A hypothesis is _____

A: a law


B: an educated guess


C: a fact


D: always proven

The energy supplied to the charge carriers in a circuit exists measured by the potential difference (or voltage) of a supply.

m = mass of electron = 9.1 x 10⁻³¹ kg

λ = wavelength of electron = 0.29 x 10⁻⁹ m

v = speed of electron

Using de-Broglie's hypothesis

λ m v = h

(0.29x 10⁻⁹) (9.1 x 10⁻³¹) v = 6.63 x 10⁻³⁴

v = 2.9 x 10⁶ m/s

ΔV = Potential difference through which electron is accelerated

q = charge on electron = 1.6 x 10⁻¹⁹ C

Using conservation of energy

(0.5) m v² = q ΔV

(0.5) (9.1 x 10⁻³¹) (2.9x 10⁶) ² = (1.6 x 10⁻¹⁹) ΔV

ΔV = 20.7 volts

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The weight of the column is 1224.73 pounds.

r = 380 mm/2 = 190 mm

r = 0.190 m; a radius of a concrete column

l = 2 m; a length of a concrete column

d = 2.45 Mg/m³; density of a concrete

V = r² × π × l

V = (0.190 m)² × 3.14 × 2 m

V = 0.227 m³; volume of a column

m = d × V

m = 2.45 Mg/m³ × 0.227 m³

m = 0.555 Mg

1 Mg = 1000 kg

m = 555.4 kg; mass of concrete

W = 555.4 kg × 9.8 m/s²

W = 5443.25 N

W = 5443.25 N × 0.225 Ibf/N

W = 1224.73 Ibf; weight of a concrete

The weight of an object is the amount of force acting on the object due to gravity. SI unit for weight is newton (N).

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The Balanced equation is:

[tex]NO_3^- (aq) + 2Zn (s) \rightarrow Zn^2^+ (aq) + 3NO (g)[/tex]

A balanced equation is a chemical reaction in which the overall charge and the number of atoms for each component are exactly equal for both the products and the reactants. In simple words, the mass and charge of each side of the reaction process are equal.

One may balance equations by adhering to some basic guidelines:

1. Verify that all of the equation's formulas are accurate.

2. Focus on just one component at a time.

3. Balancing requires big number addition. A chemical formula cannot have any little numbers changed. If there has to be any balance, place the number before the substance.

4. Recheck each component and repeat step 3 if necessary.

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Yes, a reaction occurs.

When Magnesium nitrate Mg(NO3)2 and iron (II) sulphate (FeSO4) are combined, double displacement reaction takes place.

       AB  + CD →  AD + CB

Ionic equation according to the question-

FeSO4 + Mg(NO3)2 → Fe(NO3)2 + MgSO4

Here, Iron (II) sulphate reacts with Magnesium nitrate to form Iron nitrate and  magnesium sulphate by undergoing double displacement reaction.

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Yes, there is a reaction when iron (II) sulphate (FeSO₄) and magnesium nitrate Mg(NO₃)₂ are mixed.

Double displacement reaction occurs when iron (II) sulphate (FeSO₄) and magnesium nitrate Mg(NO₃)₂ are mixed.

Displacement reaction- When a less reactive element is pushed out of a compound that also contains a more reactive ingredient, the result is a displacement reaction. The less reactive element is now pure and left alone following a displacement reaction.

AB + C → A + CB

whereas,

Double displacement reaction- In a double displacement reaction, two compounds swap cations or anions (ions) to create two new molecules.

AB  + CD →  AD + CB

FeSO₄ + Mg(NO₃)₂ Fe(NO₃)₂ + MgSO₄ is the ionic equation in response to the query.

Here, a double displacement reaction occurs between magnesium nitrate and iron (II) sulphate to produce iron nitrate and magnesium sulphate.  

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On the basis of the characteristics of the "R" group in each amino acid, amino acids can be divided into four general groupings. Polar, nonpolar, electrically charges amino acids are all possible types. The "R" groups on polar amino acids are hydrophilic, meaning they want to come into touch with watery solutions.

What are amino acids?

Organic compounds known as amino acids join with other amino acids to produce proteins. Because the proteins that amino acids create are involved in almost all cellular processes, amino acids are necessary for life. While some proteins serve as structural support, others act as antibodies or enzymes. Although there are hundreds of amino acids in nature, only a set of 20 amino acids are used to make proteins.

