The cutoff frequency for a certain
element is 1.22 x 1015 Hz. What is its
work function in eV?
Hint: 1 eV 1.60 x 10-19 J
[?] eV

Answer:

12 seconds

Explanation:

Time taken by 50cm³ of oxygen to diffuse from pinhole

= 1 minute = 60 seconds

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[tex] \textsf{ Rate of oxygen} \sf (O_2) = \frac{50}{60} [/tex]

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Let time taken by 50cm³ of hydrogen to diffuse from pinhole = t seconds

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[tex] \textsf {Rate of hydrogen } \sf(H_2) = \frac{50}{t} [/tex]

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According to the formula

[tex] \sf \frac{Rate \: of \: hydrogen(H_2)}{Rate \: of \: oxygen(O_2) } = \sqrt{ \frac{Molar \: mass \: of \: O_2}{Molar \: mass \: of \: H_2} } [/tex]

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[tex] \large \sf \frac{50}{t} \div \frac{50}{60} = \sqrt{ \frac{\cancel{32}\small 16}{\cancel2} } \\ \\ \sf \large \frac{ \cancel{50}}{t} \times \frac{60}{ \cancel{50}} = \sqrt{16} \\ \\ \sf \large \frac{60}{t} = 4 \\ \\ \sf \large \frac{ \cancel{60} \: \small12}{ \cancel4} = t \\ \\ \large \underline{ \boxed{ \tt t = 12 \: seconds}}[/tex]

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Answer:

=> 119.4597 g

Explanation:

From our question, we have been provided with the molarity of the resultant solution.

We know that, molarity of a solution is contained in 1 L or 1000 cm³ of solution.

Hence we have 1.50 moles in 1000 cm³.

Also, we know that, 1 cm³ equivalent to 1 g for water.

Thus, from our question we have 995 cm³ of water.

Lets now solve our problem;

1.5 moles are contained in 1000 cm³

x moles are contained in 995 cm³

Cross multiply

[tex]x \: moles \: = \frac{(995 {cm}^{3} \times 1.5 \: moles )}{(1000 {cm}^{3} )} \\ = \frac{1492.5 \: moles}{1000} \\ = 1.4925 \: moles[/tex]

1.4925 moles of NH4NO3 are required to be dissolved in water.

To find the mass of solute (NH4NO3) we use the formula;

Mass = RFM (Relative Formula Mass) x Number of moles

[tex] = 80.04 \: \frac{g}{mol} \times1.4925 \: mol \\ = 119.4597 \: g [/tex]

Therefore the mass of NH4NO3 needed to be dissolved in 995 g of water is 119.4597 g

Answer:

119.4597

Explanation:

Acellus

The temperature is always the same.

Assume we have something in solid phase. As we increase the temperature, the particles on the solid increase their kinetic energy, thus, the particles move more.

This causes that the volume of the object increases (for example when we heat up a metal and it dilates) and this keeps happening until we reach a critical point, when we are near a change of phase.

At this point the energy given is not used to increase the temperature of the object, but is used to "break" bonds in such a way that the particles are more free than before.

When all these bonds are "broken" the change of phase is completed, and in the case of the solid, we go from solid phase to liquid phase.

So, the temperature is always the same at the beginning of a change of state compare with the temperature at the end of the change

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Answer:

31536000

Explanation:

There are 31536000 seconds in a day.

60s x 60min x 24hrs x 365 days = 31536000sec

Rutherford model task 1 is not supported by Thomson’s experimental evidence.

The atom consists of matter that may be split without releasing electrical charges.

It's also the smallest unit of matter with chemical element features. As a result, the atom is the fundamental unit of science.

The nuclear model of the atom was initially put out by Rutherford. His atomic model states that the majority of an atom's volume is empty,

The nucleus, which contains protons and neutrons, is located in the middle of the atom, and its electrons orbit the nucleus in well-defined paths.

If we discuss the research of some other scientists, like Dalton, Neil Bohr, and JJ Thomson, they are all mostly consistent with Rutherford's findings.

For instance, Dalton's atomic theory presupposed that all atoms are roughly the same size and that atoms interact to generate compounds.

According to Rutherford's theory, atoms have a fixed number of electrons that can be shared to create compounds.

The Bohr model, which posits that electrons orbit the nucleus in certain shells, is also consistent with Rutherford's findings, which gave rise to the idea of shells.

