find the relative atomic mass​

The work function of the metal is obtained as 5.1 eV

The cutoff frequency is the frequency below which photo electric effect can not occur as electrons are not removed from the metal surface.

Now;

fo = 1.22 x 10^15 Hz

Wo = hfo

Wo = 6.6 * 10^-34 * 1.22 x 10^15

Wo = 8.1 * 10^-19 J

If 1 eV = 1.60 x 10-19 J

x eV = 8.1 * 10^-19 J

x = 8.1 * 10^-19/ 1.60 x 10-19

x = 5.1 eV

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Answer:

37 Degrees Celsius

Explanation:

Answer:

-40.0 °C

Explanation:

Change in temperature can be written as [tex]\displaystyle{\Delta T = T_2-T_1}[/tex]. The variables are defined below here:

[tex]\displaystyle{\Delta T}[/tex] means change in temperature.

[tex]\displaystyle{T_2}[/tex] means the final temperature value.

[tex]\displaystyle{T_1}[/tex] means the initial temperature value.

From the question, we know the temperature changes from 65.0 °C to 25.0  °C. Therefore, our initial temperature is 65.0 °C and final temperature is 25.0 °C.

Hence:

[tex]\displaystyle{\Delta T=25.0-65.0}\\\\\displaystyle{\Delta T = -40.0}[/tex]

Therefore, the change in temperature is -40.0 °C.

Answer:

C. It has the same types of atoms on both sides of the reaction arrow.

A chemical equation is a symbolic representation of a chemical reaction; Reactants are represented on the left and the products on the right.

The law of conservation of mass states that in a closed system, mass is neither created nor destroyed during a chemical or physical reaction. The law of conservation of mass is applied whenever you balance a chemical equation. It is also applicable to stoichiometry. A balanced equation demonstrates the conservation of mass by having the same number of each type of atom on both sides of the arrow.

Consider the balanced equation for the combustion of methane.

[tex]CH_4 + 20_2 \implies CO_2 + 2H_2O[/tex]

All balanced chemical equations must have the same number of each type of atom on both sides of the arrow.

In this equation, we have 1 C atom, 4 H atoms, and 4 O atoms on each side of the arrow.

The number of atoms does not change, so the total mass of all the atoms is the same before and after the reaction. Mass is conserved.

The same atoms of the same element that are present in the reactants are also present in the products, according to the rule of conservation of matter.

This leads us to believe that the response to the question is true because: It has the same atom kinds on both sides of the reaction arrow (Option C)

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Answer:

A scientist measures the standard enthalpy change for the following reaction to be -139.5 kj :

h2(g) + c2h4(g)c2h6(g)

based on this value and the standard enthalpies of formation for the other substances, the standard enthalpy of formation of c2h4(g) is _____ kj/mol

Explanation:

Hydrogen ΔHof (kJ/mol) ΔGof (kJ/mol) So (J/mol K)

H2 (g)

0

0

130.7

Carbon ΔHof (kJ/mol) ΔGof (kJ/mol) So (J/mol K)

C2H6 (g)

-84.7

-32.8

229.6

Answer:

27966692

Explanation:

I don't know if this is right or not

Taking into account the definition of Avogadro's number and molar mass, 3.49334×10²² molecules of sucrose are present.

The molar mass of substance is a property defined as its mass per unit quantity of substance, in other words, molar mass is the amount of mass that a substance contains in one mole.

Avogadro's Number or Avogadro's Constant is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023×10²³ particles per mole. Avogadro's number applies to any substance.

In first place, the molar mass of sucrose is 342 g/mole. So, you can apply the following rule of three: If by definition of molar mass 342 grams of the compound are contained in 1 mole, 20 grams of the compound are contained in how many moles?

