An atom is said to be in an excited state when it possesses more energy than when it is in its
ground state.
True or false?

Answer:

Metals

1) Sodium : It is used in the formation of table salt i. e. sodium chloride.

2) Copper : It is used in the wires of electricity due to better conduction.

3) Silver : It is used in wires and for making jewelry.

4) Aurum: It is used for making jewelry.

Non metals

1) Chlorine : It is used in the production of sodium chloride salt which is used in foods.

2) Flourine : It is used in making toothpaste.

3) Hydrogen : It is used in the formation of acids.

4) Oxygen : It is widely used in the production of steel and plastic.

Answer:

[tex]39 ^\circ C[/tex]

Explanation:

Given,

V₁ = 18.5 L

T₁ = 18.5° C = 273 + 18.5 = 291.5 K

V₂ = 19.8 L

T₂ = ?

Pressure is constant

Using ideal gas equation

[tex]\dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}[/tex]

[tex]\dfrac{18.5}{291.5}=\dfrac{19.8}{T_2}[/tex]

[tex]T_2 = 312 K[/tex]

[tex]T_2 = 312 -273 =39 ^\circ C[/tex]

The temperature when the chamber has a volume of 19.8 L should be considered as the 39 degrees.

Since

V₁ = 18.5 L

T₁ = 18.5° C = 273 + 18.5 = 291.5 K

V₂ = 19.8 L

So here the final temperature should be

V1/T1 = V2/T2

18.5 L/291.5 = 19.8 / T2

So T2 = 312 k

= 312 - 273

= 39 degrees

hence, The temperature when the chamber has a volume of 19.8 L should be considered as the 39 degrees.

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Answer:

Metal, non-metal , and metaliod

Explanation:

Answer:

metal, nonmetal and metalloid

Explanation:

Answer:

the answer the gravity

Explanation:

Answer:

The pressure in the container is 1,7 atm.

Explanation:

We convert the unit of temperature in Celsius into Kelvin:

0°C= 273K --> 45°C= 45 + 273= 318 K

We use the formula:

PV=nRT ---> P =nRT/V

P= 1,20 mol x 0,082 l atm/K mol x 318 K/18,0 L

P= 1, 7384 atm

Final answer:

The hydrologic or water cycle is the term for the movement of water between the ground, atmosphere, and bodies of water. It occurs through processes like evaporation, transpiration, condensation, precipitation, surface runoff, and groundwater flow, primarily driven by solar energy and gravity.

Explanation:

The movement of water between the ground, the atmosphere, and bodies of water is called the hydrologic cycle or water cycle. This cycle describes the continuous movement of water as it is evaporated from surfaces like rivers, lakes, and oceans into the atmosphere, forms clouds, precipitates as rain or snow, and returns to the surface. The cycle is driven by solar energy and gravity, moving water through various states: liquid, solid (ice), and vapor.

Water reaches the atmosphere through evaporation, transpiration (from plants), and sublimation (ice to water vapor). It returns as precipitation and may flow over the land as surface runoff or infiltrate into the ground to become groundwater, which slowly moves and can discharge into other bodies of water or return to the ocean.

Answer:

1.06M

Explanation:

Given parameters:

Mass of HBr  = 50g

Volume of water  = 600mL

unknown:

Molarity of the solution = ?

Solution:

The molarity of a substance is the number of moles of solute in a volume of solution.

   Mathematically;

             Molarity  = [tex]\frac{number of moles }{volume}[/tex]

Since the number of moles is unknown, let us solve for it;

         Number of moles  = [tex]\frac{mass}{molar mass}[/tex]

               Molar mass of HBr  = 1 + 80  = 81g/mol

    Number of moles  = [tex]\frac{50}{81}[/tex]    = 0.64mole

Convert the volume to liters or dm³;  600mL  =  0.6L or 0.6 dm³

Input the parameters and solve;

            Molarity  = [tex]\frac{0.64}{0.6}[/tex]   = 1.06M

Answer:

A

Explanation

The product side is on the right, FeO + H2. H represents hydrogen, the number after it is the sbscript, which indicates that there are two hydrogen atoms.

