Beryllium, the first element in group 2, has an atomic number of 4. The second element in this group has an atomic number of.

The minimum mass of octane that could be left over is 0.468 grams.

Step 1: Data given

Mass of octane = 3.4 grams

Mass of oxygen = 20.5 grams

Molar mass octane = 114.23 g/mol

Molar mass oxygen = 32.0 g/mol

Step 2: The balanced equation

2C₈H₁₈ + 25O₂ → 16CO₂ + 18H₂O

Step 3: Calculate the number of moles

Moles = mass / molar mass

Moles octane = 3.4 grams / 114.23 g/mol

Moles octane = 0.0297 moles

Moles O₂ = 20.5 grams / 32.0 g/mol

Moles O₂ = 0.640 moles

Step 4: Calculate the limiting reactant

For 2 moles octane we need 25 moles O₂ to produce 16 moles CO₂ and 18 moles H₂O

O₂ is the limiting reactant. It will completely be consumed (0.640 moles). There will react 0.0320/ 12.5 = 0.0256 moles.

There will remain 0.0297 - 0.0256  = 0.0041 moles octane.

Step 5: Calculate mass octane remaining

Mass octane = moles * molar mass

Mass octane = 0.0041 moles * 114.23 g/mol

Mass octane = 0.468 grams

The minimum mass of octane that could be left over is 0.468 grams.

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Radium have a lower ionization energy than Barium because electrons are closer to the nucleus

What is ionization energy?

Ionization energy can be simply stated as a measurement of an atom's or ion's inclination to give up an electron or of how challenging it is to remove an electron from them. An electron is often lost when a chemical species is in its ground state.

The atom displays a smaller radius than anticipated and the s electrons are more challenging to expel because these electrons are located nearer the nucleus. The first ionization enthalpy of Radium is higher than that of Barium.

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A physical model of a crime scene is called  an animation

The evidence that crime scene investigators gather includes fingerprints, tyre tracks, hairs, fibres, blood, and other bodily fluids. The NIJ sponsors initiatives to enhance: Blood and other bodily fluids at the location were identified.

There are three different sorts of imprint evidence: bite marks, tool marks, and shoe and tyre prints. Each of these may employ one or more of the following collection strategies, such as taking photos, lifting objects with tape, or plaster-casting.

Physical evidence, also known as actual evidence or material evidence, is any tangible thing that is presented as evidence in a court case that has some connection to the issue that gave birth to the dispute.

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Answer:

The answer is O a reconstruction.

Explanation:

Got it right on the test.

not gon find it here cuh

Explanation:

The concentration of the acetic acid solution is approximately 0.0128 mol/L, given the information provided.

To determine the concentration of the acetic acid solution, we need to use the given enthalpy change and the heat evolved in the reaction.

The enthalpy change (ΔH) is given as 55.7 kJ/mol, which represents the heat released or absorbed per mole of acetic acid involved in the reaction.

The heat evolved in the reaction is given as 716.12 J. However, we need to convert it to kilojoules to match the unit of the enthalpy change. There are 1000 J in 1 kJ, so 716.12 J is equal to 0.71612 kJ.

Now, we can set up a proportion to find the concentration of the acetic acid solution. The heat evolved is directly proportional to the moles of acetic acid involved in the reaction, which is in turn proportional to the concentration of the solution.

Let's assume the concentration of the acetic acid solution is c mol/L.

The proportion can be set up as:

ΔH (kJ/mol) / Heat evolved (kJ) = 1 mol / c L

Substituting the values we have:

55.7 kJ/mol / 0.71612 kJ = 1 mol / c L

Simplifying:

c = 1 mol / (55.7 kJ/0.71612 kJ)

c ≈ 0.0128 mol/L

Therefore, the concentration of the acetic acid solution is approximately 0.0128 mol/L, given the information provided.

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Type of force would put the soccer ball in motion is unbalanced force.