On the basis of the characteristics of the "R" group in each amino acid, amino acids can be divided into four general groupings. Polar, nonpolar, electrically charges amino acids are all possible types. The "R" groups on polar amino acids are hydrophilic, meaning they want to come into touch with watery solutions. The hydrophobic (opposite) nonpolar amino acids shy away from contact with fluids. These interactions are crucial for protein folding and provide proteins with their three-dimensional structure.

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When an electron in a hydrogen atom undergoes the transition from the energy level. The wavelength is 97.3 nm.

The separation between similar points in successive waves of a waveform signal that have traveled across space or along a wire.

1 / λ = -1.097 x 107 m-1 ( 1/nf2 - 1/ni2 )

λ = wavelength in m

nf = final energy level = 1

ni = initial energy level = 7

1 / λ = -1.097 x 107 m-1 (1/16 - 1) = 1.097 x 107 m-1 (-0.9375)

1 / λ = 1.028 x 107 m-1

λ = 9.73x10-8 m = 97.3 nm

Thus, the wavelength, in nanometers, of the spectral line is 97.3 nm.

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ion-ion,  is the dominant intermolecular force that determines the solubility of the amine hydrochloride salt of ethyl 4-aminobenzoate in water.

It is standard practice to transform amines into their hydrochlorides in order to increase their water solubility, which might be advantageous for compounds used in pharmaceuticals. More than 200 hydrochlorides are listed as active components in pharmaceuticals in the European Pharmacopoeia. In comparison to free bases, these hydrochlorides might dissolve more easily in the digestive system and be absorbed into the bloodstream faster. Furthermore, many amine hydrochlorides have a longer shelf life than their corresponding free bases.

Amine hydrochlorides are latent forms of a free base, which is more reactive. In this sense, protection is granted by the production of an amine hydrochloride. The hydrochlorides of the amino acids serve as an example of this phenomenon. Shelf-stable glycine methyl ester hydrochloride is easily transformed into reactive glycine methyl ester, a substance.

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The total degrees of freedom for helium are three.

The number of ways that a molecule can move or vibrate in space in gaseous phase is known as degree of freedom. The degree of freedom depends on the total number of atoms and the geometrical structure of atoms.

There are three types of degrees of freedom; rotational, translational and vibrational. The degree of freedom for helium is three for translational motion only.

The degree of freedom for monoatomic is three such in the case of helium. A molecule can have different degrees of freedom for different types. For examples, the degrees of freedom for NH3 is 3 for translational and rotational and six for vibrational.

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The base ionization constant exists as the equilibrium constant for the ionization constant.

The base ionization constant exists as the equilibrium constant for the ionization constant. It is represented as Kb. If the concentration of the solution (C) and the degree of ionization (α)exists known, then the base ionization constant exists measure as follows:

[tex]$K_b=\frac{C \alpha^2}{1-\alpha}$[/tex]

[tex]$K_b=\frac{C \alpha^2}{1-\alpha}$[/tex]

=(0.0800*21%) ²/1-21%

=0.003/1-0.21 =0.0044.

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The mole fraction of glycerol in this solution is 3.58%.

d = 1.037 g/ml; density of the solution

M(HOCH₂CH(OH)CH₂OH) = 92.095 g/mol; molar mass of glycerol

m= 100 ml × 1.037 g/ml

m= 103.7 g; mass of 100 ml of the solution

m(HOCH₂CH(OH)CH₂OH) = 0.16 × 103.7 g

m(HOCH₂CH(OH)CH₂OH) = 16.592 g; mass of glycerol

n(HOCH₂CH(OH)CH₂OH) = 16.592 g ÷ 92.095 g/mol

n(HOCH₂CH(OH)CH₂OH) = 0.180 mol; amount of glycerol

m(water) = 103.7 g - 16.592 g

m(water) = 87.108 g

n(water) = 87.108 g ÷ 18.0153 g/mol

n(water) = 4.835 mol; amount of water

mole fraction = 0.180 mol ÷ (0.180 mol + 4.835 mol)

mole fraction = 0.0358 = 3.58%

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Benzoic acid in the presence of [tex]SOCl_2[/tex] gets converted to benzoyl chloride which further gets converted to benzamide when treated with ammonia. Benzamide gets reduced to benzylamine by [tex]LiAlH_4[/tex].