There are two atoms of hydrogen  in the product side of the balanced chemical equation.

Chemical equation is a symbolic representation of a chemical reaction which is written in the form of symbols and chemical formulas.The reactants are present on the left hand side while the products are present on the right hand side.

A plus sign is present between reactants and products if they are more than one in any case and an arrow is present pointing towards the product side which indicates the direction of the reaction .There are coefficients present next to the chemical symbols and formulas .

The first chemical equation was put forth by Jean Beguin in 1615.By making use of chemical equations the direction of reaction ,state of reactants and products can be stated. In the chemical equations even the temperature to be maintained and catalyst can be mentioned.

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Answer:

Explanation:

Molar mass of C4H10 = 12x 4 + 1 x 10= 48+ 10=58g.

Also note that molar mass of a substance is equivalent to Avogadro's number (6.02 X 10^-23)

Hence,

6.02 X 10^-23 molecules of ethane was burned in 58g of ethane

So, 4.10 X 10^24 molecules of ethane will burn in xg of ethane.

Cross multiply:

6.02 X 10^-23x = 58 X 4.10 X 10^24

6.02 X 10^-23x = 2.378 X 10 ^26

Dividing both sides by the coefficient of 'x'

x = 2.378 X 10^26/(6.02X 10^-23)

x = 3.95 X10^48g approximately

x = 4.0 X 10^48g

Or

Mole = number of elementary

particless / Avogadro's number

Where,

No of elementary particles= 4.10 X 10^24 molecules

Avogadro's number= 6.02 x 10^-23

Therefore,

Mole = 4.10 X 10^24/ (6.02 X 10^-23)

= 6.81 X 10^ 46 moles.

But mole = mass / molar mass

Mass = mole x molar mass

where

Molar mass of C4H10 = 12x 4 + 1 x 10= 48+ 10=58g/mol

Mass= 6.81 X 10^46 X 58

= 3.95 X 10^48g approximately

= 4.0 X 10^ 48g.

Thanks

Answer: specie

Explanation:

A specie is the smallest group of organisms with similar characteristics and are capable of living with each other and breeding together freely. They give rise to young ones (offspring) that resembles the parents and can also breed with organisms of same species.

Examples of species include

- a group of lizards

- a group of human beings etc

A species is defined as a group of organisms that can mate

A species is a fundamental unit of biological classification. It comprises individuals that can interbreed and produce fertile offspring, sharing common characteristics. Species diversity is vital to biodiversity and plays a central role in ecology and evolutionary biology studies.

Thus, a species is a group of individual organisms that interbreed and produce fertile, viable offspring. According to this definition, one species is distinguished from another when, in nature, it is not possible for matings between individuals from each species to produce fertile offspring. This reproductive isolation is an important factor in defining species.

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Answer:number of protons in the nucleus and number of electrons in the different shell                                                                                                    

explained : determine the position in the periodic table. ... Their position is decided by their Atomic Number which is the number of protons in the nucleus of the atom.

Answer:

[tex]2.5\cdot 10^6 Hz[/tex]

Explanation:

The relationship between the speed of a wave, its frequency and its wavelength is given by the wave equation:

[tex]v=f\lambda[/tex]

where

v is the wave speed

f is the frequency of the wave, which is the number of cycles completed by the wave in one oscillation

[tex]\lambda[/tex] is the wavelength, which is the distance between two consecutive crests of the wave

For the wave in this problem we have:

v = 5000 m/s is the speed

[tex]\lambda=0.002 m[/tex] is the wavelength of the wave

Solving for f, we find the frequency:

[tex]f=\frac{v}{\lambda}=\frac{5000}{0.002}=2.5\cdot 10^6 Hz[/tex]

Answer: Acetylene : -1,256 kJ/mol

Ethanol : -1,277 kJ/mol

Explanation:

The enthalpy of combustion of acetylene is -1299 kJ/mol and the enthalpy of combustion of ethanol is -1367 kJ/mol.

To calculate the enthalpy of combustion of each substance, we need to use the equation:

ΔHcombustion = ΣΔHf(products) - ΣΔHf(reactants)

Where ΔHcombustion is the enthalpy of combustion, ΣΔHf(products) is the sum of the enthalpies of formation of the products, and ΣΔHf(reactants) is the sum of the enthalpies of formation of the reactants.