Unbalanced force is  defined as when the net force acting on the object is not equal to zero. The unbalanced force brings an object in motion. while balanced force acting on any object does not change the state of rest or uniform motion. The soccer ball moves from one place to another because unbalanced forces are acting on the soccer ball. this means the resultant force acting on soccer ball is not equal to zero.

Thus, Type of force would put the soccer ball in motion is unbalanced force.

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Answer:

b) Unbalanced force

Explanation:

Unbalanced force is the type of force which puts the soccer ball in motion while kicking it. Hence, option (b) is the correct answer.

The two elements that do not have a second energy levels are Hydrogen (H) and Helium (He)

Energy levels are nothing but the 3-D spaces around the nucleus of an atom. The electrons revolve around the nucleus in their respective energy levels. Each energy levels can accommodate only a particular number of electrons.

For example, first energy level can accommodate only a maximum of 2 electrons whereas second energy level can accommodate 8 electrons.

Hydrogen has 1 electron and helium has 2 electrons around their respective nucleus. In both hydrogen and helium, electrons are accommodated in the first energy level.

Hence, the two elements that do not have a second energy levels are Hydrogen (H) and Helium (He)

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The percent yield is 83.29%.

The real yield is calculated as the theoretical yield divided by the theoretical yield multiplied by 100. % Yield = (Actual Yield % Theoretical Yield × 100%) Many factors can cause a chemical reaction's actual yield to be lower than its theoretical yield.

Numbers of moles copper = 0.0970 moles

Mass of copper(I) sulfide = 6.43 grams.

Balanced equation

2Cu + S ⇒ Cu₂S

Calculate moles of Cu₂S

To create 1 mol of Cu2S from 2 moles of Cu, we require 1 mole of S.

For 0.0970 moles Cu we'll have 0.0970 / 2 = 0.0485 moles

Calculate mass of Cu₂S

Mass Cu₂S = moles Cu₂S × molar mass Cu₂S

Mass Cu₂S = 0.0485 moles × 159.16 g/mol

Mass Cu₂S = 7.72 grams

Calculate percent yield

Percent yield = (actual yield/ theoretical mass) × 100%

Percent yield = (6.43grams / 7.72 grams) × 100%

Percent yield = 83.29 %

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Two solutions are made by mixing sugar and enough water to make a 1 liter solution. 10% sugar has more solvent.

In chemistry, a solution is a homogeneous mixture of two or more compounds in their relative proportions that can be continually altered up to what is referred to as the limit of solubility. Although the word "solution" is frequently used to refer to the liquid state of matter, solutions of gases and solids are also possible. A solute is dissolved by a solvent (s), which is a substance (from the Latin solv, "loosen, untie, solve,") to produce a solution. The most common form of a solvent is a liquid, although other forms include solids, gases, and supercritical fluids. Depending on the temperature, a different amount of solute can dissolve in a given volume of solvent. Solvents are extensively utilized in paints, paint removers, inks, and dry cleaning.

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answer

1. Neon

2. Astatine

3. oxygen

4. Arsenic

5. Silicone

6. Aluminium

7. Calcium

8. Sodium

Answer:

most things would melt

Explanation:

such as glaciers and ice caps in the arctic and Antarctic, causing many floods etc.

ur welcome

The volume of water used is 500cm^3.

The volume of water used.

NaOH concentration in mol/dm^3=NaOH concentration in g/dm^3/molar mass of NaOH.

M of NaOH=23+16+1=40

M=40 g/mol

0.2mol= concentration of NaOH in g/dm^3/40g/mol

=0.2mol/dm^3*40g/mol

=8g/dm^3

we know that,

1dm^3=1000cm^3

4.00g of NaOH will be dissolved in 4g*1000cm^3/8g

=500cm^3 of water

So, the volume of water used is 500cm^3.

