have to distribute 8 electrons around its orbitals. An atom simply means the smallest particle of an element which can take part in a chemical reaction. An element is a substance which cannot be splitted into simpler forms by ordinary means.

So therefore, we can now confirm and deduce from the explanation above that electron configuration of the oxygen atom or element is the distribution of electrons around its orbitals.

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Answer:

below

Explanation:

From periodic table this is dysprosium

The number of moles of O₂ required to react with 3.6 moles of C₂H₄O₃ is 5.4 moles

First, let us observed the balanced equation, to what we can obtain. This is shown below

2C₂H₄O₃ + 3O₂ -> 4CO₂ + 4H₂O

From the balanced equation above,

2 moles of C₂H₄O₃ reacted with 3 moles of O₂

With the above information from the balanced equation, we can determine the number of moles of O₂ required to react with 3.6 moles of C₂H₄O₃. This can be obtained as follow:

From the balanced equation above,

2 moles of C₂H₄O₃ reacted with 3 moles of O₂

Therefore,

3.6 moles of C₂H₄O₃ will react with = (3.6 × 3) / 2 = 5.4 moles of O₂

Thus, number of mole of O₂ required is 5.4 moles

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The theoretical mass of NaCl would result from reacting 3.0 moles of NaHCO3 with excess HCI is 175.32 g.

This problem is solved by using the concept of moles:

Mole is a term which is defined as a ratio of theoretical mass of compound to the molar mass of compound.

Mathematically,

Moles = given mass/molar mass

Molar mass of NaCl = 58.44 g/Mol

Now we have to calculate the moles of NaCl

[tex]NaHCO_{3} + HCl = > NaCl + H_{2}O + CO_{2}[/tex]

From the chemical equation, we noticed that moles of NaHCO3 is equal to moles of NaCl.

Since moles of NaHCO3 = 3

Therefore, moles of NaCl = 3

Now, by substituting all the values, we get

Theoretical mass of NaCl = 3 x 58.44 = 175.32 g

Thus we concluded that the theoretical mass of NaCl would result from reacting 3.0 moles of NaHCO3 with excess HCI is 175.32 g

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The ratio of the carbon to other atoms would be 2.49375:3.9901:1.000 and the empirical formula of the compound would be  [tex]C_2H_8O[/tex]

The compound contains C, H, and O according to the following information:

C = 4.9875 mol

H = 7.9802 mol

O = 2.00 mol

In order to obtain the empirical formula of the compound, divide the mol of each atom by the smallest mol. In this case, the smallest mol is 2.00

C = 4.9875/2.00

  = 2.49375

H = 7.9802/2.00

    = 3.9901

O = 2.00/2.00

   = 1.0000

Thus, the ratio of carbon to the rest of the atoms present in the compound is 2.49375:3.9901:1.000

In order to find the empirical formula of the compound, the mole of each atom needs to be approximated to the nearest whole number.

C = 2

H = 8

O = 1

Thus, the empirical formula of the compound is [tex]C_2H_8O[/tex].

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In Period 3 and Group 16, Sulfur is present and has the element symbol is ''S''.

Sulfur is a chemical element having the symbol S and its atomic number 16 and belongs to group 16. It is abundant around the world and nonmetallic under normal conditions. Sulfur element is used in the vulcanization of black rubber such as a fungicide and black gunpowder. Most element of sulfur is used in the production of acid known as sulfuric acid, which is the most important chemical produced by civilizations of the west.

Element of sulfur is lowly toxic to people but ingesting too much sulfur may cause a burning effect or diarrhea. Breathing in sulfur dust can damage the airways or cause coughing. It can irritate to the skin and eyes of a person.

So we can conclude that Sulfur is the element that is located in Period 3 and Group 16.

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Answer:

3

Explanation:

at first try balancing the carbon first. At first multiply 2 with CO2, that produces 2 carbon and 8 oxygen. On reactant side we have 3 Oxygen. Now look at Hydrogen. There are 6 hydrogen atoms on the reactant side. So you need to multiply 3 with H20 to be 6 hydrogen atoms as 3*2 = 6.

Final reaction: C2H5OH + 3O2 ------> 2CO2 + 3H2O

This isn't chemistry but I believe the answer is D, before a suspect in custody is questioned.

Hope this helped.