[tex]amount of moles=\frac{20 gramsx1 mole}{342 grams}[/tex]

amount of moles= 0.058 moles

Now, considering the Avogadro's number, you can apply the following rule of three: If 1 mole of the compound contains 6.023×10²³ molecules, 0.058 moles contains how many molecules?

amount of moleculas= (6.023×10²³ molecules × 0.058 moles)÷ 1 mole

amount of molecules= 3.49334×10²² molecules

Finally, 3.49334×10²² molecules of sucrose are present.

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[tex]\quad \huge \quad \quad \boxed{ \tt \:Answer }[/tex]

[tex]\qquad \tt \rightarrow \:36 \:\: g [/tex]

____________________________________

[tex] \large \tt Explanation \: : [/tex]

The given compound has 3 carbon atoms, so in 1 mole of that compound, there will be 3 moles of carbon atoms.

Mass of each mole of carbon atoms = 12 g

For 3 mole carbon atoms, it will be 12 × 3 = 36 grams

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Answer:

the number off double bonds in a fatty acid chain

The industrial methods of preparing alcohol that is more economical is fermentation.

Fermentation is defined as the industrial method by which starch is converted to ethyl alcohol by using some specific enzymes and microorganisms known as yeast

It is an economical method because the raw material which is starch is readily available.

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Answer:

CO_(2)` molecules removed `= 10^(21)` <br> No. of `CO_(2)` molecules left `= 2.74 xx 10^(21) - 10^(21) = 1.74 xx10^(21)` <br>

Explanation:

Mole and dozen are similar to each other because of the presence of number 12 in both measurements.

The sample of 12 grams of carbon is equal to its one mole and we know that in one dozen, there are 12 numbers. Therefore, we considered mole similar to a dozen.

So we can conclude that Mole and dozen are similar to each other because of the presence of number 12 in both measurements.

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[tex](115.00)(0.25)+(117.00)(0.75)=\boxed{116.50 \text{ u}}[/tex]

Answer:

C. Battery acid burning the floor

Explanation:

C. Battery acid burning the floor

in combustion fire is created

Battery acid burning the floor is NOT an example of combustion occurring.

The answer is option C.

Combustion is a chemical process or a reaction between the gas (Hydrocarbon) and Oxygen. while gasoline and oxygen react it releases warmth and light energy. heat and light energy then result in the flame. So, the system for Combustion reaction is Hydrobcarbon + Oxygen = warmness electricity.

Combustion in daily existence examples is: Burning of wooden or Coal for the family functions. Burning of Petrol or Diesel for using vehicles like vehicles. Combustion of herbal gas or LPG.

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Answer

Number 1. increase

number 2 . decrease

number 3. decrease

Answer:

The unknown metal could be calcium or magnesium.

Explanation:

Displacement of a metal from its chemical reaction is shown by the reaction known as single displacement reaction. The reactivity of metal is determined by the reactivity series. The metals lying above in the series are more reactive than the metals which lie below in the reactivity series.

Metal B is more reactive than metal A.

The metal which easily displaced aluminium will lie above in the series but that same element cannot displace sodium, so it will lie below in the series.

Hence, from the series, we conclude that the unknown metal could be calcium or magnesium.

Answer: It will expand to fill the room.

Explanation:

Gases will expand or compact to fill the available space.

From the equation, we know that for every 2 moles of aluminum consumed, 2 moles of aluminum chloride are produced.

This means that if 0.25 moles of Al react, then 0.25 moles of aluminum chloride are produced.

So, the formula mass of aluminum chloride is:

Thus, 0.25 moles have a mass of:

Balanced

Moles of CaCl_2=0.425mol

1 mol CaCl_2 producees 1 mol LiCl

Moles of LiCl

The equation is

[tex]\\ \tt{:}\dashrightarrow LiOH+CalCl_2\longrightarrow LiCl+Ca(OH)_2[/tex]

1mol of LiCl needs 1 mol CaCl_2

Then

0.425mol of CaCl_2 will produce 0.425mol LiCl

Answer:

For a particular chemical reaction, the enthalpy of the reactants is -400 kJ. The enthalpy of the products is -390 kJ. The entropy of the reactants is 0.2 kJ/K. The entropy of the products is 0.3 kJ/K. The temperature of the reaction is 25oC. What can you conclude about this reaction?

