Why is one side of the moon called "the dark side of the moon"?

Answer:

Option C. 24 days / 4 grams

Explanation:

From the question given above, the following data were obtained:

Days Elapsed >>>> Mass Remaining

0 >>>>>>>>>>>>>>> 16

12 >>>>>>>>>>>>>>> 11

24 >>>>>>>>>>>>>>> 8

36 >>>>>>>>>>>>>>> 6

A. Determination of the half-life of Thorium-234.

To determine the half-life, it is important to know the definition of half life.

Half-life is defined as the time taken for a substance to reduce to half its original mass.

From the table given above, we can see that the original mass of the isotope is 16 g (i.e at 0 day). By day 24, the mass of the isotope is 8 g (i.e half the original mass). Thus, the half-life of the isotope is 24 days.

B. Determination of the mass of the isotope remaining after 2 half lives.

Original amount (N₀) = 16 g

Number of half-lives (n) = 2

Amount remaining (N) =?

N = 1/2ⁿ × N₀

N = 1/2² × 16

N = 1/4 × 16

N = 4 g

Thus, 4 g of the isotope is remaining after 2 half lives.

Summay:

Half-life = 24 days

Amount remaining after 2 half-lives = 4 g

Option C gives the correct answer to the question.

20.4 gallons of Isooctane fuel is 117.7786 lb.

1 gallon = 3785 cm3 = 4 quart; 1 pound = 453.6 g.

 So here. 20.4 gallons = 20.4 x 3785 cm³ = 77214 cm³ = 77214 ml

D = m/v  ⇒ mass = density x volume

Given density is 0.6919 g/cm3

Mass = 0.6919 x 77214 = 53424.3666 g

1 g = 1/453.6 lb ⇒ 53424.3666 g =53424.3666 /453.6 lb = 117.7786 lb.

isooctane or iso-octane is also known as 2,2,4-Trimethylpentane,  
being an important component of gasoline, it is  used in relatively large proportions (around 10%) to increase the knock resistance of fuel.
An antiknock agent is a gasoline additive which is  used to reduce engine knocking and also increases fuel's octane rating by raising the temperature and pressure at which auto-ignition occurs.

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Answer:

3.22 L

Explanation:

0.00 C = 273 K

k = C +273

606 K + 273 K = 879 K

879/273 = 3.219

V2 = 3.22 L

The molar mass is 3230.8 g/mol

First, we need to know that the formula for the general gas law  is represented as;

PV = nRT

such that the parameters are;

Substitute the values

1 × 2.33 = n × 8.314 × 433.15

Multiply the values, we get;

n = 2.33/ 8.314 × 433.15

Divide the values

n = 6.5 × 10⁻⁴ moles

But, number of moles = mass/molar mass

Molar mass = 2.10/ 6.5 × 10⁻⁴

Molar mass = 3230.8 g/mol

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Answer: A) A theory is the best possible explanation based on all existing evidence

A law in physics and chemistry is a description of what is going on. For instance, newton's law of motion helps us find out an objects acceleration if we know its mass and the force applied. The theory of gravity on the other hand is the best guess we make as to why objects with mass are attracted to one another.

Theories change over time if new evidence is found that contradicts the old theory. Saying "a theory is more important than a law" is subjective, and I would argue that both are equally important in their own way.

The atomic theory a theory is the best possible explanation based on all existing evidence. The correct option is A.

The word theory renowned as to an untested hunch or one can say a guess with not having a supporting evidence.

A theory, has nearly the opposite implications for scientists. A theory is a well-supported explanation of an innate phenomenon that can encompass laws, hypotheses, along with facts.

Theories are developed to elaborate, predict, as well as comprehend phenomena, also to challenge and extend existing understanding within the constraints of critical boundary assumptions.

A theory does not become a scientific law as new or better evidence accumulates.

The theories are explanations, as well as laws are patterns located in large amounts of data that are frequently expressed as an equation. A theory will always be a theory in all aspect, and a law will always be a law.

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Answer: Cells from the smallest to the largest of mammals often seem to be “one size fits all.” Now a closer look reveals that whether a cell lives in an elephant, mouse or something in between can make a big difference in its life

Explanation:

Explanation:

You have 112 g of Fe.

