Which of the following materials is the least porous?

loosely packed gravel
unsorted sand and rock
large pebbles and boulders
sorted sand and rock

The magnet can cause the alignment of electron domains in the metal screw driver on rubbing, causing magnetism.

The magnetism in a permanent magnet is produced by magnetic moments of electrons in the magnet's constituent material. The material's atoms are each like tiny magnet bars. As a result of the quantum mechanical effect, the majority of these tiny magnets now prefer to align in a single direction to form domains, consequently magnetizing the entire substance.

Electrons exist in magnetic metals as well, although they are arranged differently. A strong magnet has a magnetic field strong enough to cause residual magnetism in the metal screwdriver by aligning the domains in it on rubbing with the metal.

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If the bond energy between atoms is very high the the bond between the atoms is strong.

Chemical bonds are formed wen two atoms are combined together. The chemical bonds are responsible for holding the atoms together. These chemical bonds could be ionic or covalent in nature. Coordinate bonds have hybrid behavior between ionic and covalent bond types.

We know that the bond energy refers to the energy that must be supplied in order to break the bonds. A high bond energy implies that it takes a whole lot of energy to break the bond. If it takes a lot of energy to break the bond, then the bond must be a strong bond which holds the two atoms together in the compound. Hence, if the bond energy between atoms is very high the the bond between the atoms is strong.

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The positive Biuret test indicates the presence of Peptide bond in proteins.

How to do Biuret test for proteins?

Follow these simple steps if you want to know practically:

Step 1: Take a 3 clean and dry test tubes.

Step 2: Add 1/2 ml of test solution to one test tube, albumin for another, and distilled water to third test tube.

Step 3: Add 3-4 drops of Biuret reagent to each test tube.

Step 4: Shake wee and let it be for 4-5 minutes.

Step 5: Observe the colour changes.

Peptide bonds are (C - N ) bonds present in proteins. The Biuret reagent colour is Pale blue and when you test for protein, if the solution contain protein, when you add the Biuret reagent it will turns to Purple. If there is no protein then the colour remains same.

The Biuret reagent is made up of Hydrated copper sulfate, sodium hydroxide, and Rochelle salt (sodium-potassium tartrate).

Peptide bond is also referred to as Amide bonds, it is formed between the Nitrogen atom of one amino acid and the Carbonyl carbon of second amino acid.

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Answer:

C.) 1345.5 J

Explanation:

To find the energy, you need to use the following equation:

Q = mcΔT

In this equation,

-----> Q = energy (J)

-----> m = mass (g)

-----> c = specific heat (J/g°C)

-----> ΔT = change in temperature (°C)

The specific heat of aluminum is 0.89 J/g°C. You can plug the given values into the equation and solve.

Q = mcΔT

Q = (150 g)(0.89 J/g°C)(10 °C)

Q = 1335

*It is up to you whether you wish to trust this answer. My answer may be slightly different due to using a different specific heat.

Answer:

A

Explanation:

14=pH + pOH

pOH= 14 - 2

pOH= 12

pOH= -log[OH]

[OH]= 10^-12

=1×10^-12

Answer:

Number of neutrons is equal to 148.

Answer:

uestion

Answers 27

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I think we make a mistake when we consider that data are qualitative if they come from applying qualitative methods and techniques or if they are collected in qualitative researches. I think we make the same mistake when we consider quantitative all data collected through, for example, questionnaires.

I think we have to consider the qualitative or quantitative character of data looking exclusively at data. Are they numeric? Are they textual or visual?

I think (as Traian Rotariu argues) that quantitative data are numeric and that qualitative data are textual or visual and that we could gather quantitative and qualitative data with each and every method and technique being it qualitative or quantitative.

For example most of the data gathered with questionnaires are qualitative in their primary form: opinions, gender, preferences etc. and just a few are quantitative in their primary form: income, age, children's number And more

Nuclear reactions include a change in the nucleus of an atom, which typically results in the production of a new element. Contrarily, chemical reactions only require the rearrangement of electrons and do not affect the nuclei; rather, they entail changes in bonding.

What is a nuclear reaction & a chemical reaction?

Therefore it is concluded that option (B) is correct.

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42 grams of NaOH are needed to make a 250.0 mL or a 4.2 M NaOH solution (option C).

The mass of a substance can be calculated by multiplying the number of moles by its molar mass.

However, the number of moles of NaOH can be calculated using the following formula;

Molarity = no of moles ÷ volume

no of moles = 0.250L × 4.2 = 1.05mol

Hence, the mass of NaOH can be calculated as follows:

mass = 1.05 mol × 40g/mol = 42g

Therefore, 42 grams of NaOH are needed to make a 250.0 mL or a 4.2 M NaOH solution.

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The name of the disaccharide above is sucrose

Disaccharides are substances which are composed of two molecules of simple sugars or monosaccharides linked to each other.