If we discuss Thomson's Plum Pudding Model, it describes atoms as negatively charged particles around a soup of positively charged ions. This is also consistent with Rutherford's findings, which show that positive nuclei are surrounded by negative electrons.

Although Rutherford's model was the greatest atomic model, it nevertheless drew on several earlier investigations and was therefore consistent with the outcomes of earlier models.

Hence rutherford model task 1 is not supported by Thomson’s experimental evidence.

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Based on the calculations, the number of Si atoms in one unit cell is equal to 8 atoms/unit cell.

Mathematically, the volume of a unit cell can be calculated by using this formula:

V = a³

V = (543)³ × (1 × 10⁻¹²)³ × (100)³

Volume, V = 1.60 × 10⁻²² cm³.

Next, we would determine the mass:

Mass = density × volume

Mass = 2.33 × 1.60 × 10⁻²²

Mass = 3.73 × 10⁻²² grams.

Also, we would determine the mass of one silicon atom:

Mass = 28.09/(6.022 × 10²³)

Mass = 4.665 × 10⁻²³ g/atom.

Now, we can calculate the number of Si atoms in one unit cell:

Number = 3.73 × 10⁻²²/4.665 × 10⁻²³

Number = 8 atoms/unit cell.

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9.06 L  is the volume of 0.24 mol oxygen (02) gas at 345 k and a pressure of 0.75.

The ideal gas law (PV = nRT) relates to the macroscopic properties of ideal gases. An ideal gas is a gas in which the particles (a) do not attract or repel one another and (b) take up no space (have no volume).

We know that the ideal gas equation relates the pressure, volume, temperature, and moles of gases as:

PV =nRT

This is a combined gas law based on other gas law like Boyle's law, Charle's law, Avagadro's law, Gay Lussac's law

P =  pressure = 0.75 atm

V = volume = ?

n = moles = 0.24 mol

R = 0.0821 L atm / molK  [gas constant]

T = temperature = 345 K

Putting the values

Volume =[tex]\frac{nRT}{ P}[/tex]

Volume = 0.24 X 0.0821 X 345 / 0.75

= 9.06 L

Hence, 9.06 L is the volume of 0.24 mol oxygen (02) gas at 345 k and a pressure of 0.75.

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Depends on what kind of ions are present in the green solution

Explanation:

Cr3+, a famous green ion can obviously be displayed by a Cu2+ ion

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The statement "According to Le Châtelier's principle, an increase in temperature will shift the equilibrium position toward the products in an endothermic reaction" is definitely true.

Le Châtelier's principle may be defined as transformations in the temperature, pressure, volume, or concentration of a system that will lead to observable and conflicting changes in the strategy in order to accomplish a refreshed equilibrium state.

According to Le Châtelier's principle, an increase in temperature generates the equilibrium to move in the direction of the product of the endothermic reaction, and the decrease in the temperature rationales the equilibrium to move in the direction of the product of the exothermic reaction.

Therefore, it is well described above.

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Any deviation in the image of an object when light passing from one medium to other is assciated to the phenomenon of refraction.

It is the deflection from a straight path undergone by a light ray while passing from one medium (such as air) into another (such as glass) in which its velocity is different.

Basically, the light refraction gives the pencil a slight magnifying effect, which makes the angle appear bigger than it actually is, causing the pencil to look crooked.

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Answer:

Explanation:

Any deviation in the image of an object when light passing from one medium to other is assciated to the phenomenon of refraction.

What is refraction ?

It is the deflection from a straight path undergone by a light ray while passing from one medium (such as air) into another (such as glass) in which its velocity is different.

Basically, the light refraction gives the pencil a slight magnifying effect, which makes the angle appear bigger than it actually is, causing the pencil to look crooked.

After Looking at the pencil from the side of a clear glass or resealable plastic bag filled three-fourths with water, we will see the light bends around the pencil, causing it to look bent in the water.

When the pencil tilt from side to side, It looks so dramatically broken on looking at it from different angles.

We can magically “fix” the broken pencil by changing where the pencil is positioned in the glass.

Among the following options eating an energy bar by a hiker using a chemical potential energy.

Chemical potential energy is the energy stored in the chemical bonds of a substance.

The food we eat contains stored chemical energy.

As the bonds between the atoms in food loosen or break, a chemical reaction takes place, and new compounds are created.

The energy produced from this reaction keeps us warm, helps us move, and allows us to grow

Hence, eating an energy bar by a hiker using a chemical potential energy.