Steps involved in the preparation of benzylamine from benzoic acid:

Step 1:

Benzoyl chloride is formed on replacement of [tex]-OH[/tex] group with [tex]-Cl[/tex] group when benzoic acid is treated with thionyl chloride.

Step 2:

Benzoyl chloride converts to benzamide by the replacement of [tex]-Cl[/tex] group with [tex]-NH_2[/tex] group on treatment with ammonia.

Step 3:

Benzamide is reduced to benzylamine in the presence of [tex]LiAlH_4[/tex]. The strong reducing agent converts the carbonyl group (C=O) to [tex]-CH_2-[/tex] group.

Benzylamine is a chemical compound that is organic in nature. A primary amine molecule called benzylamine has benzyl as the N-substituent. This colourless liquid that is soluble in water is a popular starter in organic chemistry and is utilized in the manufacturing process of many medications.

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Explanation:

Sodium is a reactive metal, and so can't be extracted by electrolysis of an aqueous solution.

The main ore of sodium is common salt, sodium chloride.

Calcium chloride is added to the purified ore to lower the melting point from around 800°C to around 600°C, so that energy costs are lowered and this is economical because it saves on electricity used in heating.

Change in pH is resisted by a buffer on addition of small amount of acid or base.

When a small amount of a strong acid or base is introduced to a buffer, the change in pH does not occur. This is accurate provided that the quantity of strong acid or base supplied does not significantly outweigh the quantity of conjugate base and conjugate acid already in the buffer. The buffering capacity will exceed if an excessive amount of a strong acid or basic is added.

A buffer is a substance that can withstand a change in pH when acidic or basic substances are added. Small additions of acid or base can be neutralized by it, keeping the pH of the solution largely constant. For reactions that call for certain and stable pH ranges, this is significant. The pH range and capacity of buffer solutions determine how much acid or base can be neutralized before there is a change in pH and how much pH will vary.

A buffer is a unique liquid that prevents significant pH level fluctuations. Each buffer that is created has a specific buffer range and buffer capacity. The quantity of base or acid that may be added to a buffer before the pH starts to noticeably shift is known as the buffer capacity.

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The particular pH at which a given amino acid exists in solution as a zwitterion is called the isoelectric point (pI).

The structure of an amino acid allows it to act as both an acid and a base. An amino acid has this ability because at a certain pH value (different for each amino acid) nearly all the amino acid molecules exist as zwitterions.

If acid is added to a solution containing the zwitterion, the carboxylate group captures a hydrogen (H+) ion, and the amino acid becomes positively charged. If base is added, ion removal of the H+ ion from the amino group of the zwitterion produces a negatively charged amino acid.

Amino acids undergo reactions characteristic of carboxylic acids and amines. The reactivity of these functional groups is particularly important in linking amino acids together to form peptides and proteins, as you will see later in this chapter. Simple chemical tests that are used to detect amino acids take advantage of the reactivity of these functional groups.

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Answer:

a

Explanation:

I'll explain along side with potassium (k) and Calcium (Ca). the unit for scandium is SC

Sc = 21

Ca = 20

K =19

k = 1s²,2s²,2p⁶,3s²,3p⁶,3d⁰,4s¹

Ca = 1s²,2s²,2p⁶,3s²,3p⁶,3d⁰,4s²

Sc = 1s²,2s²,2p⁶,3s²,3p⁶,3d¹,4s²

if you notice above Sc has 3d¹ while Ca has 3d⁰. This is because Sc is a transition metal

Transition metals are metals whose d-orbital aré partially filled with electron

Diagram B represents the plum pudding model of the atom.

Plum pudding model was proposed by Thomson. He knew that atoms are of neutral charge. Therefore, he reasoned that there must be a source of charge within the atom to counterbalance the charge on the electrons. This led Thomson to propose that atoms may well be described as negative particles floating within a soup of diffuse charge.

This model is usually called the pudding model of the atom, because of the actual fact that its description is incredibly just like Christmas pudding, a well-liked English dessert.

However, Thomson’s atomic model did not explain how the electric charge holds on the electrons inside the atom. It also did not explain an atom’s stability.