The atomic mass of Fe is 56 g/mol

112g Fe/ 56g/mol = 2 mol Fe  <---- you have to convert to moles of iron(iii) sulfate

From the balanced equation, you get that 2 moles of Fe react to produce 1 mole of Fe2(SO4)3

So, to convert:

2 mol Fe* (1 mol Fe2(SO4)3 / 2 mol Fe) = 1 mol Fe2(SO4)3

moles of Fe cancel and the answer is 1 mole of iron(iii) sulfate.

Substance that gives out ions when dissolved in water, which are able to conduct electricity describes an electrolyte.

Answer:

H

2

O

2

(aq)+ClO

4

−

(aq)⟶O

2

(g)+ClO

2

−

(aq)

All atoms except H and O are balanced.

The oxidation number of Cl changes from 7 to 3. The change in the oxidation number is 4.

The oxidation number of O changes from -1 to 0. The change in oxidation number per O atom is 1.

Total change in the oxidation number for 2 oxygen atoms is 2.

To balance the increase in oxidation number with decrease in the oxidation number, multiply H

2

O

2

and O

2

with coefficients 2.

2H

2

O

2

(aq)+ClO

4

−

(aq)⟶2O

2

(g)+ClO

2

−

(aq)

To balance O atoms, add 2 water molecules on RHS.

2H

2

O

2

(aq)+ClO

4

−

(aq)⟶2O

2

(g)+ClO

2

−

(aq)+2H

2

O(l)

The oxygen atoms are already balanced.

This is the balanced chemical equation

From the forgoing, we can conclude that the the correct statements are;

The redox reaction is one in which one specie is oxidized and the other is reduced. We can obtain the equilibrium constant from the relation;

E°cell = 0.0592/n log K

E°cell = cell potential

n = number of electrons

K = equilibrium constant

E°cell = -0.403 - 0.535 = -0.938 V

n = 2 electrons

Thus;

-0.938 =  0.0592/2 logK

-0.938 * 2/ 0.0592 = log K

K = 2 * 10^-31

Also;

ΔG = - nFE°cell

ΔG = - (2 * 96500 *  -0.938)

ΔG = 181kJ/mol

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Answer:

An acid is any hydrogen-containing substance that is capable of donating a proton (hydrogen ion) to another substance. A base is a molecule or ion able to accept a hydrogen ion from an acid.

Answer:

1.Sour in taste

2. Tum blue litmus into red

3. Acids change methyl orange to red

4.Phenolphthalein remains colourless

5. Acids do not give soapy touch

6. Give hydrogen ions in solution

Bitter in taste

Answer:

Because the sugar flour and eggs can no longer be separated. The properties of the materials have changed so it's a chemical change

Sugar, flour, and eggs cannot be separated. The materials' properties have changed, resulting in a chemical change.Therefore, crumbling a cookie is not a physical change.

Physical changes affect a chemical substance's form but not its chemical composition. Physical changes can be used to separate mixtures into their component compounds, but not to separate compounds into chemical elements or simpler compounds.

A chemical change is the transformation of one material into another, the formation of new materials with different properties, and the formation of one or more new substances. It occurs when one substance reacts with another to form a new substance.

A physical change is characterized by a change in physical properties. Melting, transition to a gas, change in strength, change in durability, changes in crystal form, textural change, shape, size, colour, volume, and density are all examples of physical properties.

Thus, crumbling a cookie is not a physical change.

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Answer:

A smaller temperature difference causes a smaller heat transfer

Explanation:

The greater the temperature difference, the greater the rate at which heat transfers.

Answer:

hydrocarbon

Explanation:

it reacts with oxygen to produce water and carbon dioxide.

hope this helps.

Answer:

3.5*1024

Explanation:

3584

The density of the solid block is 3.79 * 10⁻³ g/cm³.

The density of a substance is defined as the ratio of mass and volume of a substance.

Density measure how close together the particles of a given mass of a substance is. Substances with high density have greater masses compared to the volume of those substances whereas substances with low densities have greater volume compared to their masses.