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Answer:

(b)  19.9 moles

Explanation:

To convert from moles Al to moles O₂, you need to multiply the given value by the mole-to-mole ratio of each component. This ratio is constructed via the coefficients in the balanced reaction. The desired unit (moles O₂) should be placed in the numerator to allow for the cancellation of units.

2 Al₂O₃ ----> 4 Al + 3 O₂
                    ^         ^            

26.5 moles Al           3 moles O₂
---------------------  x  ----------------------  =  19.9 moles O₂
                                 4 moles Al

The partial pressure of xenon is 571.5 KPa if the total pressure is 1436.4kPa.

The pressure exerted by a (specified) component in a mixture of gases.

According to Dalton's law of partial pressure, the net pressure of a gaseous mixture is always equal to the sum of the partial pressures of individual gases.

Now we are given that the total pressure is 1436.4kPa

The partial pressure of helium is 348.1kPa

The partial pressure of oxygen is 516.8kPa

Partial Pressure of xenon?

Using dalton's law;

1436.4kPa = 348.1kPa + 516.8kPa + partial pressure of xenon

The partial pressure of xenon is 571.5 KPa.

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Calculate electrons

Total electrons=10+2=12

The element is Magnesium with symbol Mg as atomic no is 12

Additional:-

M:-

Excited state of magnesium

Answer:

a solution: for example when sugar is dissolved in water it becomes a sugar solution

Answer:

T₂ = 26.7 °C

Explanation:

Because you are dealing with pressure and temperature, you can use Gay-Lussac's Law to find the final answer. The equation looks like this:

P₁ / T₁ = P₂ / T₂

In this form, "P₁" and "T₁" represent the initial pressure and temperature. "P₂" and "T₂" represent the final pressure and temperature. You have been given the values for all of the variables but "T₂". Therefore, by plugging these values into the equation, you can simplify to find "T₂".

P₁ = 2.11 atm                   T₁ = 25 °C

P₂ = 2.25 atm                 T₂ = ?

P₁ / T₁ = P₂ / T₂                                            <--- Gay-Lussac's Law equation
(2.11 atm) / (25 °C) = (2.25 atm) / T₂           <--- Plug variables into equation

0.0844 = (2.25 atm) / T₂                            <--- Divide 2.11 by 25

(0.0844) x T₂ = 2.25 atm                           <--- Multiply both sides by T₂

T₂ = 26.7                                                    <--- Divide both sides by 0.0844

The missing components of the neutralisation reaction include the following:

Neutralisation reaction is defined as the type of reaction that leads to the formation of salt and water when an acid and a base reacts.

From the reactions given the missing components are replaced as follows:

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Explanation:

There is an electrostatic force holding the electrovalent bonds together and they're usually structured, whereas in covalent, they are usually free and are only held together by a very weak intermolecular force

Answer:D

Explanation:

A single-replacement reaction occurs when one element replace another in a single compound.

B. One reactant replaces an element in another reactant.

Chemical reactions occur when reactants bond or break apart to form new substances known as the products.

Types of Reactions

There are a few main types of reactions:

All of these are different ways chemical reactions can occur.

Synthesis

Synthesis occurs when two different reactants form one product. This would be a match for answer choice A.

Decomposition

Decomposition occurs when one reactant breaks down, usually through heat, to form 2 different products, which matches answer choice D.

Single Replacement

Single replacement occurs when there are 2 reactants, a substance and an element, and the singular elements replaces one of the elements in the substance to form new products. Since this matches answer choice B, this is the correct answer.

Double Replacement

Finally, double replacement is when there are 2 reactants and each switches an element with the other. This is seen in answer choice C.

For this example remember that [tex]NO_{3}[/tex] is a polyatomic ion and acts as a singular element.

[tex](40.0)(7.426)=\boxed{297.0 \text{ g (to 4 sf)}}[/tex]

Answer:

Adding sugar to water will raise the boiling point and decrease the freezing point of water.

Explanation:

Hope this helps!

If same amount of sugar  added  to the same amount of water and boiled it then boiling point increases.

When sugar added to water it become solution.

Example: If water boils at 100°C then solution with 80%  sugar in 20% of water boils at 112°C.

Since, sugar is non-volatile solute. So, when we boil the solution of sugar in water then water boils easily in low temperature but more  high temperature is required to boil sugar.

The solute which has higher vapor pressure as compare to solution in which it dissolve is called non-volatile solute.