It is exergonic

It is endergonic

it is a redox reaction

It is being catalyzed by an enzyme

Answer:

aldehyde

Explanation:

it ends with "al" of "al"dehyde, always check the end

Answer:

the answer is hormone

Explanation:

because it is

According to the label the true statement about the following substance is option c. It does not pose a health risk

Specially designed labels with particularly specialised adhesive qualities are called "lab labels." In the pharmaceutical or medical industry, as well as in laboratories, they are used for labelling. For the labelling of tubes, test tubes, blood bags, and other types of vessels, special laboratory labels are created.

Labels on chemicals

The identify of the hazardous chemical(s) in the container (for example, chemical name) and the dangers present must both be listed on this label. This warning about hazards can be distributed in a variety of ways. Employers want to choose a solution that will function in each place.

The following label indicates that the chemical does not pose a health risk.

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Noble gases exist as monatomic gases, which means that their molecules consist of a single atom.

A "Noble gas" can be defined as a gas which does not undergo chemical reactions. Examples of Noble gases are helium, Neon, Argon, Krypton, Xenon, and Radon.

Properties of noble gases:

Noble gases are the least reactive of all elements because they have eight valence electrons, which fill their outer energy level. That's why noble gases rarely react with other elements and form compounds.

Atoms of noble gases do not bond with other gases. Only helium exists as atoms of Helium, not as diatomic molecules. Helium does not form compounds with atoms of other elements.

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The correct formula of the molecule is C4H9O2.

The model of a compound is a representation of the molecule. It gives us an idea of what the molecule looks like as well as its molecular formula.

Looking at the structure of the compound as shown in the model in the question, the correct formula of the molecule is C4H9O2.

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Answer:C4H9O2.

Explanation:

Answer:

Electric current

Definition:

The time rate of flow of electric charge, in the direction that a positive moving charge would take and having magnitude equal to the quantity of charge per unit time: measured in amperes.

Everything begins inside in the battery. The battery's zinc metal undergoes oxidation; here is where the flow of electrons into the conductors begins. Electrical field attraction will lead the wire's existing electrons to move towards the battery's positive terminal, and the loose electrons caused by the zinc metal will begin to fill the wire's empty spaces. process continues until the zinc metal's oxidation ceases. At rechargeable batteries, the oxidation-reduction process is also reversed by charging the battery, allowing the stored electrons in the positive terminal to flow back to the zinc metal's negative terminal.

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The best way to make an accurate measurement of the height of a polar liquid is to take the reading from the lowest point of the meniscus.

The meniscus of a liquid is a curved that occurs at the top of a liquid placed in a container as a result of the attractive forces between the molecules of a the liquid.

Polar substances such as water have a concave meniscus as they dip downwards.

Therefore, the best way to make an accurate measurement of the height of a polar liquid is to take the reading from the lowest point of the meniscus.

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80% copper (Cu)

Cu: 80 :  63.546 = 1.259

O: 20 : 16 = 1.25

Cu:O = 1 : 1

the formula: CuO

89% copper (Cu)

Cu: 89 :  63.546 = 1.4

O: 11 : 16 = 0.6875

Cu:O = 2:1

the formula: Cu₂O

Answer:

Dalton law states that the partial pressure of a gas in a mixture of gases is equal to the total pressure of the mixture.

The steps usually involves adding the known solution (the titrant) to a known quantity of the unknown solution (the analyte) until the reaction is complete which can be understood in detail as below with the help of through out process of titration.

A titration is a technique used to work out the concentration of an unknown solution based on its chemical reaction with a solution of known concentration.

Steps in order to determine the concenteration of base solution ;  

(Acid-Base Titration)

                                          ​N₁V₁=N₂V₂

          ​Mass = Equivalent weight  x  Normality \  Volume  {1000}

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