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Answer:

20cm³

Explanation:

Volume = Molarity*number of moles

number of moles = Mass given/Molar mass

number of moles= 4.00g/40.0g

number of moles= 0.1mols

thus:

Volume= 0.200mol/dm³*0.1mol

Volume= 0.02dm³(20cm³)

The entropy  is -3.65 and -0.049 J per kelvin per mole respectively are the entropy of an insulated tank.

Entropy is a measure of randomness in a system. It is a state function. It can be denoted by heat supplied for a reversible system per temperature.

The final pressure will be the partial pressure of each gas in the mixture.

a) Partial pressure of nitrogen = mole fraction of nitrogen x total pressure = (0.79 mol) × (1 + 1 bar)/(0.79 + 0.29 mol) = 1.46 bar

Partial pressure of oxygen = mole fraction of oxygen x total pressure = (0.29 mol) ×(1 + 1 bar)/(0.79 + 0.29 mol) = 0.54 bar

Therefore,

ΔS of nitrogen= -R ln1.46 = -0. 38R

∆S of oxygen= -R ln 0.54= -0. 61R

ΔSuniv=−(0.79mol/0.79+0.29mol)×0.38 R−(0.29mol/0.79+0.29mol)×0.61

R=−0.27 R−0.16

R=−0.44

R=−3.65JK−1mol−1

(b) Partial pressure of nitrogen = mole fraction of nitrogen x total pressure = (0.79 mol) × (2 + 1 bar)/(0.79 + 0.29 mol) = 2.19 bar

Partial pressure of oxygen = mole fraction of oxygen x total pressure = (0.29 mol) × (2 + 1 bar)/(0.79 + 0.29 mol) = 0.80 bar

ΔS of nitrogen gas=−Rln1.46=−0.09R

ΔSof sulphur oxide =−Rln0.54=0.22R

ΔSuniv=−(0.79mol/0.79+0.29mol)×0.09R+(0.29mol/0.79+0.29mol)×0.22

R=−0.066 R+0.060

R=−0.049JK−1mol−1

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Five liters of hydrogen gas are stored at a pressure of 400 torrs. If the temperature does not change, then the volume of the gas would be 8 liters when the pressure is decreased to 250 torrs.

It is an imaginary gas for which the volume occupies by it is negligible, this gas does not exist in a practical situation and the concept of an ideal gas is only the theoretical one,

Using the Boyle's law for the given problem,

P₁V₁=P₂V₂

400 × 5 = 250 × V₂

V₂ = 400 × 5 / 250

    = 8 Litres

Thus, if the temperature does not change the volume of the gas would be  8 Litres.

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Considering the definition of atomic mass, isotopes and atomic mass of an element,  the isotope with masses of 62.939598 amu and 64.927793 amu have percent abundances of 69.80% and 30.20% respectively.

The atomic mass (A) is obtained by adding the number of protons and neutrons in a given nucleus of a chemical element.

The same chemical element can have the same atomic numbers, but the number of neutrons is different. These atoms are called isotopes of the element.

The atomic mass of an element is the weighted average mass of its natural isotopes, taking into account the relative abundance of each of them.

In this case, you know:

The percent abundance can be calculated as:

62.939598 amu× (x%÷100%) + 64.927793 amu× [(100-x)%÷100%]= 63.54 amu

Solving:

62.939598 amu× x+ 64.927793 amu× (1-x)= 63.54 amu

62.939598 amu× x+ 64.927793 amu× 1- 64.927793 amu× x= 63.54 amu

62.939598 amu× x- 64.927793 amu× x= 63.54 amu - 64.927793 amu× 1

-1.988195 amu× x= -1.387793 amu

x= (-1.387793 amu)÷ (-1.988195 amu)

x= 0.6980= 69.80%

Then, (100-x)%= (100 -69.80)%= 30.2%

Finally, the isotope with mass of 62.939598 amu has a percent abundance of 69.80% and the isotope with mass of 64.927793 amu has a percent abundance of 30.20%.