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Answer:

a.  V=44.9mL

Explanation:

For a gas undergoing all of these changes, it will be important to combine Boyle's Law and Charles' Law to form the following equation (if it isn't already known):

[tex]\dfrac{P_1V_1}{T_1}=\dfrac{P_2V_2}{T_2}[/tex]

Where the Temperatures must be measured in Kelvin.

Recall that to convert Celsius to Kelvin, one must add 273 or use the equation [tex]T_C+273=T_K[/tex].

Thus, [tex]T_1=(18.1+273)[K]=291.1[K][/tex]  and [tex]T_2=(12.5+273)[K]=285.5[K][/tex]

To solve for the requested quantity, note that all of the other units match between beginning and end, so we substitute and solve:

[tex]\dfrac{P_1V_1}{T_1}=\dfrac{P_2V_2}{T_2}[/tex]

[tex]\dfrac{(2.61[atm])V_1}{(291.1[K])}=\dfrac{(1.92[atm])(59.9[mL])}{(285.5[K])}[/tex]

[tex]\dfrac{(2.61[atm] \!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!{-----})\bold{V_1}}{291.1[K] \!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!{-----}}*\dfrac{291.1[K] \!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!{-----}}{2.61[atm]\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!{-----}}=\dfrac{(1.92[atm]\!\!\!\!\!\!\!\!\!\!\!{--})(59.9[mL])}{285.5[K\!\!\!\!\!{-}]}*\dfrac{291.1[K\!\!\!\!\!{-}]}{2.61[atm]\!\!\!\!\!\!\!\!\!\!\!{--}}[/tex]

[tex]V_1=44.928677576[mL][/tex]

Accounting for significant digits, [tex]V_1=44.9[mL][/tex]

Heating up a reaction increases the speed of a reaction until the enzyme denatures.

Enzyme denaturation occurs when a biological protein catalyst does not work anymore due to a high temperature that alters its tridimensional conformation.

This cellular process (denaturation) is well known to be one of the main causes of enzymatic failure.

In conclusion, heating up a reaction increases the speed of a reaction until the enzyme denatures.

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The Molar Concentration Of A =0.099 .

The Relative Molar Mass Of A = 35.0129 gm

Given,

Mass of HX = 3.5 g

Moles of solution B ([tex]Na_{2} CO_{3}[/tex]) = 0.05 moles

Volume of HX = 26.10 mL

Volume of Solution B = 25 mL

Molecular weight of solution B = 2(atomic weight of Na )+ atomic weight of C + 3(atomic weight of O)

                 = 2(23) + 12 + 3(16)

                 =106 gm

Equivalent weight of  [tex]Na_{2} CO_{3}[/tex] = molecular weight / 2 = 106 /2  =53 g

Mole = mass / molecular weight

∴0.05 = mass / 106

∴ mass = 5.3 gm [tex]Na_{2} CO_{3}[/tex]

Normality = mass ÷ (equivalent weight × volume of the solution in liter)

                = 5.3 ÷( 53 × 0.025)

                =4 N

So, by using formula ,

[tex]N_{1} V_{1} =N_{2} V_{2}[/tex]

[tex]N_{1}[/tex] = normality of solution B = 4 N

[tex]V_{1}[/tex] = volume of solution B = 25 mL

[tex]N_{2}[/tex] = normality of solution A = ? N

[tex]V_{2}[/tex] =Volume of solution A = 26.1 mL

∴ 4×25 = [tex]N_{2}[/tex] × 26.1

∴[tex]N_{2}[/tex] = 3.83 N

∴ normality of solution A = 3.83 N

from Formula of the normality we can find the equivalent weight of the A

Normality = mass of HX ÷ (equivalent weight × volume of the solution in liter)

3.83 = 3.5 ÷( equivalent weight × 0.0261)

∴equivalent weight = 35.0129 g

In case of HX the electron transfer is 1 ,so equivalent weight = molecular weight ; which is also termed as relative molar mass in given case.

∴The Relative Molar Mass Of A = 35.0129 g

Molar concentration = mass / molar mass

                               = 3.5 / 35.0129

                               = 0.099 mole

∴ The Molar Concentration of A  is 0.099 .

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Answer: The pH of the solution is 5.65

Explanation:

The relationship between the pH and the pOH is that [tex]pH+pOH=14[/tex].

Given this, we can plug in the pOH and subtract that from 14.

[tex]14-pOH=pH\\14-8.35=5.65[/tex]

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Answer:

Give the man above me brainliest

Answer:

ionic bond

Explanation:

Answer:

Ionic bonding

Explanation:

Salt    Na+Cl-       is an example