Using the enthalpies of formation (AH) given in the table, we can calculate the enthalpy of combustion of each substance:

Acetylene:

C₂H₂ + (5/2)O₂ → 2CO₂ + H₂O

ΔHcombustion = [2(-393.5) + (-241.8)] - [228.8] = -1299 kJ/mol

Ethanol:

C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O

ΔHcombustion = [2(-393.5) + 3(-241.8)] - [-235.1] = -1367 kJ/mol

Therefore, the enthalpy of combustion of acetylene is -1299 kJ/mol and the enthalpy of combustion of ethanol is -1367 kJ/mol.

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Answer:

0.016M

Explanation:

First we find the mole of AgNO3 by using the formula mass/molar mass..

Then we find molarity by the formula mole/volume...

I hope you get this..

Answer:

a

Explanation:

a is the 100% correct answer

Answer:

C

Explanation:

You can see in the chemical equation that 7 [tex]O_{2}[/tex] are used up to produce 6[tex]H_{2}O[/tex]

Answer:

There should be the refraction for light to change a material.

Answer: change in speed

Explanation: the change in speed causes light Ray's to change direction. This directional change is called refraction.

Answer:

V₁  = 10 mL

Explanation:

Given data:

Initial volume of HCl = ?

Initial molarity = 3.0 M

Final molarity = 0.10 M

Final volume = 300.0 mL

Solution:

Formula:

M₁V₁  =  M₂V₂

M₁ = Initial molarity

V₁  =  Initial volume of HCl

M₂ =Final molarity

V₂ = Final volume

Now we will put the values.

3.0 M ×V₁  =  0.10 M×300.0 mL

3.0 M ×V₁  = 30 M.mL

V₁  = 30 M.mL /3.0 M

V₁  = 10 mL

Answer:

There are 2, 01 moles of helium in the container

Explanation:

We use the formula PV=nRT. We convert of pressure the unit kPa into atm:

101,325 kPa---1 atm

245   kPa   ----x= (245  kPa x 1 atm)/101,325 kPa=2,42 atm

PV= nRT  --->  n=PV/RT

n= 2, 42 atm x 21, 5 L/ 0,082 l atm /K mol  x315K

n=2, 012620871 mol

Answer:

b

Explanation:

Answer:

0.06 kg

Explanation:

Given data:

Mass of frisbee = ?

Velocity of frisbee  = 11 m/s

Energy of frisbee = 3.6 j

Solution:

K.E = 1/2 mv²

Now we will put  the values in this formula.

3.6 J = 1/2 m(11m/s)²

3.6 j = 0.5 ×121m²/s² × m

3.6 j = 60.5 m²/s² × m

m = 3.6 j/60.5 m²/s²

m= 0.06 j.m⁻².s²

j = Kg.m².s⁻²

m= 0.06 Kg.m².s⁻² .m⁻².s²

m = 0.06 kg

Answer:

there are billions, and more that we haven't yet explored, it is just let the sea only a lot more floaty!

hope this helps

Answer:

A disproportionation redox reaction  

Explanation:

1. Assign an oxidation number to every atom in the equation

[tex]2\stackrel{\hbox{$\mathbf{+4}$}}{\hbox{N}}\stackrel{\hbox{-2}}{\hbox{O }}_{2} + 2\stackrel{\hbox{-2}}{\hbox{O}}\stackrel{\hbox{+1}}{\hbox{H}^{-}} \longrightarrow \, (\stackrel{\hbox{$\mathbf{+3}$}}{\hbox{N}}\stackrel{\hbox{-2}}{\hbox{O }}_{2})^{-} + (\stackrel{\hbox{$\mathbf{+5}$}}{\hbox{N}}\stackrel{\hbox{-2}}{\hbox{O}_{3}})^{-} +\stackrel{\hbox{+1}}{\hbox{H}}_{2}\stackrel{\hbox{-2}}{\hbox{O}}[/tex]

2. Identify the atoms that change their oxidation number

N in NO₂: +4 ⟶ +3 in NO₂⁻

N in NO₂: +4 ⟶ +5 in NO₃⁻

3. Identify the type of change

This is a disproportionation — a reaction in which one substance is simultaneously oxidized and reduced.