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Molality (W) is the ratio of the amount of substance of a solute (in moles – n) to the mass in kilograms of the solvent (m1). It can be calculated by the following formula:

W = n/m1

Step 1 - Let's discover how many moles of sodium fluoride is needed first.

Let's transform 600 g of water to kilograms:

1 g = 0.001 kg

600 g = 0.6 kg

W = 0.600m

m1 = 0.6

0.600 = n/0.6

n = 0.36 moles of sodium floride

Step 2 - Let's transform 0.36 moles of NaF into grams. Let's use the following formula: mass = moles x molar mass

molar mass of NaF = 42 g/mol

mass = 0.36 x 42

mass = 15.12 g

Answer: 15.12 g of NaF

The number of moles of k I o 3 kiox3 titrated is 2.392 x 10^-4 mol.

Concentration is the abundance of a constituent divided with the aid of the total quantity of a combination. Numerous sorts of mathematical descriptions may be prominent: mass concentration, molar concentration, number awareness, and volume awareness.

Concentration is a totally common idea used in chemistry and related fields. it is the measure of ways much of a given substance there is mixed with another substance.

Given : concentration of KIO3 = 0.0100 M

volume of KIO3 = 23.92 mL = 0.02392 L

moles of KIO3 titrated = (concentration of KIO3) * (volume of KIO3 in Liters)

moles of KIO3 titrated = (0.0100 M) * (0.02392 L)

moles of KIO3 titrated = 2.392 x 10^-4 mol

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To solve this question we need to know the concept behind half life. Decay of radioactive element always comes under first order kinetics. Three half-lives have passed since the rock formed.

Half life tells about the time at which the radioactive material decays to half of its initial concentration.

Mathematically the the total number of half life can be calculated as

[tex]\rm \frac{t}{t_{1/2}} =-\frac{ln\frac{N_{t}}{N_{0}} }{ln 2}[/tex]

Nt= amount of the isotope that has not yet decayed after a time t

N₀= initial amount of the isotope

t=the time

[tex]t_{1/2}[/tex] = the half-life

Substituting the given values in the above equation

[tex]\rm \frac{t}{t_{1/2}} =-\frac{ln\frac{125}{100} }{ln 2}[/tex]

Solving this we get

3[tex]t_[1/2}[/tex]= t

Therefore, three half-lives have passed since the rock formed.

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A calibration curve is used to calculate the limit of detection and the limit of quantitation, as well as the concentration of an unknown material.

The concentration of an unidentified drug can be determined using a calibration curve. Researchers and developers can use these curves to determine where an unidentified substance plots by comparing them to data points of known drugs at various doses.

A calibration curve is used to calculate the limit of detection and the limit of quantitation, as well as the concentration of an unknown material. The instrument response to a series of standard samples at various concentrations is used to produce the curve.

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Answer:

The Stroop effect is a simple phenomenon that reveals a lot about how the how the brain processes information.

Answer: The Cerebral Cortex

Explanation: Most information processing takes place here!

Adding buffering compounds to neutralize acids is used to address acid mine drainage.

Therefore, the correct option is C.

Adding lime or other alkaline materials to neutralize the acidity of the soil, as well as adding uncontaminated topsoil, planting vegetation, and modifying slopes to stabilize the soil and reduce surface water infiltration into the underlying contaminated material, are some of the common methods for cleaning up contaminated land. The most commonly used technique for treating AMD contamination is the use of alkaline reagents like lime, limestone, sodium carbonate, or sodium hydroxide. The purpose of this process is to neutralize acidic water and prevent the precipitation of heavy metals.

Acid mine drainage (AMD) is a global problem that has negative effects on the ecosystem. Because of its high acidity and high concentration of heavy metals and metalloids, AMD is harmful to both plants and animals as well as to people. Traditional AMD therapies have been in use for a very long time.

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The presence of partial charges in a liquid enables the liquid to split the bonds of the salt when dissolved in it. On the other hand, in the absence of partial charges, the liquid won't be able to break bonds apart and dissolve salts in it.