The volume of the solid block = 78 * 55 * 35 = 150150 cm³

mass of solid block = 569 g

Density of the solid block = 569 g/150150 cm³

Density of the solid block = 3.79 * 10⁻³ g/cm³

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Sugar cube dissolve in hot water quickly

Sugar is a white crystalline sweet carbohydrate, a disaccharide, found in many plants and extracted from sugar cane

Here in this experiment add 60ml of cold water in plastic cup then add 60 ml of room temperature water to the another plastic cup and then add hot water in the in the another plastic cup then add sugar cube in this three cup and see in which cup the sugar cube dissolve fastly then in the hot water the sugar dissolve fastly because hot water has more energy than cold water and when water is heated the molecule gain energy and then move faster

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For a buffer that was prepared contain 0.50 M formic acid (HCOOH) and 0.50 M sodium formate (NaCOOH). the pH is mathematically given as

pH=3.95

Generally, the equation for the Hendersons equation   is mathematically given as

pH=pKa+log(SALT)/(ACID)

Where

moles of  (NaCOOH)=100*0.05/1000

moles of  (NaCOOH)=0.05moles

and  formic acid

moles of formic acid=100*0.05/1000

moles of  formic acid=0.05moles

Therefore

pKa=-logka

pKa=1.4*10*3.77

pH=3.77+log{0.06/0.04}

pH=3.95

In conclusion, the pH is

pH=3.95

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The mass of trifluoroacetic acid, C₂HF₃O₂ which contains 77.7 g of fluorine is 155.4 grams

We'll begin by obtaining the mass of C₂HF₃O₂ in one mole. Details below:

Thus, we can say:

57 grams of fluorine, F are present in 114 grams of C₂HF₃O₂

With the above information, we can obtain the mass of C₂HF₃O₂ that contains 77.7 g of fluorine. Details below:

57 grams of fluorine, F are present in 114 grams of C₂HF₃O₂

Therefore,

77.7 grams of fluorine, F will be present in = (77.7 grams × 114 grams) / 57 grams = 155.4 grams of C₂HF₃O₂

Thus, from the above calculation, we can conclude that the mass of trifluoroacetic acid, C₂HF₃O₂ is 155.4 grams

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Answer:

λ = 4.46 x 10⁻⁷ m = 446 nm

Explanation:

Applying Law of Conservation of Energy in this condition, we will get the following equation:

Total Energy of Combined Photons = Energy of 1st Photon + Energy of 2nd Photon

hc/λ = hc/λ₁ + hc/λ₂

hc/λ = hc(1/λ₁ + 1/λ₂)

1/λ = 1/λ₁ + 1/λ₂

where,

λ = wavelength of combined photon = ?

λ₁ = wavelength of 1st photon = 853 nm = 8.53 x 10⁻⁷ m

λ₂ = wavelength of 2nd photon = 935 nm = 9.35 x 10⁻⁷ m

Therefore,

1/λ = 1/(8.53 x 10⁻⁷ m) + (9.35 x 10⁻⁷ m)

1/λ = (0.1172 x 10⁷ m⁻¹) + (0.1069 x 10⁷ m)

1/λ = 0.2241 x 10⁷ m⁻¹

λ = 1/(0.2241 x 10⁷ m⁻¹)

λ = 4.46 x 10⁻⁷ m = 446 nm

Answer:

446

Explanation:

Matter are anything that is made up of atoms. The quantity of matter can be observed only on the basis of mass and volume calculation. Thus option C is correct option.

Matter is a substance that has some mass and can occupy some volume. The matter is mainly used in science. Matter can be solid, liquid or gas.

Matter is anything that is made up of atoms. Anything around us that can be physically seen and touched are matter. Ice, water and water vapors are example of matter.

Giant planet atmospheres have layers of clouds and aerosols (tiny liquid droplets) made from different chemicals because different chemicals condense at different temperatures.

Therefore,  option C is correct option.

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2. The pH is 4.22 × 10⁸. 3. pH is 7, 4. pOH is 9.7, 5. diprotic is explained below, 6. Amphoteric is explained below, 7. pH meter, 8. A buffer solution is explained below, 9. Titration is explained below, 10. Difference between strong and weak acids is explained below.

2. pH = -log[H⁺]

pH = -log(4.22 x 10⁻⁸)

pH ≈ 7.375

3. pH + pOH = 14

pH + 7 = 14

pH = 14 - 7

pH = 7

4. pH + pOH = 14

pOH = 14 - pH

pOH = 14 - 4.3

pOH ≈ 9.7

Now,

[H⁺] × [OH⁻] = 1.0 x 10⁻¹⁴

[OH⁻] = 1.0 x 10⁻¹⁴ / [H⁺]

[OH⁻] = 1.0 x 10¹⁴ / 10^(-pOH)

[OH⁻] = 1.0 x 10⁻¹⁴ / 10^(-9.7)

[OH⁻] ≈ 1.99 x 10⁻⁶ M

5. Being diprotic means that a molecule or ion can donate or release two protons (H⁺ ions) in an acid-base reaction.

6. Amphoteric refers to a substance that can act as both an acid and a base.

7. The pH can be measured using a pH meter or a pH indicator.

8. A buffer solution is a solution that can resist changes in pH when small amounts of acid or base are added to it.

9. Titration is a laboratory technique used to determine the concentration of a solution by reacting it with a solution of known concentration (titrant) of another substance.