The theory failed to mention anything about the nucleus of an atom.

It was unable to elucidate the scattering experiment of Rutherford.

Even though Thomson’s atomic model was inaccurate and had some drawbacks, it provided the bottom for several other atomic structure models afterward. it's one in all the muse models that led to significant and revolutionary inventions later.

Therefore, option B is the diagrammatic representation of plum pudding model.

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The properties of an ionic compound are as follows:

Thus, the correct options for this question are C and D.

An Ionic compound may be defined as a type of chemical compound that is significantly composed of ions that are held together by electrostatic forces referred to as ionic bonding.

The properties of ionic compounds are determined by the process through which they dissociate from one another when they dissolve in water. For example, NaCl. They are good conductors of heat and electricity.

Therefore, the correct options for this question are C and D.

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All halides (nonmetals) could form an ionic compound with magnesium with the formula mgx2.

What are ionic compounds?

A chemical compound known as an ionic compound in chemistry is one that contains ions bound together by the electrostatic forces known as ionic bonding. Despite having both positively and negatively charged ions, or cations and anions, the molecule is generally neutral.

The proportional size of the cations and anions determines how an ionic molecule is structured. Salts, oxides, sulphides, hydroxides, and the majority of inorganic compounds are examples of ionic compounds. The electrostatic forces of attraction between positive and negative ions hold together ionic solids.

All halides or other non metallic ions like OH- that require one electron to satisfy their octet  that is noble gas configuration will form compounds with the formula MgX2.

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When student places two charged objects near each other. The objects repel each other. The student concludes that the objects must both be negative .

YES, the conclusion is accurate according to rule like charges repel each other for example negative to negative, positive to positive and unlike charges attracts each other for example negative to positive or positive to negative.

It is governed by Coulomb's law how two sets of charges interact. According to the law, two charges held apart will attract or repel one another with a force equal to their product and the square of the distance between them. While items with differing charges attract one another, those with the same charge repel one another.

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A statement which most likely explains why the early atomic models did not include the subatomic particles is that: D. subatomic particles could not be detected with the technology available.

Generally, an atom comprises three (3) distinct subatomic particles and these include the following

Ernest Rutherford performed a set of experiments on atoms in 1910 which has helped several scientists and researchers to better understand the structure of atoms by using gold foil.

In his experiment on structure of atoms, Rutherford directed a beam of small, positively charged particles referred to as alpha () particles at a very thin sheet of gold foil.

However, the early atomic models did not include the subatomic particles is that they could not be detected with the technology available at the time.

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Complete Question:

Ancient atomic models described the atom as a solid sphere with no charge. In the 1800's and 1900's, scientist discovered subatomic particles with charges inside the atoms.

Which statement most likely explains why the early models did not include the subatomic particles?

answer choices

atoms changed over time to develop the subatomic particles

not all atoms contain subatomic particles

subatomic particles move and cannot be counted

subatomic particles could not be detected with the technology available.

When developing prints, Red light doesn’t affect the picture.

The only film you may use is a red light whilst developing it's a far orthochromatic black & white movie which isn't always touchy to crimson mild red seems black in the photographs. photograph resolution is often given in PPI pixels according to the inch. It was how many pixels are displayed in keeping with the inch inside the image. photo decision is a factor that determines picture satisfaction. but the camera sensor processor and even the great lens you're the use of also play an element.

Lighting is a key component in creating a hit picture. lighting fixtures determine now not the handiest brightness and darkness but additionally tone temper and environment. therefore, it's far important to control and control mild efficiently on the way to get the first-rate texture, vibrancy of color, and luminosity in your topics. A safelight is a light source suitable for use in a photographic darkroom. It provides illumination most effective from parts of the visible spectrum to which the photographic cloth in use is almost or absolutely insensitive.

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Answer:

2H+(aq) is the net ionic equation.

The empirical formula of a compound found to contain 7.353 g of Al and 6.547 g of O is Al2O3.

We are given that

Mass of Al = 7.353 g

Mass of O = 6.547 g

To calculate the moles of the compounds, we need to divide the given mass by their molar mass

Moles of Al = 7.353/27 = 0.272

Moles of O = 6.547/16= 0.409

Now we need to divide the moles by the least common number i.e, 0.272.