How a liquid dissolves things?

In a liquid such as water the charges are arranged in a such a way that generates partial positive and negative sides on hydrogen and oxygen atoms giving rise to polarity.

So when a substance such as salt is dissolved in water, the partial positive charge attracts the negative side of the salt with a definite force while partial negative charge of liquid pulls the positive charges apart.

In general, the partial charges of the liquid pull apart the charges of the added substance which results in breaking their chemical bonds and dissolving them.

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Answer:

91.12 gram

Explanation:

Number of moles of Ammonia = 5.36

Molecular Mass of Ammonia = 14 + 3 × 1 = 17 gram/mol

Mass = Number of moles × Molecular mass

Mass = 5.36 mol × 17 gram/mol = 91.12 gram

Water is the most abundant substance in earth. Water is a compound because it made of a number of H₂O molecules. Water is a homogeneous compound.

Compounds are substances formed by chemical bonding of two or more elements. All the molecules in the compounds will be identical. For example CO₂ where one carbon and two oxygens covalently bond together to form the compound.

Each compound is made of a number of molecules. Thus molecules are the basic units of compounds like we say as for atoms for every substances.

There are different types of compounds based on the type of bond and number of atoms etc namely ionic compounds, covalent compounds, coordination compounds etc.

Water contains two hydrogen atoms and one oxygen thus forms one molecule of water. Similar kinds of molecules joins together to form the compound.

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Answer:3.381 X 10^(-11)

Explanation:

The formula for buoyant force is F = -Volume*density*gravitational acceleration. Convert volume and density to SI units and then apply them in the formula where gravitational acceleration is 9.8m/s^2. Done

Answer:

1.25 moles(N) of NaOH are present in 1000 gm of water.

and 1000gm = 1L

Answer:

Tc

Explanation:

You just have to follow the rows with the exponents. Just remember that when we get to d, the number in the front is a period lower. Hope this helps!

According to the research, the correct option is d. Fernando is currently going through Detoxification process in which his body is cleared of drugs.

This is the treatment aimed at restoring the body's physiological homeostasis after it has been disturbed by the consumption of psychotropic substances as drugs.

In this sense, this process is carried out under the supervision of specialists in the treatment of addictive behaviors.

Therefore, we can conclude that Detoxification is a process of eliminating drugs or substances harmful to health to achieve physiological stability in the body.

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Among the given options, the option A which is A person's weight on the moon is the less than on the Earth, due to the force of gravity, is true.

The weight of a person is usually one-sixth less than their Earth's weight. Only the value of weight fluctuates from Earth to the moon, whereas the mass stays the same on both earth and moon.

This happens due to the gravitational force of the moon. Moon is smaller than the Earth, therefore it has low gravitational forces. Moon's gravitational force leads to the difference in the weights on the Earth and the moon.

The moon of Earth has comparitively less amount of mass than Earth. It is not only small in size than but it also is not as dense as earth. It is only 60 % dense which leads to lower gravitational pull, hence leading to difference in the weight.

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Both transition metals and alkali metals are good conductors of heat and electricity, react with water, and are easily oxidized.

The alkali metals are elements of group 1 which are lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr).  They are also known as the s-block elements because they have their outermost electron in an s-orbital.

The alkali metals are shiny, soft, highly reactive metals and readily lose their outermost electron to create cations with charge +1. They can tarnish rapidly in the air due to oxidation by atmospheric moisture and oxygen.

Transition elements or transition metals are elements that have partially filled d-orbitals. An element having a d-subshell that is partially filled with electrons or can form stable cations with an incompletely filled d orbital.

Any element present in the d-block of the modern periodic table which consists of groups 3 to 12, is considered to be a transition element. For example, the mercury in the +2 oxidation state, corresponds to an electronic configuration of (n-1)d¹⁰. Many paramagnetic compounds are formed by transition metals because they have unpaired electrons in the d orbital.

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