Below are some examples of disaccharides:

So therefore, the name of the disaccharide above is sucrose

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Explanation:

we can use the "ideal gas law" :-

PV = nRT

p :- pressure ( pa )

V :- Volume ( m³ )

n :- amount of substance ( mol )

R :- Ideal gas constant ( 8.314 Jmol-¹ K-¹ )

T :- Temperature ( K)

Answer: I think it's B.

Explanation:

The second ionization energy is always the highest ionization energy. Ionization energy is the energy required to remove an electron from an atom in its gaseous state. Hence the correct option is A.

The first ionization energy is the energy required to remove the first electron from an atom. The second ionization energy is the energy required to remove the second electron from an atom that has already lost one electron.

The first ionization energy is always lower than the second ionization energy because the first electron is easier to remove because it is not as strongly attracted to the nucleus.

Once one electron has been removed, the remaining electrons are more strongly attracted to the nucleus, making it more difficult to remove the second electron.

Therefore, option A) 2nd Ionization Energy is correct.

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m(O2)=50g

m(H2)=50g

m(H2O)-?

n2(H2)-?

2H2 + O2 = 2H2O

n(O2)= m (O2)/M(O2) =50g / 32 g/mol= 1,56 mol.

n(H2)= m (H2)/M(H2) =50g / 2 g/mol= 25 mol.

Since oxygen gas is the limiting reactant,

n(O2)< 2 n(H2) from reaction.

n(H2O)= 2n(O2)= 2n (H2 reac.)=2*1,56 mol=3,12mol.

m(H2O)=n(H2O)*M(H2O)= 3,12mol* 18 g/mol.

n2(H2)= n(H2) - n (H2 reac.)=25mol - 3,12mol=21,88mol.

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C₁₂H₂₂O₁₁

1 )

Molar mass = 12 x 12 + 22 x 1 + 11 x 16

= 144 + 22 + 176

= 342 g

2 )

100 mL of 1.0 M will contain 1.0 x0.100 = .1 mole of sucrose

0.1 mole of sucrose = 0.1 x 342 g = 34.2 g of sucrose.

So , mass of sucrose required is 34.2 g .

3 )

100 mL of .5 M sucrose = .100 x .5 mole of sucrose

= .05 mole of sucrose

.05 mole of sucrose = .05 x 342 g = 17.1 g of sucrose .

So , mass of sucrose required is 17.1 g .

Collisions between gas particles are elastic; there is no net gain or loss of kinetic energy this postulate of Kinetic Molecular Theory best explain that how this is possible.

Hence, Option B is correct answer.

The Kinetic Molecular Theory or KMT states that gases are composed of a large number of particles. In these particles are much smaller than the distance between particles. No attraction or repulsion between these particles.

The postulates of kinetic theory of gases are:

Collisions between gas particles or collisions with the vessel walls are perfectly elastic. None of the energy of a gas particle is lost when it collides with another particle or with the walls of the vessel.

Thus from the above conclusion we can say that Collisions between gas particles are elastic; there is no net gain or loss of kinetic energy this postulate of Kinetic Molecular Theory best explain that how this is possible.

Hence, Option B is correct answer.

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Answer:

1.) ⁴₂He

2.) ⁶₂He

3.) ²⁴²₉₄Pu

4.) ¹₀n

Explanation:

The superscript represents the mass number, which is the total amount of protons and neutrons in an element.

The subscript represents the atomic number, which is the total amount of protons in an element.

You can identify the element based on the atomic number. For instance, all atoms with a subscript/atomic number of 2 must always be helium (He). An element with an atomic number of 0 is represented by the symbol "n". The mass number and atomic numbers must be equal on both sides of the reaction.

1.) ¹₁H + ³₁H  → ⁴₂He

    -----> Mass Number: 1 + 3 = 4

    -----> Atomic Number: 1 + 1 = 2

2.) ⁹₄Be + ¹₁H → He + ⁶₂He

    -----> Standard helium (He) has a mass number of 4 and an atomic number of 2

    -----> Mass Number: 9 + 1 - 4 = 6

    -----> Atomic Number: 4 + 1 - 2 = 2

3.) ²³⁹₉₂U + ⁴₂He →  ²⁴²₉₄Pu + ¹₀n

    -----> Mass Number: 239 + 4 - 1 = 242

    -----> Atomic Number: 92 + 2 - 0 = 94

4.) ²⁷₁₃Al + ¹₀n → ²⁴₁₁Na + ⁴₂He

    -----> Mass Number: 24 + 4 - 27 = 1

    -----> Atomic Number: 11 + 2 - 13 = 0

Answer:

C

Explanation:

more products are formed

The amount of the nitrogen gas, N₂ molecules present is 2.68×10²² molecules

1 mole of N₂ = 6.02×10²³ molecules

We'll begin by calculating the number of mole of N₂. This can be obtained as follow:

Mole = mass / molar mass

Mole of N₂ = 1.25 / 28.02

Mole of N₂ = 0.0446 mole

From Avogadro's hypothesis,

1 mole of N₂ = 6.02×10²³ molecules

Therefore,

0.0446 mole N₂ = 0.0446 × 6.02×10²³

0.0446 mole N₂ = 2.68×10²² molecules

Thus, the molecules of N₂ present is 2.68×10²² molecules

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Characteristics of reliable scientific explanations are present in the development of the atomic theory in the given passage.