Answer: D

Explanation:

The nuclear equation for the Alpha decay of a radioactive Radium-226 isotope is ²²⁶₈₈Ra → ²²²₈₆Rn + ⁴₂He

The sun of the mass numbers of the reactant equal the sum of the mass numbers of the product and radium 226 decay by alpha particles radiation to an inert gas and radon 222 which also decay by alpha particle radiation and due to the short half life of radon 222 there is high probability it will decay in the body and alpha particle is a helium nucleus it contain 2 proton an 2 neutron foe mass number of 4 and during alpha decay an atomic nucleus emit an alpha particles and it transform into an atom with atomic number 2 less and mass number 4 less

And the radium 226 decay through alpha particles emission to form radon 222 according to the equation ²²⁶₈₈Ra → ²²²₈₆Rn + ⁴₂He

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Thus, radium-226 decays through α-particle emission to form radon-222 according to the equation:

The terms "energy state" "electrons" and "light" colors of a flame test are produced is because excitement of electron caused by the increased temprature

The color observed during the flame test result from the excitement of the electron caused by the increased temprature and the electron jumps from their ground state to a higher energy level and as they return to their ground state they emit visible light and the flame test is an analytical procedure used in chemistry to detect the presence of certain element and primarily metal ion and based on each element characteristics emission spectrum the color of flames in general also depend on temprature and oxygen and it sees the different color in the flame

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If the temperature of the sample of gas changes from 25°C to 45°C, the volume of the gas will increase.

Charles's law is the gas law stating that the density of an ideal gas is inversely proportional to its temperature at constant pressure.

In other words, the law states the volume of a gas is directly proportional to the temperature of the gas. The equation is given as follows:

V₁/T₁ = V₂/T₂

Where;

According to this question, a sample of a gas at constant pressure increases in temperature from 25°C to 45°C. This means that as the temperature increases, the volume also increases.

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The radioactive sample that would contain the greatest remaining mass of the radioactive isotope over 10 years is 4.0 grams of Co-60 because it has the longest half-life.

The half-life of an isotope of an element is directly related to the number of particles remaining over a given period of time. The longer the half-life of an isotope of an element, the greater the number of particles of that element that remain over a given period of time.

The half-life of the given atoms os given below:

Half-life of Au-198 is 2,607 days

Half-life of K-42 is 12.32 hours

Half-life of P-32 is 14.3 days

Half-life of Co-60 is 5.3 years.

Hence, Co-60 has the longest half-life.

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Answer:

Put a coefficient of 2 in front of P4. Then a coefficient of 6 in front of O2. Then a coefficient of 4 in front of P2O3.

Explanation:

This is a synthesis reaction because of the two different atoms form a compound

Answer:

True. When chemists experiment with clinical drugs, they may inadvertently create new side effects that were not present in the original drug. Additionally, the new drug may interact with other drugs in unexpected ways, which can also create new side effects.

Answer:Electrons that are closer to the nucleus are in filled orbitals and are called core electrons. Valence electrons are farthest from the positive charge

Explanation:

[tex]{ \boxed{ \blue{ \sf{properties \: of \: fullerence}}}}[/tex]

• Man made allotrope of carbon obtained from graphite which when treated with [tex]CS_{2}[/tex]

• sp² hybridised.

• Dark shining and conducts electricity.

• It has 20 hexagonal and 12 pentagonal.

The option that best represent the depiction of the Closeup of a glass windshield is option A: trace evidence

In paper bindles, coin envelopes, pill boxes, or film cans that can be tagged and completely sealed, place the little glass pieces before placing them in the last. Put big glass pieces in boxes. Use cotton or tissue to cushion individual pieces while shipping to avoid breakage and damaged edges.

Note that the field of forensic science known as "trace evidence analysis" focuses on the minute transfers of materials that are invisible to the unassisted eye.

Hence, Trace evidence must be handled carefully and analyzed using specialist methods.

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The Law of conservation of mass states that  option C: matter is neither created nor destroyed.

Physical and chemical changes can cause matter to transform into different forms, but no matter what happens, matter is always conserved. There is no creation or destruction of matter; the amount of matter is the same before and after the transformation.

The principle of matter conservation. argues that matter cannot be generated or destroyed during a chemical reaction. The same number of atoms exist before and after the alterations even though the matter may shift from one form to another. reactant.

Therefore, According to the principle of mass conservation, neither chemical processes nor physical changes can create or destroy mass in an isolated system. The mass of the products and reactants of a chemical reaction must be equal, in accordance with the law of conservation of mass.

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See full question below

1. Multiple-choice

Q.

Conservation of matter article questions

Law of conservation of mass states that

answer choices

matter is created

matter is destroyed

matter is neither created nor destroyed

matter does not change

Answer:

Surface tension due to cohesion

Explanation:

Water molecules are polar meaning they have dipoles. The hydrogen end is partially positive while the oxygen end is partially negative. This is because oxygen with high atomic mass attracting most of the molecule's electron cloud to its end.

Due to this phenomenon water molecules act like little magnets that attract each other. The attraction of the molecules forms hydrogen bonds with each other. This is called cohesion (attraction of similar molecules).  Due to this, water is able to create a surface tension that acts like a ‘skin’ and can support some weight (including its own weight) without collapsing.