Moles of Al/0.272 = 0.272/0.272= 1

Moles of O/0.272= 0.409/0.272 = 1.5

Now, to convert these values into whole numbers we should multiply them by 2

Moles of Al = 2

Moles of O = 3

Thus, the ratio of Al:O = 2:3

Hence, the empirical formula of a compound found to contain 7.353 g of Al and 6.547 g of O is Al2O3.

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This means that you must take 2.5ml of the stock solution and make up to mark with 7.5 ml of water. You should add acid to water and not water to acid.

The terms ACID (atomicity, consistency, isolation, and durability) refer to a set of characteristics of database transactions that are meant to ensure data validity despite errors, power outages, and other unforeseen circumstances.

A transaction is a series of database activities that adhere to the ACID principles and can be thought of as one logical operation on the data in the context of databases. For instance, a transfer of money between bank accounts, even when it involves many adjustments like debiting one account and crediting another, is only one transaction.

Building on previous work by Jim Gray, who identified atomicity, consistency, and durability but not isolation when describing the transaction concept, Andreas Reuter and Theo Härder created the acronym ACID in 1983.

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w/w+%+of+an+aqueous+solution+of+ammonia+at+14.3+m,+with+a+density+of+0.900+g/ml.

The molar mass of ammonia is 17g/mol

So, 14.3 mole ammonia =  17×14.3 g = 243.1g

In 1243.3 g solution, ammonia is present = 243.3g

So, in 100 g solution, ammonia is present

= (243.3/1243.3) × 100 g

= 19.57 g

Ammonia here is 19.56% w/w.

What is w/w?

The concentration of a solution can be expressed in a variety of ways. They only differ in terms of the units they utilise, but they consistently express the solute concentration in a specific volume of solution. The solution contains 0.3% (w/w) PCMX, according to the label on the right, where (w/w) stands for weight per weight.

(w/w) The relative amount of solute and solvent present in a solution is indicated by its concentration. The proportion of solute to solvent in a concentrated solution is high.

The concentration of the solution is 14.3 m

So, we can say in 1 kg of solvent (water)  , 14.3 mole solute ( ammonia ) is present.

The molar mass of ammonia is 17g/mol

So, 14.3 mole ammonia =  17×14.3 g = 243.1g

In 1243.3 g solution, ammonia is present = 243.3g

So, in 100 g solution, ammonia is present

= (243.3/1243.3) × 100 g

= 19.57 g

So, here , Ammonia 19.56% w/w.

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If 233.76g NaCl in 1l of water makes a solution of 1M, then the same amount in 5l solution will make 1/5M solution.

What is molarity?

The term "molar concentration" is used to define the concentration of a chemical species, specifically a solute, in a solution. It denotes the quantity of a substance per unit volume of solution. Other synonyms for this phrase include quantity, substance concentration, and molarity.

M = n/V

where,  n = no of moles of solute that is solute concentration

V = volume of solution

and, M = molarity of the solution.

If 233.76g of sodium chloride dissolves in 1 litre of water to form a 1 M solution, then the same amount in 5 litres will form a 1/5 M solution.

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1.5 contains two significant figures i.e. 1 and decimal number 1.5 .

Significant figures are the number of digits in a value, often a measurement, that contribute to the degree of accuracy of the value. We start counting significant figures at the first non-zero digit.

There are 3 rules to determine significant figures ,there are as :

1. Non-zero digits are always significant.

2. Any zeroes between two significant figures digits are significant.

3. A final zero in the decimal portion only are significant.

Hence, 1.5 contains two significant figures .

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The molecular equation for the reaction of aqueous copper(II) chloride and aqueous potassium phosphate:

3CuCl₂(aq) + 2K₃PO₄(aq) → 6KCl(aq) + Cu₃(PO₄)₂(s)

CuCl₂ is the salt copper (II) chloride.

K₃PO₄ is the salt potassium phosphate.

KCl is the salt potassium chloride.

Cu₃(PO₄)₂ is the insoluble salt copper(II) phosphate.

Anhydrous copper(II) phosphate is a blue solid salt.

(aq) is an aqueous solution.

(s) is a solid, insoluble in the water

There are same number of atoms of on both side of the balanced chemical reaction: three copper (Cu), six chlorine (Cl), six potassium (K), two phosphorus (P) and eight oxygen (O) atoms.

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