10. A strong acid is an acid that completely ionizes in water, releasing all of its hydrogen ions. A weak acid is an acid that does not completely dissociate into ions when dissolved in water.

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Biotechnology is the use of living organisms or other biological systems in the manufacture of drugs or other products or for environmental management, as in waste recycling: includes the use of bioreactors in manufacturing, microorganisms to degrade oil slicks or organic waste, genetically engineered bacteria to produce human hormones, and monoclonal antibodies to identify antigens.

Biotech offers the possibility of improving human health, the environment, and agriculture while creating more sustainable modes of production.

Approximately 2.829 kilojoules (kJ) of energy is required to heat 0.24 kg of lutetium from 296.2 K to 373.5 K, assuming a specific heat of 0.154 J/g-K for lutetium.

What is Energy?

Energy is a fundamental concept in physics and refers to the ability of a system to do work. It is a scalar quantity and has various forms, such as kinetic energy, potential energy, thermal energy, electromagnetic energy, and nuclear energy.

To calculate the energy required to heat 0.24 kg of lutetium from 296.2 K to 373.5 K, we can use the formula:

Q = m * c * ΔT

where Q is the energy required, m is the mass of the lutetium, c is the specific heat of lutetium, and ΔT is the change in temperature.

First, we need to convert the mass of lutetium from kg to g:

m = 0.24 kg * 1000 g/kg = 240 g

Next, we can calculate the change in temperature:

ΔT = 373.5 K - 296.2 K = 77.3 K

Finally, we can use the formula to calculate the energy required:

Q = 240 g * 0.154 J/g-K * 77.3 K

Q = 2828.992 J or 2.829 kJ (to 3 significant figures)

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Water molecules pull the sodium and chloride ions apart, breaking the ionic bond that help them together.After the salt compounds are pulled apart ,the sodium and chloride atoms are surrounded by water molecules,as this diagram shows.Once this happens,the salt is desolved,resulting in a homogeneous solution

The ability to build molecules is made possible by a chemical bond, which is a strong attraction between atoms, ions, or molecules. The bond may be created by the sharing of electrons in covalent bonds or by the electrostatic interaction between ions that have opposing charges.

Chemical bonds keep the atoms in molecules together. Electrostatic forces between negatively charged electrons and positively charged atomic nuclei produce bonds (the positions of which in space are determined by quantum mechanics).

The three basic types of bonds are metallic, ionic, and covalent.

Definition: Valence electrons are moved from one atom to the next to finish the outer electron shell, creating an ionic bond. Example: NaCl is a typical ionically bonded substance (Salt)

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The partial pressure of hydrogen in the collected gas sample is 733.0 mm Hg (calculated by subtracting the partial pressure of water, 17.0 mm Hg, from the total atmospheric pressure, 750.0 mm Hg).

When a gas is collected over water, the presence of water vapor affects the total pressure observed. In this case, the total atmospheric pressure is given as 750.0 mm Hg, and the partial pressure of water vapor at 19.5°C is 17.0 mm Hg.

To determine the partial pressure of hydrogen, we need to subtract the partial pressure of water vapor from the total atmospheric pressure. Partial pressure refers to the pressure exerted by an individual gas component in a mixture. In this scenario, the collected gas is primarily hydrogen, with water vapor being the other component.

By subtracting the partial pressure of water vapor (17.0 mm Hg) from the total atmospheric pressure (750.0 mm Hg), we can find the partial pressure of hydrogen:

Partial pressure of hydrogen = Total atmospheric pressure - Partial pressure of water vapor

Partial pressure of hydrogen = 750.0 mm Hg - 17.0 mm Hg

Partial pressure of hydrogen = 733.0 mm Hg

Therefore, the partial pressure of hydrogen in the collected gas sample is 733.0 mm Hg.

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Explanation:

B) 3CuCl2+2AL..….2AlCl3+3Cu

hope it helps.

Balanced Equation:

3CuCl₂ + 2Al = 2AlCl₃ + 3Cu