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Answer:

Cohesion of water

Explanation:

cohesion means sticking together so Before it overflows, the water forms a dome-like shape(rounded) above the rim of the glass. This dome-like shape forms due to the water molecules' cohesive properties, or their tendency to stick to one another.

Answer:

1.25*10^24 atoms with sig figs

Explanation:

To find the number of atoms, an easy way to do this would be to convert the mass to the number of moles, then convert moles to the number of atoms.
There are 40.08 grams of calcium per mole, so 83.4 grams of calcium would have 83.4/40.08 moles of calcium, or about 2.081 moles of calcium
Each mole of something contains about 6.022*10^23 of that something, so 2.081 moles of calcium atoms would equal 2.081 *(6.022*10^23) atoms. 2.081 *(6.022*10^23) equals 1.25*10^24, so there would be 1.25 * 10^24 atoms in 83.4 grams of calcium

The product of this reaction using inorganic by-products using H2/Lindlar's catalyst is cis-2-butene.

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The mass of water is consumed by the reaction of 8.86 g of carbon dioxide is 3.62 g.

The balanced chemical equation for photosynthesis is given by:

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

Therefore, from the above reaction it is clear that 6 moles of carbon dioxide and 6 moles of water combines to produce 1 mole of glucose sugar and 6 moles of oxygen.

The molar mass of carbon dioxide is 44.01 g/mol.

Therefore, the number of moles of carbon dioxide in 8.86 g of CO₂ is :

Number of moles of CO₂ = (8.86 g) ÷ (44.01 g/mol )

                                          =0.201 moles

From the balanced chemical equation 6 moles of water is consumed with CO₂.

Number of moles of water = 6moles H₂O ÷ 6moles CO₂ × 0.201mol CO₂

                                             = 0.201 mol

The molar mass of water is 18.01 g/mol.

Therefore the mass of water consumed is :

Mass of water = Number of moles of water × Molar mass of water

                        = 0.201 mol × 18.01 g/mol

                        = 3.62 g

Hence, the mass of water is consumed by the reaction of 8.86 g of carbon dioxide is 3.62 g.

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The volume (in milliliters) occupied by a 0.327 g sample of CO₂ gas at 22.5 °C and 755 Torr is 0.115 L.

The ideal gas equation is given as :

P V = n RT

where,

P = pressure = 755 torr = 0.99 atm

V = volume

n = moles

R = gas constant = 0.0821 atm L / mol K

T = temperature = 273 + 22.5 = 295.5 K

mass of CO₂  = 0.327 g

molar mass of CO₂  = 44 g

number of moles of CO₂  = mass / molar mass

                                          = 0.327 / 44

                                          = 0.0047 mol

P V = n R T

V = (n RT) / P

V = ( 0.0047 × 0.0821 × 295.5 ) / 0.99

V = 0.115 L

Thus, The volume (in milliliters) occupied by a 0.327 g sample of CO₂ gas at 22.5 °C and 755 Torr is 0.115 L.

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The quantity of heat energy evolved in the reaction, given that 0.25 mole of KCl is mixed with 0.25 mole of NaOH in a calorimeter is 2830.5 calories

To obtain the heat energy evolved, we shall begin by obtaining change in the temperature of the water. This is obtained as follow:

ΔT = T₂ - T₁

ΔT = 35.5 - 27

ΔT = 8.5 °C

Finally, we shall determine the quantity of heat energy evolved in the reaction. Details below

Q = MCΔT

Q = 3.33×10² × 1 × 8.5

Q = 2830.5 calories

Thus, the quantity of heat energy evolved is 2830.5 calories

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Taking into account the definition of density, the length of each side of the cube is 4 cm.

In other words, density is a quantity that allows to measure the amount of mass in a certain volume of a substance.

The expression for the calculation of density is:

density= mass÷ volume

From this expression it can be deduced that density is inversely proportional to volume: the smaller the volume occupied by a given mass, the higher the density.

In this case, you know that:

Replacing in the definition of density:

2 g/cm³= 128 g÷ volume

Solving:

2 g/cm³× volume= 128 g

volume= 128 g÷ 2 g/cm³

volume= 64 cm³

The volume of a cube is equal to the measure of its side to the cube. That is to say:

Volume = side x side x side = side³

So, the length of each side of the cube can be calculated as:

64 cm³= side³

∛64 cm³= side

4 cm= side

In summary, each side of the cube has a measure of 4 cm.

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Taking into account the definition of Ideal Gas Law, the volume of the container, the pressure of the gas, the number of gas particles, and the temperature of the gas are related by the Ideal Gas Law.

An ideal gas is a theoretical gas that is considered to be composed of randomly moving point particles that do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.

An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law:

P×V = n×R×T

where:

In summary, the volume, the pressure, the number of gas particles, and the temperature are related by the Ideal Gas Law.

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