Answer:

D

Explanation:

Final answer:

Balancing the provided chemical equation for the combustion of ethane results in a balanced equation with integer-only coefficients: 2 C2H6 + 7 O2 → 4 CO2 + 6 H2O, showcasing the adherence to the law of conservation of mass.

Explanation:

The question involves balancing a chemical equation which is a fundamental skill in chemistry. The correct and balanced equation for the combustion of ethane (C2H6) in oxygen is as follows:

2 C2H6 + 7 O2 → 4 CO2 + 6 H2O

This equation demonstrates that when ethane (C2H6) combusts with oxygen (O2), it produces carbon dioxide (CO2) and water (H2O). Balancing a chemical equation ensures that there are an equal number of atoms for each element on both sides of the equation, adhering to the law of conservation of mass. This equation is balanced by ensuring there are equal numbers of carbon, hydrogen, and oxygen atoms on both reactant and product sides. After initial attempts that might lead to fractional coefficients, multiplying all coefficients by an appropriate factor to achieve integer-only coefficients is a commonly used strategy as illustrated by the multiplication of each coefficient by 2 in this case.

Answer:

It's C.

Explanation:

Firstly, the burning of carbon produces C02, a greenhouse gas. As nuclear fission does not produce carbon dioxide, it is not A. The decay of radioactive isotopes is not fission, or spliting into 2 parts.

As fission means to split, it is C.

Answer:

20.179

Explanation:

The answer is 20.179 because the element you are talking about is the element  Neon, which has the atomic mass of 20.179.

An example of an exothermic reaction is : C. oxidation of iron. The Exothermic process involves the liberation of heat.

An exothermic reaction is a chemical or physical reaction that gives heat. It takes out energy to its surroundings. The energy needed for the reaction to occur is less than the total energy released.

In the oxidation of iron, the heat is released while all the other processes are endothermic in which is heat is absorbed.

Thus, the correct option is C.

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Answer:

The concentrations of the products and reactants do not change.

Explanation:

The following information is missing:

If the reaction is at dynamic equilibrium at 500 K, which statement applies to the given chemical system?

Dynamic equilibrium means that the rate of the forward and reverse reactions are equal and different from zero. Then, the concentrations of the products and reactants do not change.

Answer:

c

Explanation:

Answer:

Mass = 14.64 g

Explanation:

Given data:

Volume of solution = 1.25 L

Molarity of Solution = 0.15 M

Mass of CaF₂ = ?

Solution:

Molarity is used to describe the concentration of solution. It tells how many moles are dissolve in per litter of solution.

Formula:

Molarity = number of moles of solute / L of solution

We will calculate the number of moles of CaF₂ and then determine the mass by using number of moles.

0.15 M =  number of moles of solute / 1.25 L

number of moles of solute = 0.15 M ×  1.25 L

number of moles of solute = 0.1875 mol/L × L

number of moles of solute = 0.1875 mol

Mass in gram:

Mass = number of moles × molar mass

Mass = 0.1875 mol ×78.07 g/mol

Mass = 14.64 g

The Mass of CaF₂ is 14.64 g. Molarity is the ratio of number of moles over the volume of solution.

Given:

Volume of solution = 1.25 L

Molarity of Solution = 0.15 M

To find:

Mass of CaF₂ = ?

Molarity is used to describe the concentration of solution. It is given by number of moles divided by volume of solution in litres.

Molarity = number of moles of solute / L of solution

We will calculate the number of moles of CaF₂ and then determine the mass by using number of moles.

0.15 M =  Number of moles of solute / 1.25 L

Number of moles of solute = 0.15 M *  1.25 L

Number of moles of solute = 0.1875 mol/L * L

Number of moles of solute = 0.1875 mol

Calculation of mass:

Mass = number of moles / molar mass

Mass = 0.1875 mol *78.07 g/mol

Mass = 14.64 g

Thus, the mass of CaF₂ is 14.64 grams.

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