Atomic theory is the scientific theory that matter is composed of particles called atoms.

The discoveries of subatomic particles such as;

all contributed in the development of the atomic theory.

From the information given in the passage J.J. Thomson experiment gave rise to atomic model while Rutherford, Geiger and Ernest Marsden, performed the experiment that discovered nucleus and proton.

Thus, characteristics of reliable scientific explanations are present in the development of the atomic theory in the given passage.

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Answer:

b.) Br and Br

Explanation:

A covalent bond occurs when electrons are shared between two atoms causing them to form a bond.

A "pure" covalent bond refers to a nonpolar covalent bond. In these bonds, the electrons are shared equally between two atoms as a result of the absence of an (or very small) electronegativity difference. The purest covalent bond would therefore be between two atoms of the same electronegativity. Two bromines (Br) have the same electronegativity, thus making it the purest covalent bond.

Polar covalent bonds occur when electrons are shared unequally between two atoms. There is a larger electronegativity difference between the two atoms, but not large enough to classify the bonds as ionic. In this case, a.) and c.) are polar covalent bonds and d.) is an ionic bond.

Explanation:

The heat needed is (-) 14760 Joules because the ice is cooling.

The term heat refers to a form of energy that can be observed as a result of temperature difference between two bodies. We can recall that heat always flows from the hotter to the cooler body.

Given that the heat added to a substance can be calculated by the use of H = mcdT

Where;

H = heat

m = mass

c = specific heat capacity

T = temperature change

Hence;

H = 150 g * 2.03 Jg∘C * (-63 - (-15))

H =  (-) 14760 J

Hence the heat needed is (-) 14760 Joules because the ice is cooling.

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Answer:

v = 2.141 ml

Explanation:

we can use the "ideal gas law" :-

p :- pressure ( pa )

V :- Volume ( m³ )

n :- amount of substance ( mol )

R :- Ideal gas constant ( 8.314 Jmol-¹ K-¹ )

T :- Temperature ( K)

Answer:

1.45 mol/kg

Explanation:

nilered videos

Answer:

1.47 m

Explanation:

The molality can be found using the following equation:

Molality = moles solute / mass (kg) solvent

In this case, NaCl is the solute and H₂O is the solvent. To find the molality, you need to (1) convert grams NaCl to moles (via the molar mass), then (2) convert grams H₂O to kilograms, and then (3) calculate the molality.

(Step 1)

Molar Mass (NaCl): 22.990 g/mol + 35.453 g/mol

Molar Mass (NaCl): 58.443 g/mol

 30 grams NaCl                 1 mole
--------------------------  x  ------------------------  =  0.513 moles NaCl
                                      58.443 grams

(Step 2)

1,000 grams = 1 kg

350 grams H₂O                   1 kg
--------------------------  x  -----------------------  =  0.35 kg H₂O
                                      1,000 grams

(Step 3)

Molality = moles solute / mass (kg) solvent

Molality = 0.513 moles NaCl / 0.35 kg H₂O

Molality = 1.47 m

Benzene, C6H6 is miscible with hexane (C6H14)  but iron (IIl) nitrate, and Sulfuric acid, H2SO4Fe(NO3)3 are not miscible with hexane (C6H14)

Since organic or non polar dissolves in nom polar solvent.here both benzene and hexane (C6H14) are non polar solvents.But iron (IIl) nitrate, Fe(NO3)3 and Sulfuric acid, H2SO4 are inorganic and polar, therefore cannot dissolve with non polar solvent like hexane.

Miscible is a flowery heard that oil and water aren't very miscible substances, while seltzer and orange juice are miscible and scrumptious.Miscible beverages are also described as liquids that can blend to form a homogeneous solution. Miscible drinks generally blend with out limit, meaning they may be soluble at all quantities.

Miscible approach the materials blend completely. If  substances are miscible, they're also absolutely soluble in each other no matter the order of creation. for example, tetrahydrofuran and water are miscible.

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From the calculations, the equilibrium constant is 216. Option B

The equilibrium constant can depict the amount of reactants that is converted into products at a given time. We know that if thus number is large and positive, then it means that the reaction would proceed to the right.

Thus, we have the equation of the reaction as; CO(g) + Cl2(g) <--> CoCl2(g) and we know that;

K = [CoCl2]/ [CO]  [Cl2]

[CoCl2] = concentration of CoCl2

[CO] = concentration of CO

[Cl2] concentration of Cl2

Substituting the values into the equation;

K = 0.14/  1.2 x 10-2 *  0.054

K = 216

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Answer:

See below

Explanation:

Calcium and chlorine are the reactants .....  they 'react' in a chemical reaction to form the compound calcium chloride .